修改完成填充日期格式的问题

src/main/java/com/alibaba/excel/analysis/v03/handlers/NumberRecordHandler.java

@@ -21,7 +21,7 @@ public class NumberRecordHandler extends AbstractXlsRecordHandler implements Ign
     @Override
     public void processRecord(XlsReadContext xlsReadContext, Record record) {
         NumberRecord nr = (NumberRecord)record;
-        CellData cellData = CellData.newInstance(BigDecimal.valueOf(nr.getValue()), nr.getRow(), (int)nr.getColumn());
+        CellData<?>cellData = CellData.newInstance(BigDecimal.valueOf(nr.getValue()), nr.getRow(), (int)nr.getColumn());
         short dataFormat = (short)xlsReadContext.xlsReadWorkbookHolder().getFormatTrackingHSSFListener().getFormatIndex(
             nr);
         cellData.setDataFormat(dataFormat);

src/main/java/com/alibaba/excel/analysis/v03/handlers/StringRecordHandler.java

@@ -23,7 +23,7 @@ public class StringRecordHandler extends AbstractXlsRecordHandler implements Ign
         // String for formula
         StringRecord srec = (StringRecord)record;
         XlsReadSheetHolder xlsReadSheetHolder = xlsReadContext.xlsReadSheetHolder();
-        CellData tempCellData = xlsReadSheetHolder.getTempCellData();
+        CellData<?>tempCellData = xlsReadSheetHolder.getTempCellData();
         if (tempCellData == null) {
             LOGGER.warn("String type formula but no value found.");
             return;

src/main/java/com/alibaba/excel/analysis/v07/handlers/CellInlineStringValueTagHandler.java

@@ -15,7 +15,7 @@ public class CellInlineStringValueTagHandler extends AbstractCellValueTagHandler
     @Override
     protected void setStringValue(XlsxReadContext xlsxReadContext) {
         // This is a special form of string
-        CellData tempCellData = xlsxReadContext.xlsxReadSheetHolder().getTempCellData();
+        CellData<?> tempCellData = xlsxReadContext.xlsxReadSheetHolder().getTempCellData();
         XSSFRichTextString richTextString = new XSSFRichTextString(tempCellData.getStringValue());
         tempCellData.setStringValue(richTextString.toString());
     }

src/main/java/com/alibaba/excel/constant/BuiltinFormats.java

@@ -17,6 +17,8 @@ import java.util.Locale;
  **/
 public class BuiltinFormats {
 
+    public static short GENERAL = 0;
+
     public static final String[] BUILTIN_FORMATS_CN = {
         // 0
         "General",

src/main/java/com/alibaba/excel/converters/AutoConverter.java

@@ -10,10 +10,10 @@ import com.alibaba.excel.metadata.property.ExcelContentProperty;
  *
  * @author Jiaju Zhuang
  */
-public class AutoConverter implements Converter {
+public class AutoConverter implements Converter<Object> {
 
     @Override
-    public Class supportJavaTypeKey() {
+    public Class<?> supportJavaTypeKey() {
         return null;
     }
 
@@ -23,13 +23,13 @@ public class AutoConverter implements Converter {
     }
 
     @Override
-    public Object convertToJavaData(CellData cellData, ExcelContentProperty contentProperty,
+    public Object convertToJavaData(CellData<?> cellData, ExcelContentProperty contentProperty,
         GlobalConfiguration globalConfiguration) {
         return null;
     }
 
     @Override
-    public CellData convertToExcelData(Object value, ExcelContentProperty contentProperty,
+    public CellData<?> convertToExcelData(Object value, ExcelContentProperty contentProperty,
         GlobalConfiguration globalConfiguration) {
         return null;
     }

src/main/java/com/alibaba/excel/converters/Converter.java

@@ -22,7 +22,7 @@ public interface Converter<T> {
      *
      * @return Support for Java class
      */
-    default Class<T> supportJavaTypeKey() {
+    default Class<?> supportJavaTypeKey() {
         throw new UnsupportedOperationException("The current operation is not supported by the current converter.");
     }
 

src/main/java/com/alibaba/excel/converters/ConverterKeyBuild.java

@@ -1,9 +1,9 @@
 package com.alibaba.excel.converters;
 
-import java.util.HashMap;
 import java.util.Map;
 
 import com.alibaba.excel.enums.CellDataTypeEnum;
+import com.alibaba.excel.util.MapUtils;
 
 /**
  * Converter unique key.Consider that you can just use class as the key.
@@ -12,7 +12,7 @@ import com.alibaba.excel.enums.CellDataTypeEnum;
  */
 public class ConverterKeyBuild {
 
-    private static final Map<String, String> BOXING_MAP = new HashMap<String, String>(16);
+    private static final Map<String, String> BOXING_MAP = MapUtils.newHashMap();
 
     static {
         BOXING_MAP.put(int.class.getName(), Integer.class.getName());
@@ -25,7 +25,7 @@ public class ConverterKeyBuild {
         BOXING_MAP.put(boolean.class.getName(), Boolean.class.getName());
     }
 
-    public static String buildKey(Class clazz) {
+    public static String buildKey(Class<?> clazz) {
         String className = clazz.getName();
         String boxingClassName = BOXING_MAP.get(clazz.getName());
         if (boxingClassName == null) {
@@ -34,7 +34,11 @@ public class ConverterKeyBuild {
         return boxingClassName;
     }
 
-    public static String buildKey(Class clazz, CellDataTypeEnum cellDataTypeEnum) {
+    public static String buildKey(Class<?> clazz, CellDataTypeEnum cellDataTypeEnum) {
-        return buildKey(clazz) + "-" + cellDataTypeEnum.toString();
+        String key = buildKey(clazz);
+        if (cellDataTypeEnum == null) {
+            return key;
+        }
+        return key + "-" + cellDataTypeEnum.toString();
     }
 }

src/main/java/com/alibaba/excel/converters/DefaultConverterLoader.java

@@ -98,7 +98,7 @@ public class DefaultConverterLoader {
     }
 
     private static void initDefaultWriteConverter() {
-        defaultWriteConverter = MapUtils.newHashMapWithExpectedSize(20);
+        defaultWriteConverter = MapUtils.newHashMapWithExpectedSize(40);
         putWriteConverter(new BigDecimalNumberConverter());
         putWriteConverter(new BooleanBooleanConverter());
         putWriteConverter(new ByteNumberConverter());
@@ -114,6 +114,18 @@ public class DefaultConverterLoader {
         putWriteConverter(new ByteArrayImageConverter());
         putWriteConverter(new BoxingByteArrayImageConverter());
         putWriteConverter(new UrlImageConverter());
+
+        // In some cases, it must be converted to string
+        putWriteStringConverter(new BigDecimalStringConverter());
+        putWriteStringConverter(new BooleanStringConverter());
+        putWriteStringConverter(new ByteStringConverter());
+        putWriteStringConverter(new DateStringConverter());
+        putWriteStringConverter(new DoubleStringConverter());
+        putWriteStringConverter(new FloatStringConverter());
+        putWriteStringConverter(new IntegerStringConverter());
+        putWriteStringConverter(new LongStringConverter());
+        putWriteStringConverter(new ShortStringConverter());
+        putWriteStringConverter(new StringStringConverter());
     }
 
     /**
@@ -129,6 +141,11 @@ public class DefaultConverterLoader {
         defaultWriteConverter.put(ConverterKeyBuild.buildKey(converter.supportJavaTypeKey()), converter);
     }
 
+    private static void putWriteStringConverter(Converter<?> converter) {
+        defaultWriteConverter.put(
+            ConverterKeyBuild.buildKey(converter.supportJavaTypeKey(), converter.supportExcelTypeKey()), converter);
+    }
+
     /**
      * Load default read converter
      *

src/main/java/com/alibaba/excel/converters/bigdecimal/BigDecimalBooleanConverter.java

@@ -16,7 +16,7 @@ import com.alibaba.excel.metadata.property.ExcelContentProperty;
 public class BigDecimalBooleanConverter implements Converter<BigDecimal> {
 
     @Override
-    public Class supportJavaTypeKey() {
+    public Class<BigDecimal> supportJavaTypeKey() {
         return BigDecimal.class;
     }
 
@@ -26,7 +26,7 @@ public class BigDecimalBooleanConverter implements Converter<BigDecimal> {
     }
 
     @Override
-    public BigDecimal convertToJavaData(CellData cellData, ExcelContentProperty contentProperty,
+    public BigDecimal convertToJavaData(CellData<?> cellData, ExcelContentProperty contentProperty,
         GlobalConfiguration globalConfiguration) {
         if (cellData.getBooleanValue()) {
             return BigDecimal.ONE;
@@ -35,12 +35,12 @@ public class BigDecimalBooleanConverter implements Converter<BigDecimal> {
     }
 
     @Override
-    public CellData convertToExcelData(BigDecimal value, ExcelContentProperty contentProperty,
+    public CellData<?> convertToExcelData(BigDecimal value, ExcelContentProperty contentProperty,
         GlobalConfiguration globalConfiguration) {
         if (BigDecimal.ONE.equals(value)) {
-            return new CellData(Boolean.TRUE);
+            return new CellData<>(Boolean.TRUE);
         }
-        return new CellData(Boolean.FALSE);
+        return new CellData<>(Boolean.FALSE);
     }
 
 }

src/main/java/com/alibaba/excel/converters/bigdecimal/BigDecimalNumberConverter.java

@@ -18,7 +18,7 @@ import com.alibaba.excel.write.metadata.holder.WriteHolder;
 public class BigDecimalNumberConverter implements Converter<BigDecimal> {
 
     @Override
-    public Class supportJavaTypeKey() {
+    public Class<BigDecimal> supportJavaTypeKey() {
         return BigDecimal.class;
     }
 
@@ -28,7 +28,7 @@ public class BigDecimalNumberConverter implements Converter<BigDecimal> {
     }
 
     @Override
-    public BigDecimal convertToJavaData(CellData cellData, ExcelContentProperty contentProperty,
+    public BigDecimal convertToJavaData(CellData<?> cellData, ExcelContentProperty contentProperty,
         GlobalConfiguration globalConfiguration) {
         return cellData.getNumberValue();
     }

src/main/java/com/alibaba/excel/converters/bigdecimal/BigDecimalStringConverter.java

@@ -18,7 +18,7 @@ import com.alibaba.excel.util.NumberUtils;
 public class BigDecimalStringConverter implements Converter<BigDecimal> {
 
     @Override
-    public Class supportJavaTypeKey() {
+    public Class<BigDecimal> supportJavaTypeKey() {
         return BigDecimal.class;
     }
 
@@ -28,13 +28,13 @@ public class BigDecimalStringConverter implements Converter<BigDecimal> {
     }
 
     @Override
-    public BigDecimal convertToJavaData(CellData cellData, ExcelContentProperty contentProperty,
+    public BigDecimal convertToJavaData(CellData<?> cellData, ExcelContentProperty contentProperty,
         GlobalConfiguration globalConfiguration) throws ParseException {
         return NumberUtils.parseBigDecimal(cellData.getStringValue(), contentProperty);
     }
 
     @Override
-    public CellData convertToExcelData(BigDecimal value, ExcelContentProperty contentProperty,
+    public CellData<?> convertToExcelData(BigDecimal value, ExcelContentProperty contentProperty,
         GlobalConfiguration globalConfiguration) {
         return NumberUtils.formatToCellDataString(value, contentProperty);
     }

src/main/java/com/alibaba/excel/converters/booleanconverter/BooleanBooleanConverter.java

@@ -14,7 +14,7 @@ import com.alibaba.excel.metadata.property.ExcelContentProperty;
 public class BooleanBooleanConverter implements Converter<Boolean> {
 
     @Override
-    public Class supportJavaTypeKey() {
+    public Class<?> supportJavaTypeKey() {
         return Boolean.class;
     }
 
@@ -24,15 +24,15 @@ public class BooleanBooleanConverter implements Converter<Boolean> {
     }
 
     @Override
-    public Boolean convertToJavaData(CellData cellData, ExcelContentProperty contentProperty,
+    public Boolean convertToJavaData(CellData<?> cellData, ExcelContentProperty contentProperty,
         GlobalConfiguration globalConfiguration) {
         return cellData.getBooleanValue();
     }
 
     @Override
-    public CellData convertToExcelData(Boolean value, ExcelContentProperty contentProperty,
+    public CellData<?> convertToExcelData(Boolean value, ExcelContentProperty contentProperty,
         GlobalConfiguration globalConfiguration) {
-        return new CellData(value);
+        return new CellData<>(value);
     }
 
 }

src/main/java/com/alibaba/excel/converters/booleanconverter/BooleanNumberConverter.java

@@ -15,7 +15,7 @@ import com.alibaba.excel.metadata.property.ExcelContentProperty;
  */
 public class BooleanNumberConverter implements Converter<Boolean> {
     @Override
-    public Class supportJavaTypeKey() {
+    public Class<?> supportJavaTypeKey() {
         return Boolean.class;
     }
 
@@ -25,7 +25,7 @@ public class BooleanNumberConverter implements Converter<Boolean> {
     }
 
     @Override
-    public Boolean convertToJavaData(CellData cellData, ExcelContentProperty contentProperty,
+    public Boolean convertToJavaData(CellData<?> cellData, ExcelContentProperty contentProperty,
         GlobalConfiguration globalConfiguration) {
         if (BigDecimal.ONE.compareTo(cellData.getNumberValue()) == 0) {
             return Boolean.TRUE;
@@ -34,12 +34,12 @@ public class BooleanNumberConverter implements Converter<Boolean> {
     }
 
     @Override
-    public CellData convertToExcelData(Boolean value, ExcelContentProperty contentProperty,
+    public CellData<?> convertToExcelData(Boolean value, ExcelContentProperty contentProperty,
         GlobalConfiguration globalConfiguration) {
         if (value) {
-            return new CellData(BigDecimal.ONE);
+            return new CellData<>(BigDecimal.ONE);
         }
-        return new CellData(BigDecimal.ZERO);
+        return new CellData<>(BigDecimal.ZERO);
     }
 
 }

src/main/java/com/alibaba/excel/converters/booleanconverter/BooleanStringConverter.java

@@ -14,7 +14,7 @@ import com.alibaba.excel.metadata.property.ExcelContentProperty;
 public class BooleanStringConverter implements Converter<Boolean> {
 
     @Override
-    public Class supportJavaTypeKey() {
+    public Class<?> supportJavaTypeKey() {
         return Boolean.class;
     }
 
@@ -24,15 +24,15 @@ public class BooleanStringConverter implements Converter<Boolean> {
     }
 
     @Override
-    public Boolean convertToJavaData(CellData cellData, ExcelContentProperty contentProperty,
+    public Boolean convertToJavaData(CellData<?> cellData, ExcelContentProperty contentProperty,
         GlobalConfiguration globalConfiguration) {
         return Boolean.valueOf(cellData.getStringValue());
     }
 
     @Override
-    public CellData convertToExcelData(Boolean value, ExcelContentProperty contentProperty,
+    public CellData<?> convertToExcelData(Boolean value, ExcelContentProperty contentProperty,
         GlobalConfiguration globalConfiguration) {
-        return new CellData(value.toString());
+        return new CellData<>(value.toString());
     }
 
 }

src/main/java/com/alibaba/excel/converters/bytearray/BoxingByteArrayImageConverter.java

@@ -13,7 +13,7 @@ import com.alibaba.excel.metadata.property.ExcelContentProperty;
  */
 public class BoxingByteArrayImageConverter implements Converter<Byte[]> {
     @Override
-    public Class supportJavaTypeKey() {
+    public Class<?> supportJavaTypeKey() {
         return Byte[].class;
     }
 
@@ -23,19 +23,19 @@ public class BoxingByteArrayImageConverter implements Converter<Byte[]> {
     }
 
     @Override
-    public Byte[] convertToJavaData(CellData cellData, ExcelContentProperty contentProperty,
+    public Byte[] convertToJavaData(CellData<?> cellData, ExcelContentProperty contentProperty,
         GlobalConfiguration globalConfiguration) {
         throw new UnsupportedOperationException("Cannot convert images to byte arrays");
     }
 
     @Override
-    public CellData convertToExcelData(Byte[] value, ExcelContentProperty contentProperty,
+    public CellData<?> convertToExcelData(Byte[] value, ExcelContentProperty contentProperty,
         GlobalConfiguration globalConfiguration) {
         byte[] byteValue = new byte[value.length];
         for (int i = 0; i < value.length; i++) {
             byteValue[i] = value[i];
         }
-        return new CellData(byteValue);
+        return new CellData<>(byteValue);
     }
 
 }

src/main/java/com/alibaba/excel/converters/bytearray/ByteArrayImageConverter.java

@@ -13,7 +13,7 @@ import com.alibaba.excel.metadata.property.ExcelContentProperty;
  */
 public class ByteArrayImageConverter implements Converter<byte[]> {
     @Override
-    public Class supportJavaTypeKey() {
+    public Class<byte[]> supportJavaTypeKey() {
         return byte[].class;
     }
 
@@ -23,15 +23,15 @@ public class ByteArrayImageConverter implements Converter<byte[]> {
     }
 
     @Override
-    public byte[] convertToJavaData(CellData cellData, ExcelContentProperty contentProperty,
+    public byte[] convertToJavaData(CellData<?> cellData, ExcelContentProperty contentProperty,
         GlobalConfiguration globalConfiguration) {
         throw new UnsupportedOperationException("Cannot convert images to byte arrays");
     }
 
     @Override
-    public CellData convertToExcelData(byte[] value, ExcelContentProperty contentProperty,
+    public CellData<?> convertToExcelData(byte[] value, ExcelContentProperty contentProperty,
         GlobalConfiguration globalConfiguration) {
-        return new CellData(value);
+        return new CellData<>(value);
     }
 
 }

src/main/java/com/alibaba/excel/converters/byteconverter/ByteBooleanConverter.java

@@ -16,7 +16,7 @@ public class ByteBooleanConverter implements Converter<Byte> {
     private static final Byte ZERO = (byte)0;
 
     @Override
-    public Class supportJavaTypeKey() {
+    public Class<?> supportJavaTypeKey() {
         return Byte.class;
     }
 
@@ -26,7 +26,7 @@ public class ByteBooleanConverter implements Converter<Byte> {
     }
 
     @Override
-    public Byte convertToJavaData(CellData cellData, ExcelContentProperty contentProperty,
+    public Byte convertToJavaData(CellData<?> cellData, ExcelContentProperty contentProperty,
         GlobalConfiguration globalConfiguration) {
         if (cellData.getBooleanValue()) {
             return ONE;
@@ -35,12 +35,12 @@ public class ByteBooleanConverter implements Converter<Byte> {
     }
 
     @Override
-    public CellData convertToExcelData(Byte value, ExcelContentProperty contentProperty,
+    public CellData<?> convertToExcelData(Byte value, ExcelContentProperty contentProperty,
         GlobalConfiguration globalConfiguration) {
         if (ONE.equals(value)) {
-            return new CellData(Boolean.TRUE);
+            return new CellData<>(Boolean.TRUE);
         }
-        return new CellData(Boolean.FALSE);
+        return new CellData<>(Boolean.FALSE);
     }
 
 }

src/main/java/com/alibaba/excel/converters/byteconverter/ByteNumberConverter.java

@@ -18,7 +18,7 @@ import com.alibaba.excel.write.metadata.holder.WriteHolder;
 public class ByteNumberConverter implements Converter<Byte> {
 
     @Override
-    public Class supportJavaTypeKey() {
+    public Class<?> supportJavaTypeKey() {
         return Byte.class;
     }
 
@@ -28,7 +28,7 @@ public class ByteNumberConverter implements Converter<Byte> {
     }
 
     @Override
-    public Byte convertToJavaData(CellData cellData, ExcelContentProperty contentProperty,
+    public Byte convertToJavaData(CellData<?> cellData, ExcelContentProperty contentProperty,
         GlobalConfiguration globalConfiguration) {
         return cellData.getNumberValue().byteValue();
     }

src/main/java/com/alibaba/excel/converters/byteconverter/ByteStringConverter.java

@@ -17,7 +17,7 @@ import com.alibaba.excel.util.NumberUtils;
 public class ByteStringConverter implements Converter<Byte> {
 
     @Override
-    public Class supportJavaTypeKey() {
+    public Class<?> supportJavaTypeKey() {
         return Byte.class;
     }
 
@@ -27,13 +27,13 @@ public class ByteStringConverter implements Converter<Byte> {
     }
 
     @Override
-    public Byte convertToJavaData(CellData cellData, ExcelContentProperty contentProperty,
+    public Byte convertToJavaData(CellData<?> cellData, ExcelContentProperty contentProperty,
         GlobalConfiguration globalConfiguration) throws ParseException {
         return NumberUtils.parseByte(cellData.getStringValue(), contentProperty);
     }
 
     @Override
-    public CellData convertToExcelData(Byte value, ExcelContentProperty contentProperty,
+    public CellData<?> convertToExcelData(Byte value, ExcelContentProperty contentProperty,
         GlobalConfiguration globalConfiguration) {
         return NumberUtils.formatToCellDataString(value, contentProperty);
     }

src/main/java/com/alibaba/excel/converters/date/DateDateConverter.java

@@ -3,7 +3,9 @@ package com.alibaba.excel.converters.date;
 import java.util.Date;
 
 import com.alibaba.excel.converters.Converter;
+import com.alibaba.excel.enums.CellDataTypeEnum;
 import com.alibaba.excel.metadata.CellData;
+import com.alibaba.excel.metadata.GlobalConfiguration;
 import com.alibaba.excel.metadata.property.ExcelContentProperty;
 import com.alibaba.excel.util.WorkBookUtil;
 import com.alibaba.excel.write.metadata.holder.WriteHolder;
@@ -19,6 +21,17 @@ public class DateDateConverter implements Converter<Date> {
         return Date.class;
     }
 
+    @Override
+    public CellDataTypeEnum supportExcelTypeKey() {
+        return CellDataTypeEnum.DATE;
+    }
+
+    @Override
+    public Date convertToJavaData(CellData<?> cellData, ExcelContentProperty contentProperty,
+        GlobalConfiguration globalConfiguration) {
+        return cellData.getDateValue();
+    }
+
     @Override
     public CellData<?> convertToExcelData(Date value, ExcelContentProperty contentProperty,
         WriteHolder currentWriteHolder) throws Exception {

src/main/java/com/alibaba/excel/converters/date/DateNumberConverter.java

@@ -19,7 +19,7 @@ import com.alibaba.excel.metadata.property.ExcelContentProperty;
 public class DateNumberConverter implements Converter<Date> {
 
     @Override
-    public Class supportJavaTypeKey() {
+    public Class<?> supportJavaTypeKey() {
         return Date.class;
     }
 
@@ -29,7 +29,7 @@ public class DateNumberConverter implements Converter<Date> {
     }
 
     @Override
-    public Date convertToJavaData(CellData cellData, ExcelContentProperty contentProperty,
+    public Date convertToJavaData(CellData<?> cellData, ExcelContentProperty contentProperty,
         GlobalConfiguration globalConfiguration) {
         if (contentProperty == null || contentProperty.getDateTimeFormatProperty() == null) {
             return DateUtil.getJavaDate(cellData.getNumberValue().doubleValue(),
@@ -41,13 +41,13 @@ public class DateNumberConverter implements Converter<Date> {
     }
 
     @Override
-    public CellData convertToExcelData(Date value, ExcelContentProperty contentProperty,
+    public CellData<?> convertToExcelData(Date value, ExcelContentProperty contentProperty,
         GlobalConfiguration globalConfiguration) {
         if (contentProperty == null || contentProperty.getDateTimeFormatProperty() == null) {
-            return new CellData(
+            return new CellData<>(
                 BigDecimal.valueOf(DateUtil.getExcelDate(value, globalConfiguration.getUse1904windowing())));
         } else {
-            return new CellData(BigDecimal.valueOf(
+            return new CellData<>(BigDecimal.valueOf(
                 DateUtil.getExcelDate(value, contentProperty.getDateTimeFormatProperty().getUse1904windowing())));
         }
     }

src/main/java/com/alibaba/excel/converters/date/DateStringConverter.java

@@ -17,7 +17,7 @@ import com.alibaba.excel.util.DateUtils;
  */
 public class DateStringConverter implements Converter<Date> {
     @Override
-    public Class supportJavaTypeKey() {
+    public Class<?> supportJavaTypeKey() {
         return Date.class;
     }
 
@@ -27,7 +27,7 @@ public class DateStringConverter implements Converter<Date> {
     }
 
     @Override
-    public Date convertToJavaData(CellData cellData, ExcelContentProperty contentProperty,
+    public Date convertToJavaData(CellData<?> cellData, ExcelContentProperty contentProperty,
         GlobalConfiguration globalConfiguration) throws ParseException {
         if (contentProperty == null || contentProperty.getDateTimeFormatProperty() == null) {
             return DateUtils.parseDate(cellData.getStringValue(), null);
@@ -38,12 +38,12 @@ public class DateStringConverter implements Converter<Date> {
     }
 
     @Override
-    public CellData convertToExcelData(Date value, ExcelContentProperty contentProperty,
+    public CellData<?> convertToExcelData(Date value, ExcelContentProperty contentProperty,
         GlobalConfiguration globalConfiguration) {
         if (contentProperty == null || contentProperty.getDateTimeFormatProperty() == null) {
-            return new CellData(DateUtils.format(value, null));
+            return new CellData<>(DateUtils.format(value, null));
         } else {
-            return new CellData(DateUtils.format(value, contentProperty.getDateTimeFormatProperty().getFormat()));
+            return new CellData<>(DateUtils.format(value, contentProperty.getDateTimeFormatProperty().getFormat()));
         }
     }
 }

src/main/java/com/alibaba/excel/converters/doubleconverter/DoubleBooleanConverter.java

@@ -16,7 +16,7 @@ public class DoubleBooleanConverter implements Converter<Double> {
     private static final Double ZERO = 0.0;
 
     @Override
-    public Class supportJavaTypeKey() {
+    public Class<?> supportJavaTypeKey() {
         return Double.class;
     }
 
@@ -26,7 +26,7 @@ public class DoubleBooleanConverter implements Converter<Double> {
     }
 
     @Override
-    public Double convertToJavaData(CellData cellData, ExcelContentProperty contentProperty,
+    public Double convertToJavaData(CellData<?> cellData, ExcelContentProperty contentProperty,
         GlobalConfiguration globalConfiguration) {
         if (cellData.getBooleanValue()) {
             return ONE;
@@ -35,12 +35,12 @@ public class DoubleBooleanConverter implements Converter<Double> {
     }
 
     @Override
-    public CellData convertToExcelData(Double value, ExcelContentProperty contentProperty,
+    public CellData<?> convertToExcelData(Double value, ExcelContentProperty contentProperty,
         GlobalConfiguration globalConfiguration) {
         if (ONE.equals(value)) {
-            return new CellData(Boolean.TRUE);
+            return new CellData<>(Boolean.TRUE);
         }
-        return new CellData(Boolean.FALSE);
+        return new CellData<>(Boolean.FALSE);
     }
 
 }

src/main/java/com/alibaba/excel/converters/doubleconverter/DoubleNumberConverter.java

@@ -18,7 +18,7 @@ import com.alibaba.excel.write.metadata.holder.WriteHolder;
 public class DoubleNumberConverter implements Converter<Double> {
 
     @Override
-    public Class supportJavaTypeKey() {
+    public Class<?> supportJavaTypeKey() {
         return Double.class;
     }
 
@@ -28,7 +28,7 @@ public class DoubleNumberConverter implements Converter<Double> {
     }
 
     @Override
-    public Double convertToJavaData(CellData cellData, ExcelContentProperty contentProperty,
+    public Double convertToJavaData(CellData<?> cellData, ExcelContentProperty contentProperty,
         GlobalConfiguration globalConfiguration) {
         return cellData.getNumberValue().doubleValue();
     }

src/main/java/com/alibaba/excel/converters/doubleconverter/DoubleStringConverter.java

@@ -17,7 +17,7 @@ import com.alibaba.excel.util.NumberUtils;
 public class DoubleStringConverter implements Converter<Double> {
 
     @Override
-    public Class supportJavaTypeKey() {
+    public Class<?> supportJavaTypeKey() {
         return Double.class;
     }
 
@@ -27,13 +27,13 @@ public class DoubleStringConverter implements Converter<Double> {
     }
 
     @Override
-    public Double convertToJavaData(CellData cellData, ExcelContentProperty contentProperty,
+    public Double convertToJavaData(CellData<?> cellData, ExcelContentProperty contentProperty,
         GlobalConfiguration globalConfiguration) throws ParseException {
         return NumberUtils.parseDouble(cellData.getStringValue(), contentProperty);
     }
 
     @Override
-    public CellData convertToExcelData(Double value, ExcelContentProperty contentProperty,
+    public CellData<?> convertToExcelData(Double value, ExcelContentProperty contentProperty,
         GlobalConfiguration globalConfiguration) {
         return NumberUtils.formatToCellDataString(value, contentProperty);
     }

src/main/java/com/alibaba/excel/converters/file/FileImageConverter.java

@@ -17,7 +17,7 @@ import com.alibaba.excel.util.FileUtils;
  */
 public class FileImageConverter implements Converter<File> {
     @Override
-    public Class supportJavaTypeKey() {
+    public Class<?> supportJavaTypeKey() {
         return File.class;
     }
 
@@ -27,15 +27,15 @@ public class FileImageConverter implements Converter<File> {
     }
 
     @Override
-    public File convertToJavaData(CellData cellData, ExcelContentProperty contentProperty,
+    public File convertToJavaData(CellData<?> cellData, ExcelContentProperty contentProperty,
         GlobalConfiguration globalConfiguration) {
         throw new UnsupportedOperationException("Cannot convert images to file");
     }
 
     @Override
-    public CellData convertToExcelData(File value, ExcelContentProperty contentProperty,
+    public CellData<?> convertToExcelData(File value, ExcelContentProperty contentProperty,
         GlobalConfiguration globalConfiguration) throws IOException {
-        return new CellData(FileUtils.readFileToByteArray(value));
+        return new CellData<>(FileUtils.readFileToByteArray(value));
     }
 
 }

src/main/java/com/alibaba/excel/converters/floatconverter/FloatBooleanConverter.java

@@ -16,7 +16,7 @@ public class FloatBooleanConverter implements Converter<Float> {
     private static final Float ZERO = (float)0.0;
 
     @Override
-    public Class supportJavaTypeKey() {
+    public Class<?> supportJavaTypeKey() {
         return Float.class;
     }
 
@@ -26,7 +26,7 @@ public class FloatBooleanConverter implements Converter<Float> {
     }
 
     @Override
-    public Float convertToJavaData(CellData cellData, ExcelContentProperty contentProperty,
+    public Float convertToJavaData(CellData<?> cellData, ExcelContentProperty contentProperty,
         GlobalConfiguration globalConfiguration) {
         if (cellData.getBooleanValue()) {
             return ONE;
@@ -35,12 +35,12 @@ public class FloatBooleanConverter implements Converter<Float> {
     }
 
     @Override
-    public CellData convertToExcelData(Float value, ExcelContentProperty contentProperty,
+    public CellData<?> convertToExcelData(Float value, ExcelContentProperty contentProperty,
         GlobalConfiguration globalConfiguration) {
         if (ONE.equals(value)) {
-            return new CellData(Boolean.TRUE);
+            return new CellData<>(Boolean.TRUE);
         }
-        return new CellData(Boolean.FALSE);
+        return new CellData<>(Boolean.FALSE);
     }
 
 }

src/main/java/com/alibaba/excel/converters/floatconverter/FloatNumberConverter.java

@@ -16,7 +16,7 @@ import com.alibaba.excel.write.metadata.holder.WriteHolder;
 public class FloatNumberConverter implements Converter<Float> {
 
     @Override
-    public Class supportJavaTypeKey() {
+    public Class<?> supportJavaTypeKey() {
         return Float.class;
     }
 
@@ -26,7 +26,7 @@ public class FloatNumberConverter implements Converter<Float> {
     }
 
     @Override
-    public Float convertToJavaData(CellData cellData, ExcelContentProperty contentProperty,
+    public Float convertToJavaData(CellData<?> cellData, ExcelContentProperty contentProperty,
         GlobalConfiguration globalConfiguration) {
         return cellData.getNumberValue().floatValue();
     }

src/main/java/com/alibaba/excel/converters/floatconverter/FloatStringConverter.java

@@ -17,7 +17,7 @@ import com.alibaba.excel.util.NumberUtils;
 public class FloatStringConverter implements Converter<Float> {
 
     @Override
-    public Class supportJavaTypeKey() {
+    public Class<?> supportJavaTypeKey() {
         return Float.class;
     }
 
@@ -27,13 +27,13 @@ public class FloatStringConverter implements Converter<Float> {
     }
 
     @Override
-    public Float convertToJavaData(CellData cellData, ExcelContentProperty contentProperty,
+    public Float convertToJavaData(CellData<?> cellData, ExcelContentProperty contentProperty,
         GlobalConfiguration globalConfiguration) throws ParseException {
         return NumberUtils.parseFloat(cellData.getStringValue(), contentProperty);
     }
 
     @Override
-    public CellData convertToExcelData(Float value, ExcelContentProperty contentProperty,
+    public CellData<?> convertToExcelData(Float value, ExcelContentProperty contentProperty,
         GlobalConfiguration globalConfiguration) {
         return NumberUtils.formatToCellDataString(value, contentProperty);
     }

src/main/java/com/alibaba/excel/converters/inputstream/InputStreamImageConverter.java

@@ -17,7 +17,7 @@ import com.alibaba.excel.util.IoUtils;
  */
 public class InputStreamImageConverter implements Converter<InputStream> {
     @Override
-    public Class supportJavaTypeKey() {
+    public Class<?> supportJavaTypeKey() {
         return InputStream.class;
     }
 
@@ -27,15 +27,15 @@ public class InputStreamImageConverter implements Converter<InputStream> {
     }
 
     @Override
-    public InputStream convertToJavaData(CellData cellData, ExcelContentProperty contentProperty,
+    public InputStream convertToJavaData(CellData<?> cellData, ExcelContentProperty contentProperty,
         GlobalConfiguration globalConfiguration) {
         throw new UnsupportedOperationException("Cannot convert images to input stream");
     }
 
     @Override
-    public CellData convertToExcelData(InputStream value, ExcelContentProperty contentProperty,
+    public CellData<?> convertToExcelData(InputStream value, ExcelContentProperty contentProperty,
         GlobalConfiguration globalConfiguration) throws IOException {
-        return new CellData(IoUtils.toByteArray(value));
+        return new CellData<>(IoUtils.toByteArray(value));
     }
 
 }

src/main/java/com/alibaba/excel/converters/integer/IntegerBooleanConverter.java

@@ -16,7 +16,7 @@ public class IntegerBooleanConverter implements Converter<Integer> {
     private static final Integer ZERO = 0;
 
     @Override
-    public Class supportJavaTypeKey() {
+    public Class<?> supportJavaTypeKey() {
         return Integer.class;
     }
 
@@ -26,7 +26,7 @@ public class IntegerBooleanConverter implements Converter<Integer> {
     }
 
     @Override
-    public Integer convertToJavaData(CellData cellData, ExcelContentProperty contentProperty,
+    public Integer convertToJavaData(CellData<?> cellData, ExcelContentProperty contentProperty,
         GlobalConfiguration globalConfiguration) {
         if (cellData.getBooleanValue()) {
             return ONE;
@@ -35,12 +35,12 @@ public class IntegerBooleanConverter implements Converter<Integer> {
     }
 
     @Override
-    public CellData convertToExcelData(Integer value, ExcelContentProperty contentProperty,
+    public CellData<?> convertToExcelData(Integer value, ExcelContentProperty contentProperty,
         GlobalConfiguration globalConfiguration) {
         if (ONE.equals(value)) {
-            return new CellData(Boolean.TRUE);
+            return new CellData<>(Boolean.TRUE);
         }
-        return new CellData(Boolean.FALSE);
+        return new CellData<>(Boolean.FALSE);
     }
 
 }

src/main/java/com/alibaba/excel/converters/integer/IntegerNumberConverter.java

@@ -16,7 +16,7 @@ import com.alibaba.excel.write.metadata.holder.WriteHolder;
 public class IntegerNumberConverter implements Converter<Integer> {
 
     @Override
-    public Class supportJavaTypeKey() {
+    public Class<?> supportJavaTypeKey() {
         return Integer.class;
     }
 
@@ -26,7 +26,7 @@ public class IntegerNumberConverter implements Converter<Integer> {
     }
 
     @Override
-    public Integer convertToJavaData(CellData cellData, ExcelContentProperty contentProperty,
+    public Integer convertToJavaData(CellData<?> cellData, ExcelContentProperty contentProperty,
         GlobalConfiguration globalConfiguration) {
         return cellData.getNumberValue().intValue();
     }

src/main/java/com/alibaba/excel/converters/integer/IntegerStringConverter.java

@@ -17,7 +17,7 @@ import com.alibaba.excel.util.NumberUtils;
 public class IntegerStringConverter implements Converter<Integer> {
 
     @Override
-    public Class supportJavaTypeKey() {
+    public Class<?> supportJavaTypeKey() {
         return Integer.class;
     }
 
@@ -27,13 +27,13 @@ public class IntegerStringConverter implements Converter<Integer> {
     }
 
     @Override
-    public Integer convertToJavaData(CellData cellData, ExcelContentProperty contentProperty,
+    public Integer convertToJavaData(CellData<?> cellData, ExcelContentProperty contentProperty,
         GlobalConfiguration globalConfiguration) throws ParseException {
         return NumberUtils.parseInteger(cellData.getStringValue(), contentProperty);
     }
 
     @Override
-    public CellData convertToExcelData(Integer value, ExcelContentProperty contentProperty,
+    public CellData<?> convertToExcelData(Integer value, ExcelContentProperty contentProperty,
         GlobalConfiguration globalConfiguration) {
         return NumberUtils.formatToCellDataString(value, contentProperty);
     }

src/main/java/com/alibaba/excel/converters/shortconverter/ShortStringConverter.java

@@ -17,7 +17,7 @@ import com.alibaba.excel.util.NumberUtils;
 public class ShortStringConverter implements Converter<Short> {
 
     @Override
-    public Class supportJavaTypeKey() {
+    public Class<?> supportJavaTypeKey() {
         return Short.class;
     }
 
@@ -27,13 +27,13 @@ public class ShortStringConverter implements Converter<Short> {
     }
 
     @Override
-    public Short convertToJavaData(CellData cellData, ExcelContentProperty contentProperty,
+    public Short convertToJavaData(CellData<?>cellData, ExcelContentProperty contentProperty,
         GlobalConfiguration globalConfiguration) throws ParseException {
         return NumberUtils.parseShort(cellData.getStringValue(), contentProperty);
     }
 
     @Override
-    public CellData convertToExcelData(Short value, ExcelContentProperty contentProperty,
+    public CellData<?>convertToExcelData(Short value, ExcelContentProperty contentProperty,
         GlobalConfiguration globalConfiguration) {
         return NumberUtils.formatToCellDataString(value, contentProperty);
     }

src/main/java/com/alibaba/excel/converters/string/StringBooleanConverter.java

@@ -14,7 +14,7 @@ import com.alibaba.excel.metadata.property.ExcelContentProperty;
 public class StringBooleanConverter implements Converter<String> {
 
     @Override
-    public Class supportJavaTypeKey() {
+    public Class<?> supportJavaTypeKey() {
         return String.class;
     }
 
@@ -24,15 +24,15 @@ public class StringBooleanConverter implements Converter<String> {
     }
 
     @Override
-    public String convertToJavaData(CellData cellData, ExcelContentProperty contentProperty,
+    public String convertToJavaData(CellData<?> cellData, ExcelContentProperty contentProperty,
         GlobalConfiguration globalConfiguration) {
         return cellData.getBooleanValue().toString();
     }
 
     @Override
-    public CellData convertToExcelData(String value, ExcelContentProperty contentProperty,
+    public CellData<?> convertToExcelData(String value, ExcelContentProperty contentProperty,
         GlobalConfiguration globalConfiguration) {
-        return new CellData(Boolean.valueOf(value));
+        return new CellData<>(Boolean.valueOf(value));
     }
 
 }

src/main/java/com/alibaba/excel/converters/string/StringErrorConverter.java

@@ -13,7 +13,7 @@ import com.alibaba.excel.metadata.property.ExcelContentProperty;
  */
 public class StringErrorConverter implements Converter<String> {
     @Override
-    public Class supportJavaTypeKey() {
+    public Class<String> supportJavaTypeKey() {
         return String.class;
     }
 
@@ -23,15 +23,15 @@ public class StringErrorConverter implements Converter<String> {
     }
 
     @Override
-    public String convertToJavaData(CellData cellData, ExcelContentProperty contentProperty,
+    public String convertToJavaData(CellData<?> cellData, ExcelContentProperty contentProperty,
         GlobalConfiguration globalConfiguration) {
         return cellData.getStringValue();
     }
 
     @Override
-    public CellData convertToExcelData(String value, ExcelContentProperty contentProperty,
+    public CellData<?> convertToExcelData(String value, ExcelContentProperty contentProperty,
         GlobalConfiguration globalConfiguration) {
-        return new CellData(CellDataTypeEnum.ERROR, value);
+        return new CellData<>(CellDataTypeEnum.ERROR, value);
     }
 
 }

src/main/java/com/alibaba/excel/converters/string/StringImageConverter.java

@@ -17,7 +17,7 @@ import com.alibaba.excel.util.FileUtils;
  */
 public class StringImageConverter implements Converter<String> {
     @Override
-    public Class supportJavaTypeKey() {
+    public Class<?> supportJavaTypeKey() {
         return String.class;
     }
 
@@ -27,15 +27,15 @@ public class StringImageConverter implements Converter<String> {
     }
 
     @Override
-    public String convertToJavaData(CellData cellData, ExcelContentProperty contentProperty,
+    public String convertToJavaData(CellData<?> cellData, ExcelContentProperty contentProperty,
         GlobalConfiguration globalConfiguration) {
         throw new UnsupportedOperationException("Cannot convert images to string");
     }
 
     @Override
-    public CellData convertToExcelData(String value, ExcelContentProperty contentProperty,
+    public CellData<?> convertToExcelData(String value, ExcelContentProperty contentProperty,
         GlobalConfiguration globalConfiguration) throws IOException {
-        return new CellData(FileUtils.readFileToByteArray(new File(value)));
+        return new CellData<>(FileUtils.readFileToByteArray(new File(value)));
     }
 
 }

src/main/java/com/alibaba/excel/converters/string/StringNumberConverter.java

@@ -22,7 +22,7 @@ import com.alibaba.excel.util.StringUtils;
 public class StringNumberConverter implements Converter<String> {
 
     @Override
-    public Class supportJavaTypeKey() {
+    public Class<?> supportJavaTypeKey() {
         return String.class;
     }
 
@@ -32,7 +32,7 @@ public class StringNumberConverter implements Converter<String> {
     }
 
     @Override
-    public String convertToJavaData(CellData cellData, ExcelContentProperty contentProperty,
+    public String convertToJavaData(CellData<?> cellData, ExcelContentProperty contentProperty,
         GlobalConfiguration globalConfiguration) {
         // If there are "DateTimeFormat", read as date
         if (contentProperty != null && contentProperty.getDateTimeFormatProperty() != null) {
@@ -55,8 +55,8 @@ public class StringNumberConverter implements Converter<String> {
     }
 
     @Override
-    public CellData convertToExcelData(String value, ExcelContentProperty contentProperty,
+    public CellData<?> convertToExcelData(String value, ExcelContentProperty contentProperty,
         GlobalConfiguration globalConfiguration) {
-        return new CellData(new BigDecimal(value));
+        return new CellData<>(new BigDecimal(value));
     }
 }

src/main/java/com/alibaba/excel/converters/string/StringStringConverter.java

@@ -13,7 +13,7 @@ import com.alibaba.excel.metadata.property.ExcelContentProperty;
  */
 public class StringStringConverter implements Converter<String> {
     @Override
-    public Class supportJavaTypeKey() {
+    public Class<?> supportJavaTypeKey() {
         return String.class;
     }
 
@@ -23,15 +23,15 @@ public class StringStringConverter implements Converter<String> {
     }
 
     @Override
-    public String convertToJavaData(CellData cellData, ExcelContentProperty contentProperty,
+    public String convertToJavaData(CellData<?> cellData, ExcelContentProperty contentProperty,
         GlobalConfiguration globalConfiguration) {
         return cellData.getStringValue();
     }
 
     @Override
-    public CellData convertToExcelData(String value, ExcelContentProperty contentProperty,
+    public CellData<?> convertToExcelData(String value, ExcelContentProperty contentProperty,
         GlobalConfiguration globalConfiguration) {
-        return new CellData(value);
+        return new CellData<>(value);
     }
 
 }

src/main/java/com/alibaba/excel/converters/url/UrlImageConverter.java

@@ -19,7 +19,7 @@ import com.alibaba.excel.util.IoUtils;
  */
 public class UrlImageConverter implements Converter<URL> {
     @Override
-    public Class supportJavaTypeKey() {
+    public Class<?> supportJavaTypeKey() {
         return URL.class;
     }
 
@@ -29,19 +29,19 @@ public class UrlImageConverter implements Converter<URL> {
     }
 
     @Override
-    public URL convertToJavaData(CellData cellData, ExcelContentProperty contentProperty,
+    public URL convertToJavaData(CellData<?> cellData, ExcelContentProperty contentProperty,
         GlobalConfiguration globalConfiguration) {
         throw new UnsupportedOperationException("Cannot convert images to url.");
     }
 
     @Override
-    public CellData convertToExcelData(URL value, ExcelContentProperty contentProperty,
+    public CellData<?> convertToExcelData(URL value, ExcelContentProperty contentProperty,
         GlobalConfiguration globalConfiguration) throws IOException {
         InputStream inputStream = null;
         try {
             inputStream = value.openStream();
             byte[] bytes = IoUtils.toByteArray(inputStream);
-            return new CellData(bytes);
+            return new CellData<>(bytes);
         } finally {
             if (inputStream != null) {
                 inputStream.close();

src/main/java/com/alibaba/excel/exception/ExcelDataConvertException.java

@@ -4,11 +4,16 @@ import com.alibaba.excel.metadata.CellData;
 import com.alibaba.excel.metadata.property.ExcelContentProperty;
 import com.alibaba.excel.write.builder.ExcelWriterBuilder;
 
+import lombok.Getter;
+import lombok.Setter;
+
 /**
  * Data convert exception
  *
  * @author Jiaju Zhuang
  */
+@Getter
+@Setter
 public class ExcelDataConvertException extends RuntimeException {
     /**
      * NotNull.
@@ -21,7 +26,7 @@ public class ExcelDataConvertException extends RuntimeException {
     /**
      * NotNull.
      */
-    private CellData cellData;
+    private CellData<?> cellData;
     /**
      * Nullable.Only when the header is configured and when the class header is used is not null.
      *
@@ -47,35 +52,4 @@ public class ExcelDataConvertException extends RuntimeException {
         this.excelContentProperty = excelContentProperty;
     }
 
-    public Integer getRowIndex() {
-        return rowIndex;
-    }
-
-    public void setRowIndex(Integer rowIndex) {
-        this.rowIndex = rowIndex;
-    }
-
-    public Integer getColumnIndex() {
-        return columnIndex;
-    }
-
-    public void setColumnIndex(Integer columnIndex) {
-        this.columnIndex = columnIndex;
-    }
-
-    public ExcelContentProperty getExcelContentProperty() {
-        return excelContentProperty;
-    }
-
-    public void setExcelContentProperty(ExcelContentProperty excelContentProperty) {
-        this.excelContentProperty = excelContentProperty;
-    }
-
-    public CellData getCellData() {
-        return cellData;
-    }
-
-    public void setCellData(CellData cellData) {
-        this.cellData = cellData;
-    }
 }

src/main/java/com/alibaba/excel/metadata/CellData.java

@@ -122,6 +122,16 @@ public class CellData<T> extends AbstractCell {
         this.formula = Boolean.FALSE;
     }
 
+    public CellData(Date dateValue) {
+        if (dateValue == null) {
+            throw new IllegalArgumentException("DateValue can not be null");
+        }
+        this.type = CellDataTypeEnum.DATE;
+        this.dateValue = dateValue;
+        this.formula = Boolean.FALSE;
+    }
+
+
     public CellData(CellDataTypeEnum type) {
         if (type == null) {
             throw new IllegalArgumentException("Type can not be null");
@@ -158,37 +168,37 @@ public class CellData<T> extends AbstractCell {
         }
     }
 
-    public static CellData newEmptyInstance() {
+    public static CellData<?> newEmptyInstance() {
         return newEmptyInstance(null, null);
     }
 
-    public static CellData newEmptyInstance(Integer rowIndex, Integer columnIndex) {
+    public static CellData<?> newEmptyInstance(Integer rowIndex, Integer columnIndex) {
-        CellData cellData = new CellData(CellDataTypeEnum.EMPTY);
+        CellData<?> cellData = new CellData<>(CellDataTypeEnum.EMPTY);
         cellData.setRowIndex(rowIndex);
         cellData.setColumnIndex(columnIndex);
         return cellData;
     }
 
-    public static CellData newInstance(Boolean booleanValue) {
+    public static CellData<?> newInstance(Boolean booleanValue) {
         return newInstance(booleanValue, null, null);
     }
 
-    public static CellData newInstance(Boolean booleanValue, Integer rowIndex, Integer columnIndex) {
+    public static CellData<?> newInstance(Boolean booleanValue, Integer rowIndex, Integer columnIndex) {
-        CellData cellData = new CellData(booleanValue);
+        CellData<?> cellData = new CellData<>(booleanValue);
         cellData.setRowIndex(rowIndex);
         cellData.setColumnIndex(columnIndex);
         return cellData;
     }
 
-    public static CellData newInstance(String stringValue, Integer rowIndex, Integer columnIndex) {
+    public static CellData<?> newInstance(String stringValue, Integer rowIndex, Integer columnIndex) {
-        CellData cellData = new CellData(stringValue);
+        CellData<?> cellData = new CellData<>(stringValue);
         cellData.setRowIndex(rowIndex);
         cellData.setColumnIndex(columnIndex);
         return cellData;
     }
 
-    public static CellData newInstance(BigDecimal numberValue, Integer rowIndex, Integer columnIndex) {
+    public static CellData<?> newInstance(BigDecimal numberValue, Integer rowIndex, Integer columnIndex) {
-        CellData cellData = new CellData(numberValue);
+        CellData<?> cellData = new CellData<>(numberValue);
         cellData.setRowIndex(rowIndex);
         cellData.setColumnIndex(columnIndex);
         return cellData;

src/main/java/com/alibaba/excel/read/metadata/holder/ReadSheetHolder.java

@@ -51,7 +51,7 @@ public class ReadSheetHolder extends AbstractReadHolder {
     /**
      * Current CellData
      */
-    private CellData tempCellData;
+    private CellData<?> tempCellData;
 
     public ReadSheetHolder(ReadSheet readSheet, ReadWorkbookHolder readWorkbookHolder) {
         super(readSheet, readWorkbookHolder, readWorkbookHolder.getReadWorkbook().getConvertAllFiled());
@@ -135,11 +135,11 @@ public class ReadSheetHolder extends AbstractReadHolder {
         this.rowIndex = rowIndex;
     }
 
-    public CellData getTempCellData() {
+    public CellData<?> getTempCellData() {
         return tempCellData;
     }
 
-    public void setTempCellData(CellData tempCellData) {
+    public void setTempCellData(CellData<?> tempCellData) {
         this.tempCellData = tempCellData;
     }
 

src/main/java/com/alibaba/excel/util/StyleUtil.java

@@ -1,5 +1,8 @@
 package com.alibaba.excel.util;
 
+import com.alibaba.excel.write.metadata.style.WriteCellStyle;
+import com.alibaba.excel.write.metadata.style.WriteFont;
+
 import org.apache.poi.ss.usermodel.BorderStyle;
 import org.apache.poi.ss.usermodel.CellStyle;
 import org.apache.poi.ss.usermodel.FillPatternType;
@@ -8,15 +11,17 @@ import org.apache.poi.ss.usermodel.HorizontalAlignment;
 import org.apache.poi.ss.usermodel.IndexedColors;
 import org.apache.poi.ss.usermodel.VerticalAlignment;
 import org.apache.poi.ss.usermodel.Workbook;
-
+import org.apache.poi.xssf.streaming.SXSSFSheet;
-import com.alibaba.excel.write.metadata.style.WriteCellStyle;
+import org.apache.poi.xssf.usermodel.XSSFCellStyle;
-import com.alibaba.excel.write.metadata.style.WriteFont;
 
 /**
  * @author jipengfei
  */
 public class StyleUtil {
 
+    public static short XSSF_DEFAULT_STYLE = 0;
+    public static short HSSF_DEFAULT_STYLE = 15;
+
     private StyleUtil() {}
 
     /**
@@ -183,4 +188,13 @@ public class StyleUtil {
         }
     }
 
+    public static boolean isDefaultStyle(CellStyle cellStyle) {
+        if (cellStyle == null) {
+            return true;
+        }
+        if (cellStyle instanceof XSSFCellStyle) {
+            return cellStyle.getIndex() == XSSF_DEFAULT_STYLE;
+        }
+        return cellStyle.getIndex() == HSSF_DEFAULT_STYLE;
+    }
 }

src/main/java/com/alibaba/excel/util/WriteHandlerUtils.java

@@ -4,9 +4,6 @@ import java.util.ArrayList;
 import java.util.List;
 import java.util.Map;
 
-import org.apache.poi.ss.usermodel.Cell;
-import org.apache.poi.ss.usermodel.Row;
-
 import com.alibaba.excel.context.WriteContext;
 import com.alibaba.excel.metadata.CellData;
 import com.alibaba.excel.metadata.Head;
@@ -16,6 +13,9 @@ import com.alibaba.excel.write.handler.SheetWriteHandler;
 import com.alibaba.excel.write.handler.WorkbookWriteHandler;
 import com.alibaba.excel.write.handler.WriteHandler;
 
+import org.apache.poi.ss.usermodel.Cell;
+import org.apache.poi.ss.usermodel.Row;
+
 /**
  * Write handler utils
  *
@@ -25,7 +25,6 @@ public class WriteHandlerUtils {
 
     private WriteHandlerUtils() {}
 
-
     public static void beforeWorkbookCreate(WriteContext writeContext) {
         beforeWorkbookCreate(writeContext, false);
     }
@@ -37,7 +36,7 @@ public class WriteHandlerUtils {
         }
         for (WriteHandler writeHandler : handlerList) {
             if (writeHandler instanceof WorkbookWriteHandler) {
-                ((WorkbookWriteHandler) writeHandler).beforeWorkbookCreate();
+                ((WorkbookWriteHandler)writeHandler).beforeWorkbookCreate();
             }
         }
     }
@@ -53,7 +52,7 @@ public class WriteHandlerUtils {
         }
         for (WriteHandler writeHandler : handlerList) {
             if (writeHandler instanceof WorkbookWriteHandler) {
-                ((WorkbookWriteHandler) writeHandler).afterWorkbookCreate(writeContext.writeWorkbookHolder());
+                ((WorkbookWriteHandler)writeHandler).afterWorkbookCreate(writeContext.writeWorkbookHolder());
             }
         }
     }
@@ -66,7 +65,7 @@ public class WriteHandlerUtils {
         }
         for (WriteHandler writeHandler : handlerList) {
             if (writeHandler instanceof WorkbookWriteHandler) {
-                ((WorkbookWriteHandler) writeHandler).afterWorkbookDispose(writeContext.writeWorkbookHolder());
+                ((WorkbookWriteHandler)writeHandler).afterWorkbookDispose(writeContext.writeWorkbookHolder());
             }
         }
     }
@@ -82,13 +81,12 @@ public class WriteHandlerUtils {
         }
         for (WriteHandler writeHandler : handlerList) {
             if (writeHandler instanceof SheetWriteHandler) {
-                ((SheetWriteHandler) writeHandler).beforeSheetCreate(writeContext.writeWorkbookHolder(),
+                ((SheetWriteHandler)writeHandler).beforeSheetCreate(writeContext.writeWorkbookHolder(),
                     writeContext.writeSheetHolder());
             }
         }
     }
 
-
     public static void afterSheetCreate(WriteContext writeContext) {
         afterSheetCreate(writeContext, false);
     }
@@ -100,7 +98,7 @@ public class WriteHandlerUtils {
         }
         for (WriteHandler writeHandler : handlerList) {
             if (writeHandler instanceof SheetWriteHandler) {
-                ((SheetWriteHandler) writeHandler).afterSheetCreate(writeContext.writeWorkbookHolder(),
+                ((SheetWriteHandler)writeHandler).afterSheetCreate(writeContext.writeWorkbookHolder(),
                     writeContext.writeSheetHolder());
             }
         }
@@ -119,7 +117,7 @@ public class WriteHandlerUtils {
         }
         for (WriteHandler writeHandler : handlerList) {
             if (writeHandler instanceof CellWriteHandler) {
-                ((CellWriteHandler) writeHandler).beforeCellCreate(writeContext.writeSheetHolder(),
+                ((CellWriteHandler)writeHandler).beforeCellCreate(writeContext.writeSheetHolder(),
                     writeContext.writeTableHolder(), row, head, columnIndex, relativeRowIndex, isHead);
             }
         }
@@ -134,7 +132,7 @@ public class WriteHandlerUtils {
         }
         for (WriteHandler writeHandler : handlerList) {
             if (writeHandler instanceof CellWriteHandler) {
-                ((CellWriteHandler) writeHandler).afterCellCreate(writeContext.writeSheetHolder(),
+                ((CellWriteHandler)writeHandler).afterCellCreate(writeContext.writeSheetHolder(),
                     writeContext.writeTableHolder(), cell, head, relativeRowIndex, isHead);
             }
         }
@@ -149,7 +147,7 @@ public class WriteHandlerUtils {
         }
         for (WriteHandler writeHandler : handlerList) {
             if (writeHandler instanceof CellWriteHandler) {
-                ((CellWriteHandler) writeHandler).afterCellDataConverted(writeContext.writeSheetHolder(),
+                ((CellWriteHandler)writeHandler).afterCellDataConverted(writeContext.writeSheetHolder(),
                     writeContext.writeTableHolder(), cellData, cell, head, relativeRowIndex, isHead);
             }
         }
@@ -158,7 +156,7 @@ public class WriteHandlerUtils {
     public static void afterCellDispose(WriteContext writeContext, CellData cellData, Cell cell, Head head,
         Integer relativeRowIndex, Boolean isHead) {
         List<CellData<?>> cellDataList = new ArrayList<>();
-        if (cell != null) {
+        if (cellData != null) {
             cellDataList.add(cellData);
         }
         afterCellDispose(writeContext, cellDataList, cell, head, relativeRowIndex, isHead);
@@ -173,7 +171,7 @@ public class WriteHandlerUtils {
         }
         for (WriteHandler writeHandler : handlerList) {
             if (writeHandler instanceof CellWriteHandler) {
-                ((CellWriteHandler) writeHandler).afterCellDispose(writeContext.writeSheetHolder(),
+                ((CellWriteHandler)writeHandler).afterCellDispose(writeContext.writeSheetHolder(),
                     writeContext.writeTableHolder(), cellDataList, cell, head, relativeRowIndex, isHead);
             }
         }
@@ -190,7 +188,7 @@ public class WriteHandlerUtils {
         }
         for (WriteHandler writeHandler : handlerList) {
             if (writeHandler instanceof RowWriteHandler) {
-                ((RowWriteHandler) writeHandler).beforeRowCreate(writeContext.writeSheetHolder(),
+                ((RowWriteHandler)writeHandler).beforeRowCreate(writeContext.writeSheetHolder(),
                     writeContext.writeTableHolder(), rowIndex, relativeRowIndex, isHead);
             }
         }
@@ -203,7 +201,7 @@ public class WriteHandlerUtils {
         }
         for (WriteHandler writeHandler : handlerList) {
             if (writeHandler instanceof RowWriteHandler) {
-                ((RowWriteHandler) writeHandler).afterRowCreate(writeContext.writeSheetHolder(),
+                ((RowWriteHandler)writeHandler).afterRowCreate(writeContext.writeSheetHolder(),
                     writeContext.writeTableHolder(), row, relativeRowIndex, isHead);
             }
         }
@@ -217,7 +215,7 @@ public class WriteHandlerUtils {
         }
         for (WriteHandler writeHandler : handlerList) {
             if (writeHandler instanceof RowWriteHandler) {
-                ((RowWriteHandler) writeHandler).afterRowDispose(writeContext.writeSheetHolder(),
+                ((RowWriteHandler)writeHandler).afterRowDispose(writeContext.writeSheetHolder(),
                     writeContext.writeTableHolder(), row, relativeRowIndex, isHead);
             }
         }

src/main/java/com/alibaba/excel/write/executor/AbstractExcelWriteExecutor.java

@@ -30,15 +30,16 @@ public abstract class AbstractExcelWriteExecutor implements ExcelWriteExecutor {
         this.writeContext = writeContext;
     }
 
-    protected CellData converterAndSet(WriteHolder currentWriteHolder, Class clazz, Cell cell, Object value,
+    protected CellData<?> converterAndSet(WriteHolder currentWriteHolder, Class<?> clazz, CellDataTypeEnum targetType,
+        Cell cell, Object value,
         ExcelContentProperty excelContentProperty, Head head, Integer relativeRowIndex) {
         if (value == null) {
-            return new CellData(CellDataTypeEnum.EMPTY);
+            return new CellData<>(CellDataTypeEnum.EMPTY);
         }
         if (value instanceof String && currentWriteHolder.globalConfiguration().getAutoTrim()) {
             value = ((String)value).trim();
         }
-        CellData cellData = convert(currentWriteHolder, clazz, cell, value, excelContentProperty);
+        CellData<?> cellData = convert(currentWriteHolder, clazz, targetType, cell, value, excelContentProperty);
         if (cellData.getFormula() != null && cellData.getFormula()) {
             cell.setCellFormula(cellData.getFormulaValue());
         }
@@ -71,14 +72,15 @@ public abstract class AbstractExcelWriteExecutor implements ExcelWriteExecutor {
         }
     }
 
-    protected CellData convert(WriteHolder currentWriteHolder, Class clazz, Cell cell, Object value,
+    protected CellData<?> convert(WriteHolder currentWriteHolder, Class<?> clazz, CellDataTypeEnum targetType,
-        ExcelContentProperty excelContentProperty) {
+        Cell cell,
+        Object value, ExcelContentProperty excelContentProperty) {
         if (value == null) {
-            return new CellData(CellDataTypeEnum.EMPTY);
+            return new CellData<>(CellDataTypeEnum.EMPTY);
         }
         // This means that the user has defined the data.
         if (value instanceof CellData) {
-            CellData cellDataValue = (CellData)value;
+            CellData<?> cellDataValue = (CellData<?>)value;
             if (cellDataValue.getType() != null) {
                 return cellDataValue;
             } else {
@@ -87,8 +89,8 @@ public abstract class AbstractExcelWriteExecutor implements ExcelWriteExecutor {
                     return cellDataValue;
                 }
             }
-            CellData cellDataReturn = doConvert(currentWriteHolder, cellDataValue.getData().getClass(), cell,
+            CellData<?> cellDataReturn = doConvert(currentWriteHolder, cellDataValue.getData().getClass(), targetType,
-                cellDataValue.getData(), excelContentProperty);
+                cell, cellDataValue.getData(), excelContentProperty);
             // The formula information is subject to user input
             if (cellDataValue.getFormula() != null) {
                 cellDataReturn.setFormula(cellDataValue.getFormula());
@@ -96,41 +98,40 @@ public abstract class AbstractExcelWriteExecutor implements ExcelWriteExecutor {
             }
             return cellDataReturn;
         }
-        return doConvert(currentWriteHolder, clazz, cell, value, excelContentProperty);
+        return doConvert(currentWriteHolder, clazz, targetType, cell, value, excelContentProperty);
     }
 
-    private CellData doConvert(WriteHolder currentWriteHolder, Class clazz, Cell cell, Object value,
+    private CellData<?> doConvert(WriteHolder currentWriteHolder, Class<?> clazz, CellDataTypeEnum targetType,
-        ExcelContentProperty excelContentProperty) {
+        Cell cell, Object value, ExcelContentProperty excelContentProperty) {
         Converter converter = null;
         if (excelContentProperty != null) {
             converter = excelContentProperty.getConverter();
         }
         if (converter == null) {
-            converter = currentWriteHolder.converterMap().get(ConverterKeyBuild.buildKey(clazz));
+            converter = currentWriteHolder.converterMap().get(ConverterKeyBuild.buildKey(clazz, targetType));
         }
         if (converter == null) {
             throw new ExcelDataConvertException(cell.getRow().getRowNum(), cell.getColumnIndex(),
-                new CellData(CellDataTypeEnum.EMPTY), excelContentProperty,
+                new CellData<>(CellDataTypeEnum.EMPTY), excelContentProperty,
                 "Can not find 'Converter' support class " + clazz.getSimpleName() + ".");
         }
-        CellData cellData;
+        CellData<?> cellData;
         try {
-            cellData =
+            cellData = converter.convertToExcelData(value, excelContentProperty, currentWriteHolder);
-                converter.convertToExcelData(value, excelContentProperty, currentWriteHolder);
         } catch (Exception e) {
             throw new ExcelDataConvertException(cell.getRow().getRowNum(), cell.getColumnIndex(),
-                new CellData(CellDataTypeEnum.EMPTY), excelContentProperty,
+                new CellData<>(CellDataTypeEnum.EMPTY), excelContentProperty,
                 "Convert data:" + value + " error,at row:" + cell.getRow().getRowNum(), e);
         }
         if (cellData == null || cellData.getType() == null) {
             throw new ExcelDataConvertException(cell.getRow().getRowNum(), cell.getColumnIndex(),
-                new CellData(CellDataTypeEnum.EMPTY), excelContentProperty,
+                new CellData<>(CellDataTypeEnum.EMPTY), excelContentProperty,
                 "Convert data:" + value + " return null,at row:" + cell.getRow().getRowNum());
         }
         return cellData;
     }
 
-    private void setImageValue(CellData cellData, Cell cell) {
+    private void setImageValue(CellData<?> cellData, Cell cell) {
         Sheet sheet = cell.getSheet();
         int index = sheet.getWorkbook().addPicture(cellData.getImageValue(), HSSFWorkbook.PICTURE_TYPE_PNG);
         Drawing drawing = sheet.getDrawingPatriarch();

src/main/java/com/alibaba/excel/write/executor/ExcelWriteAddExecutor.java

@@ -114,8 +114,7 @@ public class ExcelWriteAddExecutor extends AbstractExcelWriteExecutor {
         WriteHandlerUtils.afterCellCreate(writeContext, cell, head, relativeRowIndex, Boolean.FALSE);
         Object value = oneRowData.get(dataIndex);
         CellData cellData = converterAndSet(writeContext.currentWriteHolder(), value == null ? null : value.getClass(),
-            cell, value, null, head, relativeRowIndex);
+            null, cell, value, null, head, relativeRowIndex);
-        writeContext.writeSheetHolder().setLastRowIndex(cellData.getRowIndex());
         WriteHandlerUtils.afterCellDispose(writeContext, cellData, cell, head, relativeRowIndex, Boolean.FALSE);
     }
 
@@ -142,8 +141,9 @@ public class ExcelWriteAddExecutor extends AbstractExcelWriteExecutor {
                 Cell cell = WorkBookUtil.createCell(row, cellIndex);
                 WriteHandlerUtils.afterCellCreate(writeContext, cell, head, relativeRowIndex, Boolean.FALSE);
                 Object value = beanMap.get(name);
-                CellData cellData = converterAndSet(currentWriteHolder, excelContentProperty.getField().getType(), cell,
+                CellData<?> cellData = converterAndSet(currentWriteHolder, excelContentProperty.getField().getType(),
-                    value, excelContentProperty, head, relativeRowIndex);
+                    null,
+                    cell, value, excelContentProperty, head, relativeRowIndex);
                 WriteHandlerUtils.afterCellDispose(writeContext, cellData, cell, head, relativeRowIndex, Boolean.FALSE);
                 beanMapHandledSet.add(name);
             }
@@ -167,7 +167,7 @@ public class ExcelWriteAddExecutor extends AbstractExcelWriteExecutor {
             WriteHandlerUtils.beforeCellCreate(writeContext, row, null, cellIndex, relativeRowIndex, Boolean.FALSE);
             Cell cell = WorkBookUtil.createCell(row, cellIndex);
             WriteHandlerUtils.afterCellCreate(writeContext, cell, null, relativeRowIndex, Boolean.FALSE);
-            CellData cellData = converterAndSet(currentWriteHolder, value == null ? null : value.getClass(), cell,
+            CellData<?> cellData = converterAndSet(currentWriteHolder, value == null ? null : value.getClass(), null, cell,
                 value, null, null, relativeRowIndex);
             WriteHandlerUtils.afterCellDispose(writeContext, cellData, cell, null, relativeRowIndex, Boolean.FALSE);
         }

src/main/java/com/alibaba/excel/write/executor/ExcelWriteFillExecutor.java

@@ -198,8 +198,8 @@ public class ExcelWriteFillExecutor extends AbstractExcelWriteExecutor {
                     continue;
                 }
                 Object value = dataMap.get(variable);
-                CellData cellData = converterAndSet(writeSheetHolder, value == null ? null : value.getClass(), cell,
+                CellData<?> cellData = converterAndSet(writeSheetHolder, value == null ? null : value.getClass(), null,
-                    value, fieldNameContentPropertyMap.get(variable), null, relativeRowIndex);
+                    cell, value, fieldNameContentPropertyMap.get(variable), null, relativeRowIndex);
                 WriteHandlerUtils.afterCellDispose(writeContext, cellData, cell, null, relativeRowIndex, Boolean.FALSE);
             } else {
                 StringBuilder cellValueBuild = new StringBuilder();
@@ -211,8 +211,8 @@ public class ExcelWriteFillExecutor extends AbstractExcelWriteExecutor {
                         continue;
                     }
                     Object value = dataMap.get(variable);
-                    CellData cellData = convert(writeSheetHolder, value == null ? null : value.getClass(), cell, value,
+                    CellData<?> cellData = convert(writeSheetHolder, value == null ? null : value.getClass(),
-                        fieldNameContentPropertyMap.get(variable));
+                        CellDataTypeEnum.STRING, cell, value, fieldNameContentPropertyMap.get(variable));
                     cellDataList.add(cellData);
                     CellDataTypeEnum type = cellData.getType();
                     if (type != null) {

src/main/java/com/alibaba/excel/write/handler/impl/DimensionWorkbookWriteHandler.java

@@ -69,8 +69,13 @@ public class DimensionWorkbookWriteHandler implements WorkbookWriteHandler {
                     headSize--;
                 }
             }
+            Integer lastRowIndex = writeSheetHolder.getLastRowIndex();
+            if (lastRowIndex == null) {
+                lastRowIndex = 0;
+            }
+
             ctWorksheet.getDimension().setRef(
-                "A1:" + CellReference.convertNumToColString(headSize) + (writeSheetHolder.getLastRowIndex() + 1));
+                "A1:" + CellReference.convertNumToColString(headSize) + (lastRowIndex + 1));
         }
     }
 }

src/main/java/com/alibaba/excel/write/handler/impl/FillDataFormatCellWriteHandler.java

@@ -10,6 +10,7 @@ import com.alibaba.excel.event.Order;
 import com.alibaba.excel.metadata.CellData;
 import com.alibaba.excel.metadata.Head;
 import com.alibaba.excel.util.DateUtils;
+import com.alibaba.excel.util.StyleUtil;
 import com.alibaba.excel.write.handler.CellWriteHandler;
 import com.alibaba.excel.write.metadata.holder.WriteSheetHolder;
 import com.alibaba.excel.write.metadata.holder.WriteTableHolder;
@@ -46,7 +47,7 @@ public class FillDataFormatCellWriteHandler implements CellWriteHandler, Order {
         }
         CellData<?> cellData = cellDataList.get(0);
         CellStyle cellStyle = cell.getCellStyle();
-        if (cellStyle == null) {
+        if (cellStyle == null || StyleUtil.isDefaultStyle(cellStyle)) {
             if (cellData.getType() == CellDataTypeEnum.DATE) {
                 cell.setCellStyle(getDefaultDateCellStyle(writeSheetHolder));
             }

src/main/java/com/alibaba/excel/write/metadata/holder/WriteWorkbookHolder.java

@@ -10,6 +10,7 @@ import java.io.OutputStream;
 import java.util.HashMap;
 import java.util.Map;
 
+import com.alibaba.excel.constant.BuiltinFormats;
 import com.alibaba.excel.enums.HolderEnum;
 import com.alibaba.excel.exception.ExcelGenerateException;
 import com.alibaba.excel.support.ExcelTypeEnum;
@@ -211,7 +212,7 @@ public class WriteWorkbookHolder extends AbstractWriteHolder {
      */
     public Short getDataFormat(String format) {
         if (StringUtils.isEmpty(format)) {
-            return 0;
+            return BuiltinFormats.GENERAL;
         }
         Short dataFormat = dataFormatCache.get(format);
         if (dataFormat != null) {

src/main/java/com/alibaba/excel/write/property/ExcelWriteHeadProperty.java

@@ -102,14 +102,6 @@ public class ExcelWriteHeadProperty extends ExcelHeadProperty {
             headData.setContentFontProperty(FontProperty.build(contentFontStyle));
 
             headData.setLoopMergeProperty(LoopMergeProperty.build(field.getAnnotation(ContentLoopMerge.class)));
-            // If have @NumberFormat, 'NumberStringConverter' is specified by default
-            if (excelContentPropertyData.getConverter() == null) {
-                NumberFormat numberFormat = field.getAnnotation(NumberFormat.class);
-                if (numberFormat != null) {
-                    excelContentPropertyData.setConverter(DefaultConverterLoader.loadAllConverter()
-                        .get(ConverterKeyBuild.buildKey(field.getType(), CellDataTypeEnum.STRING)));
-                }
-            }
         }
     }
 

src/main/java/com/alibaba/excel/write/style/AbstractVerticalCellStyleStrategy.java

@@ -42,7 +42,7 @@ public abstract class AbstractVerticalCellStyleStrategy extends AbstractCellStyl
         }
         WriteCellStyle headCellStyle = headCellStyle(head);
         if (headCellStyle == null) {
-            headCellStyleCache.put(columnIndex, null);
+            headCellStyleCache.put(columnIndex, StyleUtil.buildHeadCellStyle(workbook, null));
         } else {
             CellStyle cellStyle = StyleUtil.buildHeadCellStyle(workbook, headCellStyle);
             headCellStyleCache.put(columnIndex, cellStyle);
@@ -65,7 +65,7 @@ public abstract class AbstractVerticalCellStyleStrategy extends AbstractCellStyl
         }
         WriteCellStyle contentCellStyle = contentCellStyle(cell, head, relativeRowIndex);
         if (contentCellStyle == null) {
-            contentCellStyleCache.put(columnIndex, null);
+            contentCellStyleCache.put(columnIndex, StyleUtil.buildContentCellStyle(workbook, null));
         } else {
             CellStyle cellStyle = StyleUtil.buildContentCellStyle(workbook, contentCellStyle);
             contentCellStyleCache.put(columnIndex, cellStyle);

src/main/java/com/alibaba/excel/write/style/HorizontalCellStyleStrategy.java

@@ -39,7 +39,7 @@ public class HorizontalCellStyleStrategy extends AbstractVerticalCellStyleStrate
     @Override
     protected WriteCellStyle contentCellStyle(Cell cell, Head head, Integer relativeRowIndex) {
         if (CollectionUtils.isEmpty(contentWriteCellStyleList)) {
-            return null;
+            return new WriteCellStyle();
         }
         return contentWriteCellStyleList.get(relativeRowIndex % contentWriteCellStyleList.size());
     }

src/test/java/com/alibaba/easyexcel/test/core/annotation/AnnotationData.java

@@ -9,7 +9,6 @@ import com.alibaba.excel.annotation.format.NumberFormat;
 import com.alibaba.excel.annotation.write.style.ColumnWidth;
 import com.alibaba.excel.annotation.write.style.ContentRowHeight;
 import com.alibaba.excel.annotation.write.style.HeadRowHeight;
-import com.alibaba.excel.converters.doubleconverter.DoubleStringConverter;
 
 import lombok.Data;
 
@@ -24,7 +23,7 @@ public class AnnotationData {
     @ExcelProperty("日期")
     @DateTimeFormat("yyyy年MM月dd日HH时mm分ss秒")
     private Date date;
-    @ExcelProperty(value = "数字", converter = DoubleStringConverter.class)
+    @ExcelProperty(value = "数字")
     @NumberFormat("#.##%")
     private Double number;
     @ExcelIgnore

src/test/java/com/alibaba/easyexcel/test/core/celldata/CellDataData.java

@@ -17,5 +17,5 @@ public class CellDataData {
     private CellData<Date> date;
     private CellData<Integer> integer1;
     private Integer integer2;
-    private CellData formulaValue;
+    private CellData<?> formulaValue;
 }

src/test/java/com/alibaba/easyexcel/test/core/celldata/CellDataDataTest.java

@@ -55,7 +55,7 @@ public class CellDataDataTest {
     private List<CellDataData> data() throws Exception {
         List<CellDataData> list = new ArrayList<CellDataData>();
         CellDataData cellDataData = new CellDataData();
-        cellDataData.setDate(new CellData<Date>(DateUtils.parseDate("2020-01-01 01:01:01")));
+        cellDataData.setDate(new CellData<>(DateUtils.parseDate("2020-01-01 01:01:01")));
         CellData<Integer> integer1 = new CellData<Integer>();
         integer1.setType(CellDataTypeEnum.NUMBER);
         integer1.setNumberValue(BigDecimal.valueOf(2L));

src/test/java/com/alibaba/easyexcel/test/core/converter/ConverterData.java

@@ -34,5 +34,5 @@ public class ConverterData {
     @ExcelProperty("字符串")
     private String string;
     @ExcelProperty("自定义")
-    private CellData cellData;
+    private CellData<?> cellData;
 }

src/test/java/com/alibaba/easyexcel/test/core/nomodel/NoModelDataTest.java

@@ -7,6 +7,7 @@ import java.util.Map;
 
 import com.alibaba.easyexcel.test.util.TestFileUtil;
 import com.alibaba.excel.EasyExcel;
+import com.alibaba.excel.util.DateUtils;
 
 import org.junit.Assert;
 import org.junit.BeforeClass;
@@ -34,35 +35,40 @@ public class NoModelDataTest {
     }
 
     @Test
-    public void t01ReadAndWrite07() {
+    public void t01ReadAndWrite07() throws Exception {
         readAndWrite(file07, fileRepeat07);
     }
 
     @Test
-    public void t02ReadAndWrite03() {
+    public void t02ReadAndWrite03() throws Exception {
         readAndWrite(file03, fileRepeat03);
     }
 
-    private void readAndWrite(File file, File fileRepeat) {
+    private void readAndWrite(File file, File fileRepeat) throws Exception {
         EasyExcel.write(file).sheet().doWrite(data());
         List<Map<Integer, String>> result = EasyExcel.read(file).headRowNumber(0).sheet().doReadSync();
         Assert.assertEquals(10, result.size());
         Map<Integer, String> data10 = result.get(9);
         Assert.assertEquals("string19", data10.get(0));
+        Assert.assertEquals("109", data10.get(1));
+        Assert.assertEquals("2020-01-01 01:01:01", data10.get(2));
+
         EasyExcel.write(fileRepeat).sheet().doWrite(result);
         result = EasyExcel.read(fileRepeat).headRowNumber(0).sheet().doReadSync();
         Assert.assertEquals(10, result.size());
         data10 = result.get(9);
         Assert.assertEquals("string19", data10.get(0));
+        Assert.assertEquals("109", data10.get(1));
+        Assert.assertEquals("2020-01-01 01:01:01", data10.get(2));
     }
 
-    private List<List<String>> data() {
+    private List<List<Object>> data() throws Exception {
-        List<List<String>> list = new ArrayList<>();
+        List<List<Object>> list = new ArrayList<>();
         for (int i = 0; i < 10; i++) {
-            List<String> data = new ArrayList<>();
+            List<Object> data = new ArrayList<>();
             data.add("string1" + i);
-            data.add("string2" + i);
+            data.add(100 + i);
-            data.add("string3" + i);
+            data.add(DateUtils.parseDate("2020-01-01 01:01:01"));
             list.add(data);
         }
         return list;

src/test/java/com/alibaba/easyexcel/test/demo/fill/FillTest.java

@@ -2,6 +2,7 @@ package com.alibaba.easyexcel.test.demo.fill;
 
 import java.io.File;
 import java.util.ArrayList;
+import java.util.Date;
 import java.util.HashMap;
 import java.util.List;
 import java.util.Map;
@@ -205,7 +206,9 @@ public class FillTest {
         excelWriter.fill(new FillWrapper("data3", data()), writeSheet);
 
         Map<String, Object> map = new HashMap<String, Object>();
-        map.put("date", "2019年10月9日13:28:28");
+        //map.put("date", "2019年10月9日13:28:28");
+        map.put("date", new Date());
+
         excelWriter.fill(map, writeSheet);
 
         // 别忘记关闭流

src/test/java/com/alibaba/easyexcel/test/temp/poi/TestCell.java

@@ -13,6 +13,6 @@ import lombok.Data;
  **/
 @Data
 public class TestCell {
-    private CellData c1;
+    private CellData<?> c1;
     private CellData<List<String>> c2;
 }