diff --git a/src/main/java/com/alibaba/excel/constant/BuiltinFormats.java b/src/main/java/com/alibaba/excel/constant/BuiltinFormats.java
index b742cb6c..ec7d5c9a 100644
--- a/src/main/java/com/alibaba/excel/constant/BuiltinFormats.java
+++ b/src/main/java/com/alibaba/excel/constant/BuiltinFormats.java
@@ -1,6 +1,9 @@
 package com.alibaba.excel.constant;
 
 import java.util.Locale;
+import java.util.Map;
+
+import com.alibaba.excel.util.MapUtils;
 
 /**
  * Excel's built-in format conversion.Currently only supports Chinese.
@@ -363,6 +366,10 @@ public class BuiltinFormats {
         // end
     };
 
+    public static final Map<String, Short> BUILTIN_FORMATS_MAP_CN = buildMap(BUILTIN_FORMATS_CN);
+    public static final Map<String, Short> BUILTIN_FORMATS_MAP_US = buildMap(BUILTIN_FORMATS_US);
+    public static final short MIN_CUSTOM_DATA_FORMAT_INDEX = 82;
+
     public static String getBuiltinFormat(Short index, String defaultFormat, Locale locale) {
         String[] builtinFormat = switchBuiltinFormats(locale);
         if (index == null || index < 0 || index >= builtinFormat.length) {
@@ -371,11 +378,26 @@ public class BuiltinFormats {
         return builtinFormat[index];
     }
 
-    private static String[] switchBuiltinFormats(Locale locale) {
+    public static String[] switchBuiltinFormats(Locale locale) {
         if (locale != null && Locale.US.getCountry().equals(locale.getCountry())) {
             return BUILTIN_FORMATS_US;
         }
         return BUILTIN_FORMATS_CN;
     }
 
+    public static Map<String, Short> switchBuiltinFormatsMap(Locale locale) {
+        if (locale != null && Locale.US.getCountry().equals(locale.getCountry())) {
+            return BUILTIN_FORMATS_MAP_US;
+        }
+        return BUILTIN_FORMATS_MAP_CN;
+    }
+
+    private static Map<String, Short> buildMap(String[] builtinFormats) {
+        Map<String, Short> map = MapUtils.newHashMapWithExpectedSize(builtinFormats.length);
+        for (int i = 0; i < builtinFormats.length; i++) {
+            map.put(builtinFormats[i], (short)i);
+        }
+        return map;
+    }
+
 }
diff --git a/src/main/java/com/alibaba/excel/csv/CsvCell.java b/src/main/java/com/alibaba/excel/csv/CsvCell.java
deleted file mode 100644
index 84808bf0..00000000
--- a/src/main/java/com/alibaba/excel/csv/CsvCell.java
+++ /dev/null
@@ -1,231 +0,0 @@
-package com.alibaba.excel.csv;
-
-import java.time.LocalDateTime;
-import java.util.Calendar;
-import java.util.Date;
-
-import org.apache.poi.ss.formula.FormulaParseException;
-import org.apache.poi.ss.usermodel.Cell;
-import org.apache.poi.ss.usermodel.CellStyle;
-import org.apache.poi.ss.usermodel.CellType;
-import org.apache.poi.ss.usermodel.Comment;
-import org.apache.poi.ss.usermodel.Hyperlink;
-import org.apache.poi.ss.usermodel.RichTextString;
-import org.apache.poi.ss.usermodel.Row;
-import org.apache.poi.ss.usermodel.Sheet;
-import org.apache.poi.ss.util.CellAddress;
-import org.apache.poi.ss.util.CellRangeAddress;
-
-/**
- * TODO
- *
- * @author Jiaju Zhuang
- */
-public class CsvCell implements Cell {
-
-    private String value;
-
-    @Override
-    public int getColumnIndex() {
-        return 0;
-    }
-
-    @Override
-    public int getRowIndex() {
-        return 0;
-    }
-
-    @Override
-    public Sheet getSheet() {
-        return null;
-    }
-
-    @Override
-    public Row getRow() {
-        return null;
-    }
-
-    @Override
-    public void setCellType(CellType cellType) {
-
-    }
-
-    @Override
-    public void setBlank() {
-
-    }
-
-    @Override
-    public CellType getCellType() {
-        return null;
-    }
-
-    @Override
-    public CellType getCellTypeEnum() {
-        return null;
-    }
-
-    @Override
-    public CellType getCachedFormulaResultType() {
-        return null;
-    }
-
-    @Override
-    public CellType getCachedFormulaResultTypeEnum() {
-        return null;
-    }
-
-    @Override
-    public void setCellValue(double value) {
-        this.value = value + "";
-    }
-
-    @Override
-    public void setCellValue(Date value) {
-        this.value = value.toString();
-
-    }
-
-    @Override
-    public void setCellValue(LocalDateTime value) {
-
-    }
-
-    @Override
-    public void setCellValue(Calendar value) {
-
-    }
-
-    @Override
-    public void setCellValue(RichTextString value) {
-
-    }
-
-    @Override
-    public void setCellValue(String value) {
-        this.value = value;
-    }
-
-    @Override
-    public void setCellFormula(String formula) throws FormulaParseException, IllegalStateException {
-
-    }
-
-    @Override
-    public void removeFormula() throws IllegalStateException {
-
-    }
-
-    @Override
-    public String getCellFormula() {
-        return null;
-    }
-
-    @Override
-    public double getNumericCellValue() {
-        return 0;
-    }
-
-    @Override
-    public Date getDateCellValue() {
-        return null;
-    }
-
-    @Override
-    public LocalDateTime getLocalDateTimeCellValue() {
-        return null;
-    }
-
-    @Override
-    public RichTextString getRichStringCellValue() {
-        return null;
-    }
-
-    @Override
-    public String getStringCellValue() {
-        return value;
-    }
-
-    @Override
-    public void setCellValue(boolean value) {
-
-    }
-
-    @Override
-    public void setCellErrorValue(byte value) {
-
-    }
-
-    @Override
-    public boolean getBooleanCellValue() {
-        return false;
-    }
-
-    @Override
-    public byte getErrorCellValue() {
-        return 0;
-    }
-
-    @Override
-    public void setCellStyle(CellStyle style) {
-
-    }
-
-    @Override
-    public CellStyle getCellStyle() {
-        return null;
-    }
-
-    @Override
-    public void setAsActiveCell() {
-
-    }
-
-    @Override
-    public CellAddress getAddress() {
-        return null;
-    }
-
-    @Override
-    public void setCellComment(Comment comment) {
-
-    }
-
-    @Override
-    public Comment getCellComment() {
-        return null;
-    }
-
-    @Override
-    public void removeCellComment() {
-
-    }
-
-    @Override
-    public Hyperlink getHyperlink() {
-        return null;
-    }
-
-    @Override
-    public void setHyperlink(Hyperlink link) {
-
-    }
-
-    @Override
-    public void removeHyperlink() {
-
-    }
-
-    @Override
-    public CellRangeAddress getArrayFormulaRange() {
-        return null;
-    }
-
-    @Override
-    public boolean isPartOfArrayFormulaGroup() {
-        return false;
-    }
-
-
-
-}
diff --git a/src/main/java/com/alibaba/excel/csv/CsvDataFormat.java b/src/main/java/com/alibaba/excel/csv/CsvDataFormat.java
deleted file mode 100644
index 2961fbf1..00000000
--- a/src/main/java/com/alibaba/excel/csv/CsvDataFormat.java
+++ /dev/null
@@ -1,15 +0,0 @@
-package com.alibaba.excel.csv;
-
-import org.apache.poi.ss.usermodel.DataFormat;
-
-public class CsvDataFormat implements DataFormat {
-    @Override
-    public short getFormat(String format) {
-        return 0;
-    }
-
-    @Override
-    public String getFormat(short index) {
-        return null;
-    }
-}
diff --git a/src/main/java/com/alibaba/excel/metadata/csv/CsvCell.java b/src/main/java/com/alibaba/excel/metadata/csv/CsvCell.java
new file mode 100644
index 00000000..ef627392
--- /dev/null
+++ b/src/main/java/com/alibaba/excel/metadata/csv/CsvCell.java
@@ -0,0 +1,291 @@
+package com.alibaba.excel.metadata.csv;
+
+import java.math.BigDecimal;
+import java.time.LocalDateTime;
+import java.time.ZoneId;
+import java.util.Calendar;
+import java.util.Date;
+
+import com.alibaba.excel.metadata.data.FormulaData;
+
+import org.apache.poi.ss.SpreadsheetVersion;
+import org.apache.poi.ss.usermodel.CellBase;
+import org.apache.poi.ss.usermodel.CellStyle;
+import org.apache.poi.ss.usermodel.CellType;
+import org.apache.poi.ss.usermodel.Comment;
+import org.apache.poi.ss.usermodel.Hyperlink;
+import org.apache.poi.ss.usermodel.RichTextString;
+import org.apache.poi.ss.usermodel.Row;
+import org.apache.poi.ss.usermodel.Sheet;
+import org.apache.poi.ss.util.CellRangeAddress;
+
+/**
+ * csv cell
+ *
+ * @author Jiaju Zhuang
+ */
+public class CsvCell extends CellBase {
+
+    /**
+     * column index
+     */
+    private Integer columnIndex;
+
+    /**
+     * cell type
+     */
+    private CellType cellType;
+    /**
+     * row
+     */
+    private final CsvRow csvRow;
+
+    /**
+     * {@link CellType#NUMERIC}
+     */
+    private BigDecimal numberValue;
+    /**
+     * {@link CellType#STRING} and {@link CellType#ERROR} {@link CellType#FORMULA}
+     */
+    private String stringValue;
+    /**
+     * {@link CellType#BOOLEAN}
+     */
+    private Boolean booleanValue;
+
+    /**
+     * {@link CellType#NUMERIC}
+     */
+    private LocalDateTime dateValue;
+
+    /**
+     * formula
+     */
+    private FormulaData formulaData;
+
+    /**
+     * rich text string
+     */
+    private RichTextString richTextString;
+
+    /**
+     * style
+     */
+    private CellStyle cellStyle;
+
+    public CsvCell(CsvRow csvRow, Integer columnIndex, CellType cellType) {
+        this.csvRow = csvRow;
+        this.columnIndex = columnIndex;
+        this.cellType = cellType;
+    }
+
+    @Override
+    protected void setCellTypeImpl(CellType cellType) {
+        this.cellType = cellType;
+    }
+
+    @Override
+    protected void setCellFormulaImpl(String formula) {
+        FormulaData formulaData = new FormulaData();
+        formulaData.setFormulaValue(formula);
+        this.formulaData = formulaData;
+    }
+
+    @Override
+    protected void removeFormulaImpl() {
+        this.formulaData = null;
+    }
+
+    @Override
+    protected void setCellValueImpl(double value) {
+        numberValue = BigDecimal.valueOf(value);
+    }
+
+    @Override
+    protected void setCellValueImpl(Date value) {
+        if (value == null) {
+            return;
+        }
+        this.dateValue = LocalDateTime.ofInstant(value.toInstant(), ZoneId.systemDefault());
+    }
+
+    @Override
+    protected void setCellValueImpl(LocalDateTime value) {
+        this.dateValue = value;
+    }
+
+    @Override
+    protected void setCellValueImpl(Calendar value) {
+        if (value == null) {
+            return;
+        }
+        this.dateValue = LocalDateTime.ofInstant(value.toInstant(), ZoneId.systemDefault());
+    }
+
+    @Override
+    protected void setCellValueImpl(String value) {
+        this.stringValue = value;
+    }
+
+    @Override
+    protected void setCellValueImpl(RichTextString value) {
+        richTextString = value;
+    }
+
+    @Override
+    protected SpreadsheetVersion getSpreadsheetVersion() {
+        return null;
+    }
+
+    @Override
+    public int getColumnIndex() {
+        return columnIndex;
+    }
+
+    @Override
+    public int getRowIndex() {
+        return csvRow.getRowNum();
+    }
+
+    @Override
+    public Sheet getSheet() {
+        return csvRow.getSheet();
+    }
+
+    @Override
+    public Row getRow() {
+        return csvRow;
+    }
+
+    @Override
+    public CellType getCellType() {
+        return cellType;
+    }
+
+    @Override
+    public CellType getCachedFormulaResultType() {
+        return getCellType();
+    }
+
+    @Override
+    public CellType getCachedFormulaResultTypeEnum() {
+        return getCellType();
+    }
+
+    @Override
+    public String getCellFormula() {
+        if (formulaData == null) {
+            return null;
+        }
+        return formulaData.getFormulaValue();
+    }
+
+    @Override
+    public double getNumericCellValue() {
+        if (numberValue == null) {
+            return 0;
+        }
+        return numberValue.doubleValue();
+    }
+
+    @Override
+    public Date getDateCellValue() {
+        if (dateValue == null) {
+            return null;
+        }
+        return Date.from(dateValue.atZone(ZoneId.systemDefault()).toInstant());
+    }
+
+    @Override
+    public LocalDateTime getLocalDateTimeCellValue() {
+        return dateValue;
+    }
+
+    @Override
+    public RichTextString getRichStringCellValue() {
+        return richTextString;
+    }
+
+    @Override
+    public String getStringCellValue() {
+        return stringValue;
+    }
+
+    @Override
+    public void setCellValue(boolean value) {
+        this.booleanValue = value;
+    }
+
+    @Override
+    public void setCellErrorValue(byte value) {
+        this.numberValue = BigDecimal.valueOf(value);
+    }
+
+    @Override
+    public boolean getBooleanCellValue() {
+        return booleanValue;
+    }
+
+    @Override
+    public byte getErrorCellValue() {
+        if (numberValue == null) {
+            return 0;
+        }
+        return numberValue.byteValue();
+    }
+
+    @Override
+    public void setCellStyle(CellStyle style) {
+        this.cellStyle = style;
+    }
+
+    @Override
+    public CellStyle getCellStyle() {
+        return cellStyle;
+    }
+
+    @Override
+    public void setAsActiveCell() {
+
+    }
+
+    @Override
+    public void setCellComment(Comment comment) {
+
+    }
+
+    @Override
+    public Comment getCellComment() {
+        return null;
+    }
+
+    @Override
+    public void removeCellComment() {
+
+    }
+
+    @Override
+    public Hyperlink getHyperlink() {
+        return null;
+    }
+
+    @Override
+    public void setHyperlink(Hyperlink link) {
+
+    }
+
+    @Override
+    public void removeHyperlink() {
+
+    }
+
+    @Override
+    public CellRangeAddress getArrayFormulaRange() {
+        return null;
+    }
+
+    @Override
+    public boolean isPartOfArrayFormulaGroup() {
+        return false;
+    }
+}
diff --git a/src/main/java/com/alibaba/excel/csv/CsvCellStyle.java b/src/main/java/com/alibaba/excel/metadata/csv/CsvCellStyle.java
similarity index 93%
rename from src/main/java/com/alibaba/excel/csv/CsvCellStyle.java
rename to src/main/java/com/alibaba/excel/metadata/csv/CsvCellStyle.java
index 318b42a4..8c8fe981 100644
--- a/src/main/java/com/alibaba/excel/csv/CsvCellStyle.java
+++ b/src/main/java/com/alibaba/excel/metadata/csv/CsvCellStyle.java
@@ -1,4 +1,6 @@
-package com.alibaba.excel.csv;
+package com.alibaba.excel.metadata.csv;
+
+import com.alibaba.excel.metadata.data.DataFormatData;
 
 import org.apache.poi.ss.usermodel.BorderStyle;
 import org.apache.poi.ss.usermodel.CellStyle;
@@ -9,11 +11,26 @@ import org.apache.poi.ss.usermodel.HorizontalAlignment;
 import org.apache.poi.ss.usermodel.VerticalAlignment;
 
 /**
- * TODO
+ * csv cell style
  *
  * @author Jiaju Zhuang
  */
 public class CsvCellStyle implements CellStyle {
+
+    /**
+     * data format
+     */
+    private DataFormatData dataFormatData;
+
+    /**
+     * index
+     */
+    private Short index;
+
+    public CsvCellStyle(Short index) {
+        this.index = index;
+    }
+
     @Override
     public short getIndex() {
         return 0;
diff --git a/src/main/java/com/alibaba/excel/metadata/csv/CsvDataFormat.java b/src/main/java/com/alibaba/excel/metadata/csv/CsvDataFormat.java
new file mode 100644
index 00000000..1dcc7c2e
--- /dev/null
+++ b/src/main/java/com/alibaba/excel/metadata/csv/CsvDataFormat.java
@@ -0,0 +1,65 @@
+package com.alibaba.excel.metadata.csv;
+
+import java.util.List;
+import java.util.Locale;
+import java.util.Map;
+
+import com.alibaba.excel.constant.BuiltinFormats;
+import com.alibaba.excel.util.ListUtils;
+import com.alibaba.excel.util.MapUtils;
+
+import org.apache.poi.ss.usermodel.DataFormat;
+
+/**
+ * format data
+ *
+ * @author Jiaju Zhuang
+ */
+public class CsvDataFormat implements DataFormat {
+    /**
+     * It is stored in both map and list for easy retrieval
+     */
+    private final Map<String, Short> formatMap;
+    private final List<String> formatList;
+
+    /**
+     * Excel's built-in format conversion.
+     */
+    private final Map<String, Short> builtinFormatsMap;
+    private final String[] builtinFormats;
+
+    public CsvDataFormat(Locale locale) {
+        formatMap = MapUtils.newHashMap();
+        formatList = ListUtils.newArrayList();
+        builtinFormatsMap = BuiltinFormats.switchBuiltinFormatsMap(locale);
+        builtinFormats = BuiltinFormats.switchBuiltinFormats(locale);
+    }
+
+    @Override
+    public short getFormat(String format) {
+        Short index = builtinFormatsMap.get(format);
+        if (index != null) {
+            return index;
+        }
+        index = formatMap.get(format);
+        if (index != null) {
+            return index;
+        }
+        formatList.add(format);
+        index = (short)formatList.size();
+        formatMap.put(format, index);
+        return index;
+    }
+
+    @Override
+    public String getFormat(short index) {
+        if (index < BuiltinFormats.MIN_CUSTOM_DATA_FORMAT_INDEX) {
+            return builtinFormats[index];
+        }
+        int actualIndex = index - BuiltinFormats.MIN_CUSTOM_DATA_FORMAT_INDEX;
+        if (actualIndex >= 0 && actualIndex < formatList.size()) {
+            return formatList.get(actualIndex);
+        }
+        return null;
+    }
+}
diff --git a/src/main/java/com/alibaba/excel/metadata/csv/CsvRichTextString.java b/src/main/java/com/alibaba/excel/metadata/csv/CsvRichTextString.java
new file mode 100644
index 00000000..1c54b0c3
--- /dev/null
+++ b/src/main/java/com/alibaba/excel/metadata/csv/CsvRichTextString.java
@@ -0,0 +1,68 @@
+package com.alibaba.excel.metadata.csv;
+
+import org.apache.poi.ss.usermodel.Font;
+import org.apache.poi.ss.usermodel.RichTextString;
+
+/**
+ * rich text string
+ *
+ * @author Jiaju Zhuang
+ */
+public class CsvRichTextString implements RichTextString {
+    /**
+     * string
+     */
+    private final String string;
+
+    public CsvRichTextString(String string) {
+        this.string = string;
+    }
+
+    @Override
+    public void applyFont(int startIndex, int endIndex, short fontIndex) {
+
+    }
+
+    @Override
+    public void applyFont(int startIndex, int endIndex, Font font) {
+
+    }
+
+    @Override
+    public void applyFont(Font font) {
+
+    }
+
+    @Override
+    public void clearFormatting() {
+
+    }
+
+    @Override
+    public String getString() {
+        return string;
+    }
+
+    @Override
+    public int length() {
+        if (string == null) {
+            return 0;
+        }
+        return string.length();
+    }
+
+    @Override
+    public int numFormattingRuns() {
+        return 0;
+    }
+
+    @Override
+    public int getIndexOfFormattingRun(int index) {
+        return 0;
+    }
+
+    @Override
+    public void applyFont(short fontIndex) {
+
+    }
+}
diff --git a/src/main/java/com/alibaba/excel/csv/CsvRow.java b/src/main/java/com/alibaba/excel/metadata/csv/CsvRow.java
similarity index 59%
rename from src/main/java/com/alibaba/excel/csv/CsvRow.java
rename to src/main/java/com/alibaba/excel/metadata/csv/CsvRow.java
index 16129263..d7248313 100644
--- a/src/main/java/com/alibaba/excel/csv/CsvRow.java
+++ b/src/main/java/com/alibaba/excel/metadata/csv/CsvRow.java
@@ -1,9 +1,10 @@
-package com.alibaba.excel.csv;
+package com.alibaba.excel.metadata.csv;
 
-import java.util.ArrayList;
 import java.util.Iterator;
 import java.util.List;
 
+import org.apache.commons.collections4.CollectionUtils;
+import org.apache.commons.compress.utils.Lists;
 import org.apache.poi.ss.usermodel.Cell;
 import org.apache.poi.ss.usermodel.CellStyle;
 import org.apache.poi.ss.usermodel.CellType;
@@ -11,64 +12,98 @@ import org.apache.poi.ss.usermodel.Row;
 import org.apache.poi.ss.usermodel.Sheet;
 
 /**
- * TODO
+ * csv row
  *
  * @author Jiaju Zhuang
  */
 public class CsvRow implements Row {
 
-   public List<CsvCell> list = new ArrayList<>();
+    /**
+     * cell list
+     */
+    private final List<CsvCell> cellList;
+
+    /**
+     * sheet
+     */
+    private final CsvSheet csvSheet;
+    /**
+     * row index
+     */
+    private Integer rowIndex;
+
+    /**
+     * style
+     */
+    private CellStyle cellStyle;
+
+    public CsvRow(CsvSheet csvSheet, Integer rowIndex) {
+        cellList = Lists.newArrayList();
+        this.csvSheet = csvSheet;
+        this.rowIndex = rowIndex;
+    }
 
     @Override
     public Cell createCell(int column) {
-        CsvCell cell = new CsvCell();
-        list.add(cell);
+        CsvCell cell = new CsvCell(this, column, null);
+        cellList.add(cell);
         return cell;
     }
 
     @Override
     public Cell createCell(int column, CellType type) {
-        return null;
+        CsvCell cell = new CsvCell(this, column, type);
+        cellList.add(cell);
+        return cell;
     }
 
     @Override
     public void removeCell(Cell cell) {
-
+        cellList.remove(cell);
     }
 
     @Override
     public void setRowNum(int rowNum) {
-
+        this.rowIndex = rowNum;
     }
 
     @Override
     public int getRowNum() {
-        return 0;
+        return rowIndex;
     }
 
     @Override
     public Cell getCell(int cellnum) {
-        return list.get(cellnum);
+        if (cellnum >= cellList.size()) {
+            return null;
+        }
+        return cellList.get(cellnum - 1);
     }
 
     @Override
     public Cell getCell(int cellnum, MissingCellPolicy policy) {
-        return null;
+        return getCell(cellnum);
     }
 
     @Override
     public short getFirstCellNum() {
+        if (CollectionUtils.isEmpty(cellList)) {
+            return -1;
+        }
         return 0;
     }
 
     @Override
     public short getLastCellNum() {
-        return (short)list.size();
+        if (CollectionUtils.isEmpty(cellList)) {
+            return -1;
+        }
+        return (short)cellList.size();
     }
 
     @Override
     public int getPhysicalNumberOfCells() {
-        return 0;
+        return getRowNum();
     }
 
     @Override
@@ -108,22 +143,22 @@ public class CsvRow implements Row {
 
     @Override
     public CellStyle getRowStyle() {
-        return null;
+        return cellStyle;
     }
 
     @Override
     public void setRowStyle(CellStyle style) {
-
+        this.cellStyle = style;
     }
 
     @Override
     public Iterator<Cell> cellIterator() {
-        return null;
+        return (Iterator<Cell>)(Iterator<? extends Cell>)cellList.iterator();
     }
 
     @Override
     public Sheet getSheet() {
-        return null;
+        return csvSheet;
     }
 
     @Override
@@ -143,6 +178,6 @@ public class CsvRow implements Row {
 
     @Override
     public Iterator<Cell> iterator() {
-        return null;
+        return cellIterator();
     }
 }
diff --git a/src/main/java/com/alibaba/excel/csv/CsvSheet.java b/src/main/java/com/alibaba/excel/metadata/csv/CsvSheet.java
similarity index 77%
rename from src/main/java/com/alibaba/excel/csv/CsvSheet.java
rename to src/main/java/com/alibaba/excel/metadata/csv/CsvSheet.java
index db21787b..07f09e73 100644
--- a/src/main/java/com/alibaba/excel/csv/CsvSheet.java
+++ b/src/main/java/com/alibaba/excel/metadata/csv/CsvSheet.java
@@ -1,6 +1,9 @@
-package com.alibaba.excel.csv;
+package com.alibaba.excel.metadata.csv;
 
+import java.io.Closeable;
 import java.io.File;
+import java.io.FileNotFoundException;
+import java.io.FileOutputStream;
 import java.io.IOException;
 import java.io.OutputStream;
 import java.io.OutputStreamWriter;
@@ -9,10 +12,11 @@ import java.util.Collection;
 import java.util.Iterator;
 import java.util.List;
 import java.util.Map;
-import java.util.stream.Collectors;
 
+import com.alibaba.excel.exception.ExcelGenerateException;
 import com.alibaba.excel.util.ListUtils;
 
+import lombok.Data;
 import org.apache.commons.csv.CSVFormat;
 import org.apache.commons.csv.CSVPrinter;
 import org.apache.poi.ss.usermodel.AutoFilter;
@@ -36,62 +40,122 @@ import org.apache.poi.ss.util.CellRangeAddress;
 import org.apache.poi.ss.util.PaneInformation;
 
 /**
- * TODO
+ * csv sheet
  *
  * @author Jiaju Zhuang
  */
-public class CsvSheet implements Sheet {
-
-    public static int rowCacheCount = 500;
-    public static Charset defaultCharset = Charset.defaultCharset();
-
-    public CSVPrinter csvPrinter;
-
-    private int lastRowNum = -1;
-
-    private List<CsvRow> rowCache = ListUtils.newArrayListWithExpectedSize(rowCacheCount);
-
-    public CsvSheet(File file) throws IOException {
-        csvPrinter = CSVFormat.DEFAULT.print(file, defaultCharset);
-    }
-
-    public CsvSheet(OutputStream outputStream) throws IOException {
-        csvPrinter = CSVFormat.DEFAULT.print(new OutputStreamWriter(outputStream));
+@Data
+public class CsvSheet implements Sheet, Closeable {
+
+    /**
+     * workbook
+     */
+    private CsvWorkbook csvWorkbook;
+    /**
+     * output
+     */
+    private Appendable out;
+    /**
+     * row cache
+     */
+    private Integer rowCacheCount;
+    /**
+     * format
+     */
+    public CSVFormat csvFormat;
+
+    /**
+     * last row index
+     */
+    private int lastRowIndex;
+    /**
+     * row cache
+     */
+    private List<CsvRow> rowCache;
+    /**
+     * csv printer
+     */
+    private CSVPrinter csvPrinter;
+
+    public CsvSheet(CsvWorkbook csvWorkbook, File file, Charset charset) throws FileNotFoundException {
+        this.csvWorkbook = csvWorkbook;
+        this.out = new OutputStreamWriter(new FileOutputStream(file), charset);
+        this.rowCacheCount = 500;
+        this.csvFormat = CSVFormat.DEFAULT;
+        this.lastRowIndex = -1;
+    }
+
+    public CsvSheet(CsvWorkbook csvWorkbook, OutputStream outputStream) {
+        this.csvWorkbook = csvWorkbook;
+        this.out = new OutputStreamWriter(outputStream);
+        this.rowCacheCount = 500;
+        this.csvFormat = CSVFormat.DEFAULT;
+        this.lastRowIndex = -1;
+    }
+
+    public CsvSheet(CsvWorkbook csvWorkbook, Appendable out) {
+        this.csvWorkbook = csvWorkbook;
+        this.out = out;
+        this.rowCacheCount = 500;
+        this.csvFormat = CSVFormat.DEFAULT;
+        this.lastRowIndex = -1;
     }
 
     @Override
     public Row createRow(int rownum) {
-        lastRowNum++;
-        assert rownum == lastRowNum : "csv create row must be in order.";
+        // Initialize the data when the row is first created
+        initSheet();
+
+        lastRowIndex++;
+        assert rownum == lastRowIndex : "csv create row must be in order.";
         printData();
-        CsvRow csvRow = new CsvRow();
+        CsvRow csvRow = new CsvRow(this, rownum);
         rowCache.add(csvRow);
         return csvRow;
     }
 
+    private void initSheet() {
+        if (csvPrinter != null) {
+            return;
+        }
+        rowCache = ListUtils.newArrayListWithExpectedSize(rowCacheCount);
+        try {
+            csvPrinter = csvFormat.print(out);
+        } catch (IOException e) {
+            throw new ExcelGenerateException(e);
+        }
+    }
+
     @Override
     public void removeRow(Row row) {
-
+        throw new UnsupportedOperationException("csv cannot move row.");
     }
 
     @Override
     public Row getRow(int rownum) {
-        return null;
+        int actualRowIndex = rownum - (lastRowIndex - rowCache.size()) - 1;
+        if (actualRowIndex < 0 || actualRowIndex > rowCache.size() - 1) {
+            throw new UnsupportedOperationException("The current data does not exist or has been flushed to disk\n.");
+        }
+        return rowCache.get(actualRowIndex);
     }
 
     @Override
     public int getPhysicalNumberOfRows() {
-        return 0;
+        return lastRowIndex - rowCache.size();
     }
 
     @Override
     public int getFirstRowNum() {
+        if (lastRowIndex < 0) {
+            return -1;
+        }
         return 0;
     }
 
     @Override
     public int getLastRowNum() {
-        return 0;
+        return lastRowIndex;
     }
 
     @Override
@@ -226,7 +290,7 @@ public class CsvSheet implements Sheet {
 
     @Override
     public Iterator<Row> rowIterator() {
-        return null;
+        return (Iterator<Row>)(Iterator<? extends Row>)rowCache.iterator();
     }
 
     @Override
@@ -556,7 +620,7 @@ public class CsvSheet implements Sheet {
 
     @Override
     public Workbook getWorkbook() {
-        return null;
+        return csvWorkbook;
     }
 
     @Override
@@ -657,23 +721,39 @@ public class CsvSheet implements Sheet {
 
     @Override
     public Iterator<Row> iterator() {
-        return null;
+        return rowIterator();
+    }
+
+    @Override
+    public void close() throws IOException {
+        // Avoid empty sheets
+        initSheet();
+
+        flushData();
+        csvPrinter.flush();
+        csvPrinter.close();
     }
 
     public void printData() {
         if (rowCache.size() >= rowCacheCount) {
             flushData();
-            rowCache.clear();
         }
     }
 
     public void flushData() {
         try {
             for (CsvRow row : rowCache) {
-                csvPrinter.printRecord(row.list.stream().map(CsvCell::getStringCellValue).collect(Collectors.toList()));
+                Iterator<Cell> cellIterator = row.cellIterator();
+                while (cellIterator.hasNext()) {
+                    CsvCell csvCell = (CsvCell)cellIterator.next();
+                    csvPrinter.print(csvCell.getStringCellValue());
+                }
+                csvPrinter.println();
             }
+            rowCache.clear();
         } catch (IOException e) {
-            e.printStackTrace();
+            throw new ExcelGenerateException(e);
         }
     }
+
 }
diff --git a/src/main/java/com/alibaba/excel/csv/CsvWorkbook.java b/src/main/java/com/alibaba/excel/metadata/csv/CsvWorkbook.java
similarity index 80%
rename from src/main/java/com/alibaba/excel/csv/CsvWorkbook.java
rename to src/main/java/com/alibaba/excel/metadata/csv/CsvWorkbook.java
index 082e770d..ae8a3e50 100644
--- a/src/main/java/com/alibaba/excel/csv/CsvWorkbook.java
+++ b/src/main/java/com/alibaba/excel/metadata/csv/CsvWorkbook.java
@@ -1,13 +1,13 @@
-package com.alibaba.excel.csv;
+package com.alibaba.excel.metadata.csv;
 
-import java.io.File;
 import java.io.IOException;
-import java.io.InputStream;
 import java.io.OutputStream;
 import java.util.Iterator;
 import java.util.List;
+import java.util.Locale;
 
 import lombok.Data;
+import org.apache.commons.compress.utils.Lists;
 import org.apache.poi.ss.SpreadsheetVersion;
 import org.apache.poi.ss.formula.udf.UDFFinder;
 import org.apache.poi.ss.usermodel.CellStyle;
@@ -22,21 +22,37 @@ import org.apache.poi.ss.usermodel.SheetVisibility;
 import org.apache.poi.ss.usermodel.Workbook;
 
 /**
- * TODO
+ * csv workbook
  *
  * @author Jiaju Zhuang
  */
 @Data
 public class CsvWorkbook implements Workbook {
-
+    /**
+     * output
+     */
+    private Appendable out;
+    /**
+     * locale
+     */
+    private Locale locale;
+
+    /**
+     * data format
+     */
+    private CsvDataFormat csvDataFormat;
+    /**
+     * sheet
+     */
     private CsvSheet csvSheet;
+    /**
+     * cell style
+     */
+    private List<CsvCellStyle> csvCellStyleList;
 
-    public CsvWorkbook(InputStream inputStream, File file) {
-        try {
-            this.csvSheet = new CsvSheet(file);
-        } catch (IOException e) {
-            e.printStackTrace();
-        }
+    public CsvWorkbook(Appendable out, Locale locale) {
+        this.out = out;
+        this.locale = locale;
     }
 
     @Override
@@ -91,11 +107,15 @@ public class CsvWorkbook implements Workbook {
 
     @Override
     public Sheet createSheet() {
+        assert csvSheet == null : "CSV repeat creation is not allowed.";
+        csvSheet = new CsvSheet(this, out);
         return csvSheet;
     }
 
     @Override
     public Sheet createSheet(String sheetname) {
+        assert csvSheet == null : "CSV repeat creation is not allowed.";
+        csvSheet = new CsvSheet(this, out);
         return csvSheet;
     }
 
@@ -116,12 +136,13 @@ public class CsvWorkbook implements Workbook {
 
     @Override
     public Sheet getSheetAt(int index) {
-        return null;
+        assert index == 0 : "CSV exists only in one sheet.";
+        return csvSheet;
     }
 
     @Override
     public Sheet getSheet(String name) {
-        return null;
+        return csvSheet;
     }
 
     @Override
@@ -162,24 +183,30 @@ public class CsvWorkbook implements Workbook {
 
     @Override
     public CellStyle createCellStyle() {
-        return new CsvCellStyle();
+        if (csvCellStyleList == null) {
+            csvCellStyleList = Lists.newArrayList();
+        }
+        CsvCellStyle csvCellStyle = new CsvCellStyle((short)csvCellStyleList.size());
+        csvCellStyleList.add(csvCellStyle);
+        return csvCellStyle;
     }
 
     @Override
     public int getNumCellStyles() {
-        return 0;
+        return csvCellStyleList.size();
     }
 
     @Override
     public CellStyle getCellStyleAt(int idx) {
-        return null;
+        if (idx < 0 || idx >= csvCellStyleList.size()) {
+            return null;
+        }
+        return csvCellStyleList.get(idx);
     }
 
     @Override
     public void write(OutputStream stream) throws IOException {
-        csvSheet.flushData();
-        csvSheet.csvPrinter.flush();
-        csvSheet.csvPrinter.close();
+        csvSheet.close();
     }
 
     @Override
@@ -274,7 +301,11 @@ public class CsvWorkbook implements Workbook {
 
     @Override
     public DataFormat createDataFormat() {
-        return new CsvDataFormat();
+        if (csvDataFormat != null) {
+            return csvDataFormat;
+        }
+        csvDataFormat = new CsvDataFormat(locale);
+        return csvDataFormat;
     }
 
     @Override
diff --git a/src/main/java/com/alibaba/excel/util/WorkBookUtil.java b/src/main/java/com/alibaba/excel/util/WorkBookUtil.java
index 0760e895..3fb6575e 100644
--- a/src/main/java/com/alibaba/excel/util/WorkBookUtil.java
+++ b/src/main/java/com/alibaba/excel/util/WorkBookUtil.java
@@ -1,8 +1,10 @@
 package com.alibaba.excel.util;
 
+import java.io.FileOutputStream;
 import java.io.IOException;
+import java.io.OutputStreamWriter;
 
-import com.alibaba.excel.csv.CsvWorkbook;
+import com.alibaba.excel.metadata.csv.CsvWorkbook;
 import com.alibaba.excel.metadata.data.DataFormatData;
 import com.alibaba.excel.metadata.data.WriteCellData;
 import com.alibaba.excel.write.metadata.holder.WriteWorkbookHolder;
@@ -67,12 +69,15 @@ public class WorkBookUtil {
                 return;
             case CSV:
                 CsvWorkbook csvWorkbook;
-                if (writeWorkbookHolder.getTempTemplateInputStream() != null) {
-                    csvWorkbook = new CsvWorkbook(writeWorkbookHolder.getTempTemplateInputStream(),
-                        writeWorkbookHolder.getFile());
+                if (writeWorkbookHolder.getFile() != null) {
+                    csvWorkbook = new CsvWorkbook(
+                        new OutputStreamWriter(new FileOutputStream(writeWorkbookHolder.getFile()),
+                            writeWorkbookHolder.getFileCharset()),
+                        writeWorkbookHolder.getGlobalConfiguration().getLocale());
                 } else {
-                    csvWorkbook = new CsvWorkbook(null, writeWorkbookHolder.getFile());
+                    csvWorkbook = new CsvWorkbook(null, writeWorkbookHolder.getGlobalConfiguration().getLocale());
                 }
+                CsvWorkbook csvWorkbook = new CsvWorkbook(writeWorkbookHolder);
                 writeWorkbookHolder.setCachedWorkbook(csvWorkbook);
                 writeWorkbookHolder.setWorkbook(csvWorkbook);
                 return;
diff --git a/src/main/java/com/alibaba/excel/write/metadata/holder/WriteWorkbookHolder.java b/src/main/java/com/alibaba/excel/write/metadata/holder/WriteWorkbookHolder.java
index a2a0d113..cb29ec22 100644
--- a/src/main/java/com/alibaba/excel/write/metadata/holder/WriteWorkbookHolder.java
+++ b/src/main/java/com/alibaba/excel/write/metadata/holder/WriteWorkbookHolder.java
@@ -7,6 +7,7 @@ import java.io.FileOutputStream;
 import java.io.IOException;
 import java.io.InputStream;
 import java.io.OutputStream;
+import java.nio.charset.Charset;
 import java.util.HashMap;
 import java.util.Map;
 
@@ -64,6 +65,10 @@ public class WriteWorkbookHolder extends AbstractWriteHolder {
      * If 'outputStream' and 'file' all not empty,file first
      */
     private File file;
+    /**
+     * charset of final output file
+     */
+    private Charset fileCharset;
     /**
      * Final output stream
      */
@@ -152,11 +157,6 @@ public class WriteWorkbookHolder extends AbstractWriteHolder {
         } else {
             this.autoCloseStream = writeWorkbook.getAutoCloseStream();
         }
-        try {
-            copyTemplate();
-        } catch (IOException e) {
-            throw new ExcelGenerateException("Copy template failure.", e);
-        }
         if (writeWorkbook.getExcelType() == null) {
             boolean isXls = (file != null && file.getName().endsWith(ExcelTypeEnum.XLS.getValue()))
                 || (writeWorkbook.getTemplateFile() != null
@@ -176,6 +176,11 @@ public class WriteWorkbookHolder extends AbstractWriteHolder {
         } else {
             this.excelType = writeWorkbook.getExcelType();
         }
+        try {
+            copyTemplate();
+        } catch (IOException e) {
+            throw new ExcelGenerateException("Copy template failure.", e);
+        }
         if (writeWorkbook.getMandatoryUseInputStream() == null) {
             this.mandatoryUseInputStream = Boolean.FALSE;
         } else {
@@ -203,6 +208,9 @@ public class WriteWorkbookHolder extends AbstractWriteHolder {
         if (writeWorkbook.getTemplateFile() == null && writeWorkbook.getTemplateInputStream() == null) {
             return;
         }
+        if (this.excelType == ExcelTypeEnum.CSV) {
+            throw new ExcelGenerateException("csv cannot use template.");
+        }
         byte[] templateFileByte = null;
         if (writeWorkbook.getTemplateFile() != null) {
             templateFileByte = FileUtils.readFileToByteArray(writeWorkbook.getTemplateFile());
diff --git a/src/test/java/com/alibaba/easyexcel/test/core/annotation/AnnotationDataTest.java b/src/test/java/com/alibaba/easyexcel/test/core/annotation/AnnotationDataTest.java
index 4489f1c1..54fa2700 100644
--- a/src/test/java/com/alibaba/easyexcel/test/core/annotation/AnnotationDataTest.java
+++ b/src/test/java/com/alibaba/easyexcel/test/core/annotation/AnnotationDataTest.java
@@ -4,26 +4,27 @@ import java.io.File;
 import java.util.ArrayList;
 import java.util.List;
 
-import org.junit.BeforeClass;
-import org.junit.Test;
-
 import com.alibaba.easyexcel.test.util.TestFileUtil;
 import com.alibaba.excel.EasyExcel;
 import com.alibaba.excel.util.DateUtils;
 
+import org.junit.BeforeClass;
+import org.junit.Test;
+
 /**
- *
  * @author Jiaju Zhuang
  */
 public class AnnotationDataTest {
 
     private static File file07;
     private static File file03;
+    private static File fileCsv;
 
     @BeforeClass
     public static void init() {
         file07 = TestFileUtil.createNewFile("annotation07.xlsx");
         file03 = TestFileUtil.createNewFile("annotation03.xls");
+        fileCsv = TestFileUtil.createNewFile("annotation.csv");
     }
 
     @Test
@@ -36,6 +37,11 @@ public class AnnotationDataTest {
         readAndWrite(file03);
     }
 
+    @Test
+    public void t02ReadAndWriteCsv() throws Exception {
+        readAndWrite(fileCsv);
+    }
+
     private void readAndWrite(File file) throws Exception {
         EasyExcel.write().file(file).head(AnnotationData.class).sheet().doWrite(data());
         EasyExcel.read().file(file).head(AnnotationData.class).registerReadListener(new AnnotationDataListener())
@@ -43,7 +49,7 @@ public class AnnotationDataTest {
     }
 
     private List<AnnotationData> data() throws Exception {
-        List<AnnotationData> list = new ArrayList<AnnotationData>();
+        List<AnnotationData> list = new ArrayList<>();
         AnnotationData data = new AnnotationData();
         data.setDate(DateUtils.parseDate("2020-01-01 01:01:01"));
         data.setNumber(99.99);