modify the class name to correct word

easyexcel-core/src/main/java/com/alibaba/excel/util/CellUtils.java

@@ -0,0 +1,36 @@
+package com.alibaba.excel.util;
+
+import org.apache.poi.ss.usermodel.Cell;
+
+/**
+ * @author gxz gongxuanzhang@foxmail.com
+ **/
+public class CellUtils {
+
+    private CellUtils() {
+        throw new UnsupportedOperationException("utils class can't invoke construction");
+    }
+
+    /**
+     * get cell value;
+     *
+     * @return maybe null when cell style is not in
+     **/
+    public static Object getCellValue(Cell cell) {
+        if (cell == null) {
+            throw new NullPointerException("cell must be not null");
+        }
+        switch (cell.getCellType()) {
+            case NUMERIC:
+                return cell.getNumericCellValue();
+            case STRING:
+                return cell.getStringCellValue();
+            case BOOLEAN:
+                return cell.getBooleanCellValue();
+            default:
+                return null;
+        }
+    }
+
+
+}

easyexcel-core/src/main/java/com/alibaba/excel/write/merge/LoopMergeStrategy.java

@@ -1,9 +1,15 @@
 package com.alibaba.excel.write.merge;
 
 import com.alibaba.excel.metadata.property.LoopMergeProperty;
+import com.alibaba.excel.util.CellUtils;
 import com.alibaba.excel.write.handler.RowWriteHandler;
+import com.alibaba.excel.write.handler.WorkbookWriteHandler;
 import com.alibaba.excel.write.handler.context.RowWriteHandlerContext;
-
+import com.alibaba.excel.write.handler.context.WorkbookWriteHandlerContext;
+import com.alibaba.excel.write.metadata.holder.WriteSheetHolder;
+import org.apache.poi.ss.usermodel.Cell;
+import org.apache.poi.ss.usermodel.Row;
+import org.apache.poi.ss.usermodel.Sheet;
 import org.apache.poi.ss.util.CellRangeAddress;
 
 /**
@@ -11,7 +17,7 @@ import org.apache.poi.ss.util.CellRangeAddress;
  *
  * @author Jiaju Zhuang
  */
-public class LoopMergeStrategy implements RowWriteHandler {
+public class LoopMergeStrategy implements RowWriteHandler, WorkbookWriteHandler {
     /**
      * Each row
      */
@@ -25,6 +31,22 @@ public class LoopMergeStrategy implements RowWriteHandler {
      */
     private final int columnIndex;
 
+    //  custom merge field
+
+    /**
+     * custom merge strategy
+     **/
+    private ValueSetting valueSetting;
+    /**
+     * current merged value cache.
+     **/
+    private Object[][] currentMergedValue;
+
+    /**
+     * support the last merged when excel row can't divisible by eachRow
+     **/
+    private int lastRowIndexStart;
+
     public LoopMergeStrategy(int eachRow, int columnIndex) {
         this(eachRow, 1, columnIndex);
     }
@@ -51,17 +73,89 @@ public class LoopMergeStrategy implements RowWriteHandler {
         this(loopMergeProperty.getEachRow(), loopMergeProperty.getColumnExtend(), columnIndex);
     }
 
+
+    /**
+     * setting you custom value when the cell merge.
+     * but if the data row can't divisible by eachRow.
+     * the last merge cell can't call the setting
+     *
+     * @param valueSetting setting value strategy
+     **/
+    public void setValueSetting(ValueSetting valueSetting) {
+        this.valueSetting = valueSetting;
+    }
+
+
     @Override
     public void afterRowDispose(RowWriteHandlerContext context) {
         if (context.getHead() || context.getRelativeRowIndex() == null) {
             return;
         }
+        if (this.valueSetting == null) {
+            doSimpleMerge(context);
+        } else {
+            doCustomMerge(context);
+        }
+    }
+
+    @Override
+    public void afterWorkbookDispose(WorkbookWriteHandlerContext context) {
+        if (this.currentMergedValue != null) {
+            WriteSheetHolder writeSheetHolder = context.getWriteContext().writeSheetHolder();
+            Sheet sheet = writeSheetHolder.getSheet();
+            CellRangeAddress cellRangeAddress = new CellRangeAddress(lastRowIndexStart,
+                lastRowIndexStart + eachRow - 1,
+                columnIndex, columnIndex + columnExtend - 1);
+            sheet.addMergedRegionUnsafe(cellRangeAddress);
+            this.currentMergedValue = null;
+        }
+    }
+
+
+    private void doCustomMerge(RowWriteHandlerContext context) {
+        int indexMod = context.getRelativeRowIndex() % eachRow;
+        if (indexMod == 0) {
+            this.currentMergedValue = new String[eachRow][columnExtend];
+            this.lastRowIndexStart = context.getRowIndex();
+        }
+        Row row = context.getRow();
+        for (int i = 0; i < columnExtend; i++) {
+            Cell cell = row.getCell(i + columnIndex);
+            Object cellValue = CellUtils.getCellValue(cell);
+            currentMergedValue[indexMod][i] = cellValue;
+        }
+        if (indexMod == eachRow - 1) {
+            CellRangeAddress cellRangeAddress = new CellRangeAddress(lastRowIndexStart,
+                lastRowIndexStart + eachRow - 1,
+                columnIndex, columnIndex + columnExtend - 1);
+            Sheet sheet = context.getWriteSheetHolder().getSheet();
+            sheet.addMergedRegionUnsafe(cellRangeAddress);
+            int mergedRowIndex = context.getRowIndex() - eachRow + 1;
+            Cell mergedCell = sheet.getRow(mergedRowIndex).getCell(columnIndex);
+            this.valueSetting.settingMergedCell(mergedCell, this.currentMergedValue);
+            this.currentMergedValue = null;
+        }
+    }
+
+    private void doSimpleMerge(RowWriteHandlerContext context) {
         if (context.getRelativeRowIndex() % eachRow == 0) {
             CellRangeAddress cellRangeAddress = new CellRangeAddress(context.getRowIndex(),
                 context.getRowIndex() + eachRow - 1,
                 columnIndex, columnIndex + columnExtend - 1);
-            context.getWriteSheetHolder().getSheet().addMergedRegionUnsafe(cellRangeAddress);
+            Sheet sheet = context.getWriteSheetHolder().getSheet();
+            sheet.addMergedRegionUnsafe(cellRangeAddress);
         }
     }
 
+    @FunctionalInterface
+    public interface ValueSetting {
+
+        /**
+         * setting merged cell value
+         *
+         * @param merged            merged cell
+         * @param beforeMergedValue the value of the cell to be merged
+         **/
+        void settingMergedCell(Cell merged, Object[][] beforeMergedValue);
+    }
 }

easyexcel-test/src/test/java/com/alibaba/easyexcel/test/demo/write/WriteTest.java

@@ -1,14 +1,5 @@
 package com.alibaba.easyexcel.test.demo.write;
 
-import java.io.File;
-import java.io.InputStream;
-import java.net.URL;
-import java.util.ArrayList;
-import java.util.Date;
-import java.util.HashSet;
-import java.util.List;
-import java.util.Set;
-
 import com.alibaba.easyexcel.test.util.TestFileUtil;
 import com.alibaba.excel.EasyExcel;
 import com.alibaba.excel.ExcelWriter;
@@ -39,7 +30,6 @@ import com.alibaba.excel.write.metadata.style.WriteCellStyle;
 import com.alibaba.excel.write.metadata.style.WriteFont;
 import com.alibaba.excel.write.style.HorizontalCellStyleStrategy;
 import com.alibaba.excel.write.style.column.LongestMatchColumnWidthStyleStrategy;
-
 import org.apache.poi.ss.usermodel.Cell;
 import org.apache.poi.ss.usermodel.CellStyle;
 import org.apache.poi.ss.usermodel.FillPatternType;
@@ -49,6 +39,15 @@ import org.apache.poi.xssf.streaming.SXSSFSheet;
 import org.junit.Ignore;
 import org.junit.Test;
 
+import java.io.File;
+import java.io.InputStream;
+import java.net.URL;
+import java.util.ArrayList;
+import java.util.Date;
+import java.util.HashSet;
+import java.util.List;
+import java.util.Set;
+
 /**
  * 写的常见写法
  *
@@ -563,6 +562,33 @@ public class WriteTest {
         EasyExcel.write(fileName, DemoData.class).registerWriteHandler(loopMergeStrategy).sheet("模板").doWrite(data());
     }
 
+    /**
+     * 自定义合并单元格
+     **/
+    @Test
+    public void customWrite() {
+        String fileName = TestFileUtil.getPath() + "mergeWrite" + System.currentTimeMillis() + ".xlsx";
+        //  每隔两行会合并 同mergeWrite的例子
+        LoopMergeStrategy loopMergeStrategy = new LoopMergeStrategy(2, 0);
+        //  这里设置合并之后单元格的值 此例子表示把单元格所有的字符串的值拼接起来 给合并之后的单元格.
+        //  mergedCell 是合并之后的单元格 我们可以直接进行操作，但是注意如果操作了这个单元格，如果再想拆分可能会和原数据不一样
+        //  values是一个二维数组  假如我们每两行合并一次，一次合并两列
+        //  那二维数组会把两行两列的数据提供给你
+        loopMergeStrategy.setValueSetting((mergedCell, values) -> {
+            StringBuilder mergedValue = new StringBuilder();
+            for (Object[] rowValues : values) {
+                for (Object cellValue : rowValues) {
+                    if (cellValue != null) {
+                        mergedValue.append(cellValue);
+                    }
+                }
+            }
+            mergedCell.setCellValue(mergedValue.toString());
+        });
+        // 这里 需要指定写用哪个class去写，然后写到第一个sheet，名字为模板 然后文件流会自动关闭
+        EasyExcel.write(fileName, DemoData.class).registerWriteHandler(loopMergeStrategy).sheet("模板").doWrite(data());
+    }
+
     /**
      * 使用table去写入
      * <p>