easyexcel实现自定义的策略类, 最后追加错误提示列, 自适应列宽,自动合并重复单元格, 美化表头

- 原版
- 表头和表体字体美化
- 自动拼接错误提示列
- 自适应宽度
- 自动合并单元格
- - - 使用Easyexcel
    - 使用poi导出

在后台管理开发的工作中,离不开的就是导出excel了. 如果是简单的导出, 直接easyexcel三四行代码就可以, 但是如果产品业务需要更美观的话, 就需要我们自己去做一些改造
以下代码为自己反复调试后暂用的代码, 如果后面还有优化的话会更新.

原版

首先看下效果对比

原版

乍一看还行, 但是有几个问题, 表头字体大了点, 列宽一样,要自己每个去调整. ,重复单元格想要合并
以及我们有时候, 需要校验导入的模板是否正确, 错误的话想在后面加提示. 所以不得不自己自动手了

表头和表体字体美化

在这里插入图片描述

直接上代码

 
import com.alibaba.excel.write.metadata.style.WriteCellStyle;
import com.alibaba.excel.write.metadata.style.WriteFont;
import com.alibaba.excel.write.style.HorizontalCellStyleStrategy;
import org.apache.poi.ss.usermodel.BorderStyle;
import org.apache.poi.ss.usermodel.HorizontalAlignment;
import org.apache.poi.ss.usermodel.IndexedColors;
import org.apache.poi.ss.usermodel.VerticalAlignment;

import java.util.List;
import java.util.Map;

/**
 * ExcelStyleTool
 *
 * @author zgd
 * @date 2024/3/13 17:16
 */
public class ExcelStyleTool {

    /**
     * 设置excel样式
     */
    public static HorizontalCellStyleStrategy getStyleStrategy() {
        // 头的策略  样式调整
        WriteCellStyle headWriteCellStyle = new WriteCellStyle();
        //设置头部样式
        setHeadStyle(headWriteCellStyle, true, true);
        // 设置细边框
        setBorder(headWriteCellStyle);
        //表头字体样式
        WriteFont headWriteFont = getHeadFont(IndexedColors.SKY_BLUE.getIndex());
        headWriteCellStyle.setWriteFont(headWriteFont);

        // 内容的策略
        WriteCellStyle contentStyle = new WriteCellStyle();
        //设置内容样式
        setHeadStyle(headWriteCellStyle, false, false);
        //设置边框
//        setBorder(contentStyle);
        //内容字体
        WriteFont contentWriteFont = getContentFont();
        contentStyle.setWriteFont(contentWriteFont);
        // 这个策略是 头是头的样式 内容是内容的样式 其他的策略可以自己实现
        return new HorizontalCellStyleStrategy(headWriteCellStyle, contentStyle);
    }




    /**
     * 获取表头字体
     * @param color
     * @return
     */
    private static WriteFont getHeadFont(Short color){
        //表头字体样式
        WriteFont headWriteFont = new WriteFont();
        // 头字号
        headWriteFont.setFontHeightInPoints((short) 10);
        // 字体样式
        headWriteFont.setFontName("微软雅黑");
        // 字体颜色
        headWriteFont.setColor(color);
        // 字体加粗
        headWriteFont.setBold(true);
        return headWriteFont;
    }

    /**
     * 获取内容字体
     * @return
     */
    private static WriteFont getContentFont(){
        //内容字体
        WriteFont contentWriteFont = new WriteFont();
        contentWriteFont.setFontHeightInPoints((short) 9);
        contentWriteFont.setFontName("Arial");
        contentWriteFont.setBold(false);
        return contentWriteFont;
    }

    /**
     *
     * @param cellStyle
     * @param wrappedFlag   自动换行标识，true:开启自动换行
     * @param centerFlag    水平居中开关，true:开启水平居中
     */
    private static void setHeadStyle(WriteCellStyle cellStyle, boolean wrappedFlag, boolean centerFlag){
        // 头背景 白色
        cellStyle.setFillForegroundColor(IndexedColors.WHITE.getIndex());
        if(wrappedFlag){
            // 自动换行
            cellStyle.setWrapped(true);
        }
        if(centerFlag){
            // 水平对齐方式
            cellStyle.setHorizontalAlignment(HorizontalAlignment.CENTER);
        }
        // 垂直对齐方式
        cellStyle.setVerticalAlignment(VerticalAlignment.CENTER);
    }

    /**
     * 设置边框
     * @param cellStyle
     */
    private static void setBorder(WriteCellStyle cellStyle){
        // 设置细边框
        cellStyle.setBorderBottom(BorderStyle.THIN);
        cellStyle.setBorderLeft(BorderStyle.THIN);
        cellStyle.setBorderRight(BorderStyle.THIN);
        cellStyle.setBorderTop(BorderStyle.THIN);
        // 设置边框颜色 25灰度
        cellStyle.setBottomBorderColor(IndexedColors.BLACK.getIndex());
        cellStyle.setTopBorderColor(IndexedColors.BLACK.getIndex());
        cellStyle.setLeftBorderColor(IndexedColors.BLACK.getIndex());
        cellStyle.setRightBorderColor(IndexedColors.BLACK.getIndex());
    }

    /**
     * 得到自定义单元格策略, 内容居中
     * @return
     */
    public static BeautyStyleStrategy getBeautyCellStyleStrategyCenter(){
        //灰色表头样式
        WriteCellStyle headWriteCellStyle = new WriteCellStyle();
        setHeadStyle(headWriteCellStyle, true, true);
        setBorder(headWriteCellStyle);
        WriteFont headWriteFontBlue = getHeadFont(IndexedColors.BLACK.getIndex());
        headWriteCellStyle.setWriteFont(headWriteFontBlue);
        //背景色
        headWriteCellStyle.setFillForegroundColor(IndexedColors.GREY_25_PERCENT.getIndex());

        //居中对其内容样式
        WriteFont contentWriteFont2 = getContentFont();
        WriteCellStyle contentStyleCenter = new WriteCellStyle();
        contentStyleCenter.setHorizontalAlignment(HorizontalAlignment.CENTER);
        contentStyleCenter.setVerticalAlignment(VerticalAlignment.CENTER);
//        setBorder(contentStyleCenter);
        contentStyleCenter.setWriteFont(contentWriteFont2);
        return new BeautyStyleStrategy(
                headWriteCellStyle,
                null,contentStyleCenter);
    }


    /**得到内容左对齐的策略
     * @return
     */
    public static BeautyStyleStrategy getBeautyCellStyleStrategyLeft(){
        //灰色表头样式
        WriteCellStyle headWriteCellStyle = new WriteCellStyle();
        setHeadStyle(headWriteCellStyle, true, true);
        setBorder(headWriteCellStyle);
        WriteFont headWriteFont = getHeadFont(IndexedColors.BLACK.getIndex());
        headWriteCellStyle.setWriteFont(headWriteFont);
        //背景色
        headWriteCellStyle.setFillForegroundColor(IndexedColors.GREY_25_PERCENT.getIndex());

        //内容文字
        WriteFont contentWriteFont = getContentFont();
        //左对齐内容样式
        WriteCellStyle contentStyleLeft = new WriteCellStyle();
        contentStyleLeft.setHorizontalAlignment(HorizontalAlignment.LEFT);
        contentStyleLeft.setVerticalAlignment(VerticalAlignment.CENTER);
//        setBorder(contentStyleLeft);
        contentStyleLeft.setWriteFont(contentWriteFont);
        return new BeautyStyleStrategy(
                headWriteCellStyle,
                contentStyleLeft,null);
    }

    public static CustomColumnWidthStyleStrategy getColumnWidthStrategy(int minBytes, int maxBytes){
        return new CustomColumnWidthStyleStrategy(minBytes,maxBytes);
    }
    public static CustomColumnWidthStyleStrategy getAutoBeautyColumnWidthStrategy(){
        //比较合适的自适应宽度
        return new CustomColumnWidthStyleStrategy(8,50);
    }

    /**
     * @param headIdx  标题行
     * @param colIdx   错误所在列. 下标从0开始. 如果没指定,自动取标题行的下一列
     * @param errTitle
     * @param errMap   错误信息,key是内容list的下标(为了方便list遍历时传值),最终它的行是 headIdx+errMap+1
     */
    public static AddErrColWriteHandler getAddErrColWriteHandler(Integer headIdx, Integer colIdx, String errTitle, Map<Integer, String> errMap){
        return new AddErrColWriteHandler(headIdx, colIdx, errTitle, errMap);
    }

    /**
     *  @param headIdx  标题行
     *   @param errTitle
     *    @param errMap   错误信息,key是内容list的下标,从0开始(为了方便list遍历时传值),最终它的行是 headIdx+errMap+1
     */
    public static AddErrColWriteHandler getAddErrColWriteHandler( Integer headIdx, String errTitle, Map<Integer, String> errMap){
        return new AddErrColWriteHandler(headIdx,  errTitle, errMap);
    }

    /**
     * 获取合并单元格处理器
     * @return
     */
    public static CustomMergeCellWriteHandler getMergeHandler() {
        return new CustomMergeCellWriteHandler();
    }


    /**
     * 获取合并单元格处理器
     * @param firstRow
     * @param lastRow
     * @param firstCol
     * @param lastCol
     * @return
     */
    public static CustomMergeCellWriteHandler getMergeHandler(int firstRow, int lastRow, int firstCol, int lastCol) {
        return new CustomMergeCellWriteHandler(firstRow, lastRow, firstCol, lastCol);
    }

 
    /**
     * 获取 按列 相同的值进行合并的处理器
     * @param colList
     * @return
     */
    public static LoopColRangeWriteHandler getLoopColRangeWriteHandler(List<Integer> colList,int fromRow,int toRow) {
    	return new LoopColRangeWriteHandler(colList,fromRow,toRow);
    }
}

策略类



 
import com.alibaba.excel.metadata.Head;
import com.alibaba.excel.util.StyleUtil;
import com.alibaba.excel.write.metadata.style.WriteCellStyle;
import com.alibaba.excel.write.style.AbstractCellStyleStrategy;
import lombok.extern.slf4j.Slf4j;
import org.apache.poi.ss.usermodel.Cell;
import org.apache.poi.ss.usermodel.CellStyle;
import org.apache.poi.ss.usermodel.Workbook;

import java.util.ArrayList;
import java.util.List;

/**
 * 自定义拦截器
 */
@Slf4j
public class BeautyStyleStrategy extends AbstractCellStyleStrategy {


    //这个是 easyexcel 的蓝色表头样式
    private WriteCellStyle headWriteCellStyle;
    //这个是 easyexcel 的左对齐内容样式
    private List<WriteCellStyle> contentWriteCellStyleListLeft;
    //这个是 easyexcel 的居中对其内容样式
    private List<WriteCellStyle> contentWriteCellStyleListCenter;

    //这个是 poi 的表头样式，中间会有一步转换
    private CellStyle headCellStyle;
    //这个是 poi 的左对齐内容样式，中间会有一步转换
    private List<CellStyle> contentCellStyleListLeft;
    //这个是 poi 的居中对齐内容样式，中间会有一步转换
    private List<CellStyle> contentCellStyleListCenter;

    //斑马纹构造方法
    public BeautyStyleStrategy(WriteCellStyle headWriteCellStyle,
                                   List<WriteCellStyle> contentWriteCellStyleListLeft,List<WriteCellStyle> contentWriteCellStyleListCenter) {
        this.headWriteCellStyle = headWriteCellStyle;
        this.contentWriteCellStyleListLeft = contentWriteCellStyleListLeft;
        this.contentWriteCellStyleListCenter = contentWriteCellStyleListCenter;
    }
    //统一样式的构造方法
    public BeautyStyleStrategy(WriteCellStyle headWriteCellStyle,
                               WriteCellStyle contentWriteCellStyleLeft, WriteCellStyle contentWriteCellStyleCenter) {
        this.headWriteCellStyle = headWriteCellStyle;
        contentWriteCellStyleListLeft = new ArrayList<>();
        if (contentWriteCellStyleLeft != null){
            contentWriteCellStyleListLeft.add(contentWriteCellStyleLeft);
        }
        contentWriteCellStyleListCenter = new ArrayList<>();
        if (contentWriteCellStyleCenter != null){
            contentWriteCellStyleListCenter.add(contentWriteCellStyleCenter);
        }
    }

    //实例化后进行 easyexcel -> poi 样式的转换
    @Override
    protected void initCellStyle(Workbook workbook) {
        if (headWriteCellStyle != null) {
            headCellStyle = StyleUtil.buildHeadCellStyle(workbook, headWriteCellStyle);
        }
        if (contentWriteCellStyleListLeft != null && !contentWriteCellStyleListLeft.isEmpty()) {
            contentCellStyleListLeft = new ArrayList<CellStyle>();
            for (WriteCellStyle writeCellStyle : contentWriteCellStyleListLeft) {
                if (writeCellStyle == null){
                    continue;
                }
                contentCellStyleListLeft.add(StyleUtil.buildContentCellStyle(workbook, writeCellStyle));
            }
        }
        if (contentWriteCellStyleListCenter != null && !contentWriteCellStyleListCenter.isEmpty()) {
            contentCellStyleListCenter = new ArrayList<CellStyle>();
            for (WriteCellStyle writeCellStyle : contentWriteCellStyleListCenter) {
                if (writeCellStyle == null){
                    continue;
                }
                contentCellStyleListCenter.add(StyleUtil.buildContentCellStyle(workbook, writeCellStyle));
            }
        }
    }

    //设置表头样式
    @Override
    protected void setHeadCellStyle(Cell cell, Head head, Integer relativeRowIndex) {
        int colIndex = cell.getColumnIndex();
        //同样，根据不同的列编号选择使用不同的内容样式
        if (headCellStyle == null) {
            return;
        }
        cell.setCellStyle(headCellStyle);
    }

    //设置内容样式
    @Override
    protected void setContentCellStyle(Cell cell, Head head, Integer relativeRowIndex) {
        int rowIndex = cell.getRowIndex();
        //同样，根据不同的列编号选择使用不同的内容样式
//        if (rowIndex > 0) {
//            if (contentCellStyleListCenter == null || contentCellStyleListCenter.isEmpty()) {
//                return;
//            }
//            cell.setCellStyle(contentCellStyleListCenter.get(relativeRowIndex % contentCellStyleListCenter.size()));
//        }

        if (contentCellStyleListCenter != null && !contentCellStyleListCenter.isEmpty()) {
                cell.setCellStyle(contentCellStyleListCenter.get(0));
        }else if(contentCellStyleListLeft != null && !contentCellStyleListLeft.isEmpty()){
            cell.setCellStyle(contentCellStyleListLeft.get(0));
        }

    }



}

  EasyExcel.write(os, KnowledgePanoramaActivityExcelVO.class)
                    .sheet("配置情况")
//美化表头和表体字体
                    .registerWriteHandler(ExcelStyleTool.getBeautyCellStyleStrategyLeft())
                    .doWrite(records);

如果希望表体内容能够居中显示，只需简单地使用ExcelStyleTool.getBeautyCellStyleStrategyCenter()方法。这只是一个基础框架，可以根据实际需求自由调整颜色、字体等样式。为此，可以在ExcelStyleTool类中新建一个方法，并在该方法中创建一个新的BeautyStyleStrategy对象进行返回。
如果还希望实现每行颜色间隔不同的效果，只需在contentWriteCellStyleListLeft或contentWriteCellStyleListCenter集合中，添加多个不同的样式。随后，只需取消setContentCellStyle方法中的注释即可应用这些样式。

自动拼接错误提示列

效果:
在这里插入图片描述

可以在原excel文件的基础上(即便是有丰富样式的模板文件), 在最后加一列, 然后填充我们的错误提示信息

 
import com.alibaba.excel.write.handler.SheetWriteHandler;
import com.alibaba.excel.write.metadata.holder.WriteSheetHolder;
import com.alibaba.excel.write.metadata.holder.WriteWorkbookHolder;
import lombok.extern.slf4j.Slf4j;
import org.apache.poi.ss.usermodel.*;

import java.util.Map;

/**
 * 自定义拦截器.新增注释,第一行头加批注
 */
@Slf4j
public class AddErrColWriteHandler implements SheetWriteHandler {

    /**
     * 第几行
     */
    private final Integer headIdx;

    private Integer colIdx;

    private final String errTitle;

    private Map<Integer, String> errMap;

    /**
     * @param headIdx  标题行
     * @param colIdx   错误所在列. 下标从0开始. 如果没指定,自动取标题行的下一列
     * @param errTitle
     * @param errMap   错误信息,key是内容list的下标(为了方便list遍历时传值),最终它的行是 headIdx+errMap+1
     */
    public AddErrColWriteHandler(Integer headIdx, Integer colIdx, String errTitle, Map<Integer, String> errMap) {
        this.headIdx = headIdx  ;
        this.colIdx = colIdx;
        this.errTitle = errTitle;
        this.errMap = errMap;
    }

    /**
     * @param headIdx  标题行
     * @param errTitle
     * @param errMap   错误信息,key是内容list的下标,从0开始(为了方便list遍历时传值),最终它的行是 headIdx+errMap+1
     */
    public AddErrColWriteHandler(Integer headIdx, String errTitle, Map<Integer, String> errMap) {
        this.headIdx = headIdx  ;
        this.errTitle = errTitle;
        this.errMap = errMap;
    }


    @Override
    public void beforeSheetCreate(WriteWorkbookHolder writeWorkbookHolder, WriteSheetHolder writeSheetHolder) {

    }

    @Override
    public void afterSheetCreate(WriteWorkbookHolder writeWorkbookHolder, WriteSheetHolder writeSheetHolder) {
        int lastCellNum = 0;
        Workbook workbook = writeWorkbookHolder.getWorkbook();
        CellStyle cellStyleHeader = getCellHeaderStyle(workbook);
        for (Integer i = 0; i <= headIdx; i++) {
            Row row = writeSheetHolder.getCachedSheet().getRow(headIdx);
            if (row == null) {
                row = writeSheetHolder.getCachedSheet().createRow(headIdx);
            }
            if (colIdx == null) {
                lastCellNum = Math.max(row.getLastCellNum(),lastCellNum);
                colIdx = (int) lastCellNum;
            }
        }
        int titleRowNum = headIdx;
        if (headIdx > 0){
            //合并单元格, easyExcel从第1行开始. 然后lastRow和lastCol都不包含自身所以加一
//            writeSheetHolder.getCachedSheet().addMergedRegion(new CellRangeAddress(0,headIdx,colIdx,colIdx));
            //单元格只保留最上面的,所以指定第一行
            titleRowNum = 0;
        }
        Row row = writeSheetHolder.getCachedSheet().getRow(titleRowNum);
        Cell cell = row.getCell(colIdx);
        if (cell == null) {
            cell = row.createCell(colIdx);
        }
        cell.setCellStyle(cellStyleHeader);
        cell.setCellValue(errTitle);





        // 内容样式
        CellStyle  cellStyle =  getCellStyle(workbook);
        Sheet sheet = writeSheetHolder.getCachedSheet();
        for (Map.Entry<Integer, String> en : errMap.entrySet()) {
            int rowIdx = en.getKey() + headIdx + 1;
            Row row0 = sheet.getRow(rowIdx);
            if (row0 == null) {
                row0 = sheet.createRow(rowIdx);
            }
            // 第几列。我这里是1.正常业务根据需求传递
            Cell cell0 = row0.getCell(colIdx);
            if (cell0 == null) {
                cell0 = row0.createCell(colIdx);
            }
            cell0.setCellStyle(cellStyle);
            cell0.setCellValue(en.getValue());
        }
    }

    private CellStyle getCellStyle(Workbook workbook) {
        CellStyle cellStyle = workbook.createCellStyle();
//            cellStyle.setAlignment(HorizontalAlignment.CENTER);
        cellStyle.setVerticalAlignment(VerticalAlignment.CENTER);
        cellStyle.setFillForegroundColor(IndexedColors.WHITE.getIndex());
        Font font = workbook.createFont();
        font.setFontName("微软雅黑");
        font.setFontHeightInPoints((short) 10);
        cellStyle.setFont(font);
        return cellStyle;
    }

    private CellStyle getCellHeaderStyle(Workbook workbook) {
        // 表头样式
        CellStyle cellStyle = workbook.createCellStyle();
        cellStyle.setAlignment(HorizontalAlignment.LEFT);
        cellStyle.setVerticalAlignment(VerticalAlignment.CENTER);
        cellStyle.setFillForegroundColor(IndexedColors.WHITE.getIndex());
        Font font = workbook.createFont();
        font.setFontName("微软雅黑");
        font.setColor((short) 10);
        font.setFontHeightInPoints((short) 12);
        cellStyle.setFont(font);
        return cellStyle;
    }
}

使用, 可以使用ExcelStyleTool的静态方法, 也可以自己直接new


int headIdx = 1;
//这个key是内容list的下标,从0开始(为了方便list遍历时传值),最终它的行是 headIdx+errMap+1,value是错误信息
Map<Integer,String> errMsgMap = new HashMap<>();
for (int i = 0; i < data.length; i++, dataRow++) {
  errMsgMap.put(i,"这是错误");
}
//file是上传的文件
 InputStream is = file.getInputStream();
 //os是response的输出流或者file文件的输出流
 EasyExcel.write(os)
                    .withTemplate(is)
                    .registerWriteHandler(new AddErrColWriteHandler(headIdx, "错误信息(重新导入请删除此列)", errMsgMap))
                    .sheet()
                    .doWrite(new ArrayList());

自适应宽度

效果图:
在这里插入图片描述
可以看到可以根据列的文本长度(字体默认11的情况), 列宽有一个比较好的适应效果. 如果字体不一样, 修改calWidth方法里的计算方法.

 
import com.alibaba.excel.enums.CellDataTypeEnum;
import com.alibaba.excel.metadata.CellData;
import com.alibaba.excel.metadata.Head;
import com.alibaba.excel.util.CollectionUtils;
import com.alibaba.excel.write.metadata.holder.WriteSheetHolder;
import com.alibaba.excel.write.style.column.AbstractColumnWidthStyleStrategy;
import org.apache.poi.ss.usermodel.Cell;

import java.util.HashMap;
import java.util.List;
import java.util.Map;

public class CustomColumnWidthStyleStrategy extends AbstractColumnWidthStyleStrategy {

    private static final int MAX_COLUMN_WIDTH = 255 * 256;
    private static final int MIN_COLUMN_WIDTH = 2 * 256;

    private final int maxColumnWidth;
    private final int minColumnWidth;



    public CustomColumnWidthStyleStrategy(int minBytes,int maxBytes) {
        this.maxColumnWidth = Math.min(calWidth(maxBytes), MAX_COLUMN_WIDTH);
        this.minColumnWidth = Math.max(calWidth(minBytes), MIN_COLUMN_WIDTH);
    }

    private static int calWidth(int bytes) {
        return bytes * 256 * 2 / 3;
    }

    public CustomColumnWidthStyleStrategy() {
        this.maxColumnWidth = MAX_COLUMN_WIDTH;
        this.minColumnWidth = MIN_COLUMN_WIDTH;
    }

    private Map<Integer, Map<Integer, Integer>> cache = new HashMap<Integer, Map<Integer, Integer>>(8);

    @Override
    protected void setColumnWidth(WriteSheetHolder writeSheetHolder, List<CellData> cellDataList, Cell cell, Head head,
                                  Integer relativeRowIndex, Boolean isHead) {
        boolean needSetWidth = isHead || !CollectionUtils.isEmpty(cellDataList);
        if (!needSetWidth) {
            return;
        }
        Map<Integer, Integer> maxColumnWidthMap = cache.computeIfAbsent(writeSheetHolder.getSheetNo(), k -> new HashMap<Integer, Integer>(16));
        Integer columnWidth = dataLength(cellDataList, cell, isHead);
        if (columnWidth < 0) {
            return;
        }
        if (columnWidth > maxColumnWidth) {
            columnWidth = maxColumnWidth;
        }
        if (columnWidth < minColumnWidth) {
            columnWidth = minColumnWidth;
        }
        Integer maxColumnWidth = maxColumnWidthMap.get(cell.getColumnIndex());
        if (maxColumnWidth == null || columnWidth > maxColumnWidth) {
            maxColumnWidthMap.put(cell.getColumnIndex(), columnWidth);
            writeSheetHolder.getSheet().setColumnWidth(cell.getColumnIndex(), columnWidth);
        }
    }

    private Integer dataLength(List<CellData> cellDataList, Cell cell, Boolean isHead) {
        if (isHead) {
            //不考虑标题
            return -1;
        }
        CellData cellData = cellDataList.get(0);
        CellDataTypeEnum type = cellData.getType();
        if (type == null) {
            return minColumnWidth;
        }
        switch (type) {
            case STRING:
                return calWidth(cellData.getStringValue().getBytes().length);
            case BOOLEAN:
                return calWidth(cellData.getBooleanValue().toString().getBytes().length);
            case NUMBER:
                return calWidth(cellData.getNumberValue().toString().getBytes().length );
            default:
                return minColumnWidth;
        }
    }
}

使用方法和上面差不多, 不赘述了

自动合并单元格

效果,可以按列,将同样的内容的单元格自动合并, 如果需要按行合并, 差不多的思路实现, 这里没这个需求就没有做:
在这里插入图片描述

首先写一个公共方法. 用于针对某一列的同样内容进行合并单元格;


    public static void mergeByCol(Sheet sheet, int colIdx, int fromRowIdx,int toRowIdx) {
        mergeByCol(sheet, colIdx, fromRowIdx,toRowIdx,false,VerticalAlignment.CENTER,HorizontalAlignment.CENTER);
    }

        /**
         * 根据列,将同样的单元格合并
         * @param sheet
         * @param colIdx
         * @param fromRowIdx
         */
    public static void mergeByCol(Sheet sheet, int colIdx, int fromRowIdx,int toRowIdx,boolean wrap,VerticalAlignment verticalAlignment,HorizontalAlignment alignment) {
        Iterator<Row> it = sheet.rowIterator();
        int rows = -1;
        String lastVal = null;
        int lastRows = 0;
        while (it.hasNext()){
            Row row = it.next();
            rows++;
            if (fromRowIdx > rows){
                continue;
            }
            if (lastVal == null){
                lastRows = rows;
                lastVal = row.getCell(colIdx).getStringCellValue();
            } else {
                Cell cell = row.getCell(colIdx);
                String curVal = cell == null ? null : cell.getStringCellValue();
                if (lastVal.equals(curVal)){
                    continue;
                } else {
                    if (rows - 1 > lastRows) {
                        //合并
                        sheet.addMergedRegion(new CellRangeAddress(lastRows, rows - 1, colIdx, colIdx));
                        //设置格式
                        Cell topLeftCell = sheet.getRow(lastRows).getCell(colIdx);
                        CellStyle originStyle = topLeftCell.getCellStyle();
                        CellStyle cellStyle = sheet.getWorkbook().createCellStyle();
                        cellStyle.cloneStyleFrom(originStyle);
                        cellStyle.setVerticalAlignment(verticalAlignment);
                        cellStyle.setAlignment(alignment);
                        if (wrap){
                            cellStyle.setWrapText(true);
                        }
                    }
                    lastRows = rows;
                    lastVal = curVal;
                }
            }
        }
        //遍历所有行以后,最后判断一次
        Cell cell = sheet.getRow(toRowIdx).getCell(colIdx);
        if (cell != null && lastVal != null ){
            String curVal = cell.getStringCellValue();
            if (Objects.equals(lastVal, curVal)){
                sheet.addMergedRegion(new CellRangeAddress(lastRows, toRowIdx, colIdx, colIdx));
            }
        }

使用Easyexcel

 
import com.alibaba.excel.metadata.CellData;
import com.alibaba.excel.metadata.Head;
import com.alibaba.excel.write.handler.AbstractCellWriteHandler;
import com.alibaba.excel.write.metadata.holder.WriteSheetHolder;
import com.alibaba.excel.write.metadata.holder.WriteTableHolder;
import javafx.util.Pair;
import org.apache.poi.ss.usermodel.Cell;
import org.apache.poi.ss.usermodel.CellStyle;
import org.apache.poi.ss.usermodel.HorizontalAlignment;
import org.apache.poi.ss.usermodel.VerticalAlignment;
import org.apache.poi.ss.util.CellRangeAddress;

import java.util.List;
import java.util.Map;
import java.util.Objects;
import java.util.stream.Collectors;

/**
 * 添加合并区Handler
 */
public class LoopColRangeWriteHandler extends AbstractCellWriteHandler {
    private final Map<Integer, Pair<Integer,String>> mergeMap;
    /**
    从哪行开始,主要是跳过表头
    */
    private final Integer fromRow;
     /**
     * 标志在哪一行结束合并,最重要的是放在最后一行的时候,让系统知道将前面的合并
     */
    private final Integer toRow;

    public LoopColRangeWriteHandler(List<Integer> colList, Integer fromRow,Integer toRow) {
        mergeMap = colList.stream().collect(Collectors.toMap(i -> i, i -> new Pair<>(fromRow, "")));
        this.fromRow = fromRow;
        this.toRow = toRow;
    }


    @Override
    public void afterCellDispose(WriteSheetHolder writeSheetHolder, WriteTableHolder writeTableHolder, List<CellData> cellDataList, Cell cell, Head head, Integer relativeRowIndex, Boolean isHead) {
        String cellValue = cell.getStringCellValue();
        int columnIndex = cell.getColumnIndex();
        int rowIndex = cell.getRowIndex();
        if ((fromRow < 0 && isHead) || rowIndex < fromRow
//                || !mergeMap.containsKey(columnIndex)
        ){
            return;
        }
        if (rowIndex == toRow){
            for (Integer colIndex : colList) {
                if (colIndex == columnIndex){
                    ExcelUtil.mergeByCol(writeSheetHolder.getSheet(),colIndex,fromRow,toRow,true,VerticalAlignment.CENTER,HorizontalAlignment.LEFT);
                }
            }
        }
    }
}

然后用的话, 需要指定开始行和结束行, 结束行是为了让系统知道这是最后一行,需要对前面相同的内容进行合并了.

 EasyExcel.write(os, KnowledgePanoramaActivityExcelVO.class)
                    .sheet("配置情况")
                    //这里结束行注意别搞错了,因为下标从0开始,所以要－1
                    .registerWriteHandler(ExcelStyleTool.getLoopColRangeWriteHandler(CollectionUtil.toList( 3,4),titleRow,records.size()+titleRow-1))
                    .doWrite(records);

使用poi导出

   Sheet studyPointSheet = workbook.getSheetAt(0);
... 填充内容
//填充完内容后使用
	ExcelUtil.mergeByCol(studyPointSheet, 2,2,studyPointSheet.getLastRowNum());
    ExcelUtil.mergeByCol(studyPointSheet, 3,2,studyPointSheet.getLastRowNum());
    workbook.write(os);