Java Poi 在Excel中输出特殊符号的实现方法

最近的工作围绕报表导出，并没有集成相应的报表插件，只是使用了Poi。其中有一个需求，Excel中导出特殊符号，如√、×等。在网上找寻了许久，没有相关资料，故记录分享一下。

思考良久，走了不少弯路，最后受 System.out.println() 启发，实现方式真的超级简单。每一个特殊符号，都对应一个Unicode编码，我们只需要将特定的符号，转变成Unicode编码，进行输出即可。

相应的代码输出：

cell.setCellValue("\u221A");

另附自己编写的Excel工具类，支持单表、主子表(可定制主表在前还是在后)、图片、特殊符号等。

<dependency>
  <groupId>org.apache.poi</groupId>
  <artifactId>poi</artifactId>
  <version>4.1.2</version>
</dependency>
<dependency>
  <groupId>org.apache.poi</groupId>
  <artifactId>poi-ooxml</artifactId>
  <version>4.1.2</version>
</dependency>
<dependency>
  <groupId>org.apache.poi</groupId>
  <artifactId>poi-ooxml-schemas</artifactId>
  <version>4.1.2</version>
</dependency>

package com.king.tools.util;
import java.util.HashMap;
import java.util.Map;

/**
 * @author ππ
 * @date 2020-6-22 17:03
 * 导出的Excel中，百分比
 */

public class ExcelPercentField {
  public final static Map<String,String> percentFiledMap = new HashMap<>();
  static {
  		// 根据实际情况进行设置
    percentFiledMap.put("a","a");
    percentFiledMap.put("b","b");
    percentFiledMap.put("c","c");
  }
}

package com.king.tools.util;

import org.apache.poi.hssf.usermodel.*;
import org.apache.poi.hssf.util.HSSFColor;
import org.apache.poi.ss.usermodel.*;
import org.apache.poi.ss.util.CellRangeAddress;
import org.apache.poi.ss.util.RegionUtil;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;

import javax.servlet.http.HttpServletResponse;
import java.io.FileNotFoundException;
import java.io.FileOutputStream;
import java.io.IOException;
import java.io.OutputStream;
import java.lang.reflect.Method;
import java.util.*;

/**
 * @author ππ
 * @date 2020-6-10 14:45
 * excel 导出通用类
 * 采用反射生成
 * 目前仅支持导出slx，暂不支持导出xlsx格式
 */

public class ExcelExport<T> {
  Logger logger = LoggerFactory.getLogger(ExcelExport.class);
  private HSSFWorkbook workbook;
  private HSSFSheet sheet;
  private int rowNum;
  private HSSFPatriarch patriarch ;
  private String fileName;
  private int version;

  public ExcelExport(){}
  public ExcelExport(String fileName, int version) {
    this.fileName = fileName;
    this.version = version;
  }

  /**
   * 导出Excel到指定位置
   * @param fields 字段集合 主表key为entity,子表key为children
   * @param dataset 数据集合 注意：如果为主子表，主表中，子表集合对应的属性名必须为children,反射使用的children进行映射，可修改
   * @param path  文件路径
   */
  public void exportExcel(String title, Map<String,List<String>> fields, Collection<T> dataset, String path,boolean childBefore){
    createExcelHSSF(title,fields,null,dataset,DateUtils.YYYY_MM_DD,path,childBefore);
  }

  /**
   * 导出Excel到指定位置
   * @param fields 字段集合 主表key为entity,子表key为children
   * @param header 表头数组
   * @param dataset 数据集合 注意：如果为主子表，主表中，子表集合对应的属性名必须为children,反射使用的children进行映射，可修改
   * @param path  文件路径
   * @param childBefore 子表在前 默认false
   */
  public void exportExcel(String title,Map<String,List<String>> fields,String[] header,Collection<T> dataset,String path,boolean childBefore){
    createExcelHSSF(title,fields,header,dataset,DateUtils.YYYY_MM_DD,path,childBefore);
  }

  /**
   * 导出Excel到指定位置
   * @param fields 字段集合 主表key为entity,子表key为children
   * @param header 表头数组
   * @param dataset 数据集合 注意：如果为主子表，主表中，子表集合对应的属性名必须为children,反射使用的children进行映射，可修改
   * @param pattern 日期格式
   * @param path  文件路径
   * @param childBefore 子表在前
   */
  public void exportExcel(String title,Map<String,List<String>> fields,String[] header,Collection<T> dataset,String pattern,String path,boolean childBefore){
    createExcelHSSF(title,fields,header,dataset,pattern,path,childBefore);
  }

  /**
   * 导出文件到本地
   * @param fields 字段集合 主表key为entity,子表key为children
   * @param dataset 数据集合 注意：如果为主子表，主表中，子表集合对应的属性名必须为children,反射使用的children进行映射，可修改
   * @param response http
   */
  public void exportExcel(String title,Map<String,List<String>> fields, Collection<T> dataset, HttpServletResponse response){
    createExcelHSSF(title,fields,null,dataset,DateUtils.YYYY_MM_DD,response);
  }

  /**
   * 导出文件到本地
   * @param fields 字段集合 主表key为entity,子表key为children
   * @param header 表头数组
   * @param dataset 数据集合 注意：如果为主子表，主表中，子表集合对应的属性名必须为children,反射使用的children进行映射，可修改
   * @param response http
   */
  public void exportExcel(String title, Map<String,List<String>> fields, String[] header, Collection<T> dataset, HttpServletResponse response){
    createExcelHSSF(title,fields,header,dataset,DateUtils.YYYY_MM_DD,response);
  }

  /**
   * 导出文件到本地
   * @param fields 字段集合 主表key为entity,子表key为children
   * @param header 表头数组
   * @param dataset 数据集合 注意：如果为主子表，主表中，子表集合对应的属性名必须为children,反射使用的children进行映射，可修改
   * @param pattern 日期格式
   * @param response http
   */
  public void exportExcel(String title, Map<String,List<String>> fields, String[] header, Collection<T> dataset, String pattern, HttpServletResponse response){
    createExcelHSSF(title,fields,header,dataset,pattern,response);
  }
  /**
   * 页面下载excel
   * @param title
   * @param fields
   * @param header
   * @param dataset
   * @param pattern
   * @param response
   */
  private void createExcelHSSF(String title, Map<String,List<String>> fields, String[] header, Collection<T> dataset, String pattern, HttpServletResponse response){
    response.reset(); // 清除buffer缓存
    // 指定下载的文件名
    response.setHeader("Content-Disposition", "attachment;filename=contacts" +(StringUtils.isBlank(fileName)? DateUtils.dateTimeNow() : fileName) + ".xls");
    response.setContentType("application/vnd.ms-excel;charset=UTF-8");
    response.setHeader("Pragma", "no-cache");
    response.setHeader("Cache-Control", "no-cache");
    response.setDateHeader("Expires", 0);
    createExcel2003(title,fields,header,dataset,pattern, false);
    httpExcelHSSF(workbook,response);
  }

  /**
   * 输出到指定路径
   * @param title
   * @param fields
   * @param header
   * @param dataset
   * @param pattern
   * @param path
   * @param childBefore
   */
  private void createExcelHSSF(String title,Map<String,List<String>> fields,String[] header,Collection<T> dataset,String pattern,String path,boolean childBefore){
    createExcel2003(title,fields,header,dataset,pattern,childBefore);
    ioExcelHSSF(workbook,path);
  }

  /**
   * 公共方法，创建excel 2003版
   * @param title
   * @param fields
   * @param header
   * @param dataset
   * @param pattern
   * @param childBefore
   */
  private void createExcel2003(String title, Map<String, List<String>> fields, String[] header, Collection<T> dataset, String pattern, boolean childBefore){
    // 初始化构建
    initWorkBook();
    // 生成样式
    HSSFCellStyle titleStyle = getTitleStyle(workbook);
    HSSFCellStyle headerStyle = getHeaderStyle(workbook);
    HSSFCellStyle normalStyle = getNormalStyle(workbook);
    HSSFCellStyle footerStyle = getFooterStyle(workbook);
    HSSFCellStyle percentStyle = createPercentStyle(workbook);
    // 创建表头
    createTableTitle(title,header.length-1,titleStyle);
    // 生成标题行
    createTableHead(header,headerStyle);
    // 迭代集合
    Iterator it = dataset.iterator();
    // 获取主表属性字段
    List<String> entityFields = fields.get("entity");
    // 获取子表属性字段
    List<String> childFields = fields.get("children");
    // 主表字段长度
    int entityColumnLength = entityFields.size();
    int childColumnLength = 0;
    if(childFields !=null){
      childColumnLength = childFields.size();
    }
    // 合并行
    int rowspan = 0;
    // 每个对象的子表数据
    Object children = null;
    HSSFRow row;
    HSSFCell cell;
    while (it.hasNext()){
      rowNum ++;
      T t = (T) it.next();
      row = sheet.createRow(rowNum);
      // 确定合并行数
      if(childFields !=null && childFields.size() > 0){
        children = getValue(t,"children");
        if(children !=null && ((ArrayList)children).size()>0){
          rowspan = ((ArrayList)children).size()-1;
        }
      }
      // 主表字段
      for(int i = 0; i <entityFields.size(); i++){
        Object value = getValue(t,entityFields.get(i));
        // 创建单元格
        if(childBefore){
          if(ExcelPercentField.percentFiledMap.containsKey(entityFields.get(i))){
            createTableCell(row.createCell(i+childColumnLength),value,percentStyle,pattern,rowspan);
          }else{
            createTableCell(row.createCell(i+childColumnLength),value,normalStyle,pattern,rowspan);
          }
        }else{
          if(ExcelPercentField.percentFiledMap.containsKey(entityFields.get(i))){
            createTableCell(row.createCell(i),value,percentStyle,pattern,rowspan);
          }else{
            createTableCell(row.createCell(i),value,normalStyle,pattern,rowspan);
          }
        }
      }
      // 子表字段
      if(childFields !=null && childFields.size() > 0){
        if(children !=null ){
          List list = (ArrayList)children;
          for(int i = 0;i <list.size(); i++){
            if(i >0){
              rowNum++;
              row = sheet.createRow(rowNum);
            }
            for(int j = 0;j<childFields.size();j++){
              Object value = getValue(list.get(i),childFields.get(j));
              if(childBefore){
                if(ExcelPercentField.percentFiledMap.containsKey(childFields.get(j))){
                  createTableCell(row.createCell(j ),value,percentStyle,pattern,rowspan);
                }else{
                  createTableCell(row.createCell(j ),value,normalStyle,pattern,rowspan);
                }
              }else{
                if(ExcelPercentField.percentFiledMap.containsKey(childFields.get(j))){
                  createTableCell(row.createCell(j +entityColumnLength),value,percentStyle,pattern,rowspan);
                }else{
                  createTableCell(row.createCell(j +entityColumnLength),value,normalStyle,pattern,rowspan);
                }

              }
            }
          }
        }
      }
      // 如果需要合并行
      if(rowspan > 0){
        for(int i = 0;i<entityFields.size();i++){
          CellRangeAddress cellRange = null;
          if(childBefore){
            cellRange= new CellRangeAddress(rowNum-rowspan,rowNum,i+childColumnLength,i+childColumnLength);
          }else{
            cellRange = new CellRangeAddress(rowNum-rowspan,rowNum,i,i);
          }
          sheet.addMergedRegion(cellRange);
          //添加边框
          RegionUtil.setBorderTop(BorderStyle.THIN, cellRange, sheet);
          RegionUtil.setBorderBottom(BorderStyle.THIN, cellRange, sheet);
          RegionUtil.setBorderLeft(BorderStyle.THIN, cellRange, sheet);
          RegionUtil.setBorderRight(BorderStyle.THIN, cellRange, sheet);
          RegionUtil.setTopBorderColor(HSSFColor.HSSFColorPredefined.GREEN.getIndex(),cellRange,sheet);
          RegionUtil.setBottomBorderColor(HSSFColor.HSSFColorPredefined.GREEN.getIndex(),cellRange,sheet);
          RegionUtil.setLeftBorderColor(HSSFColor.HSSFColorPredefined.GREEN.getIndex(),cellRange,sheet);
          RegionUtil.setRightBorderColor(HSSFColor.HSSFColorPredefined.GREEN.getIndex(),cellRange,sheet);
        }
      }
    }
    sheet.autoSizeColumn(2);
    setSizeColumn(sheet,entityColumnLength+childColumnLength);
  }
  /**
   * 初始化构建工作簿
   */
  private void initWorkBook(){
    // 创建一个工作簿
    workbook = HSSFWorkbookFactory.createWorkbook();
    // 创建一个sheet
    sheet = workbook.createSheet();
    // 默认表格列宽
    sheet.setDefaultColumnWidth(18);
    patriarch = sheet.createDrawingPatriarch();
  }
  /**
   * 创建Excel标题
   * @param title 标题
   * @param colspan 合并列
   * @param headerStyle 样式
   */
  private void createTableTitle(String title,int colspan, HSSFCellStyle headerStyle) {
    if(StringUtils.isBlank(title)){
      return;
    }
    HSSFRow row = sheet.createRow(rowNum);
    row.setHeightInPoints(30f);
    HSSFCell cell = row.createCell(0);
    sheet.addMergedRegion(new CellRangeAddress(rowNum,rowNum,0,colspan));
    cell.setCellStyle(headerStyle);
    cell.setCellValue(title);
    rowNum ++;
  }
  /**
   * 创建Excel表头
   * @param header
   * @param headerStyle
   */
  private void createTableHead(String[] header, HSSFCellStyle headerStyle) {
    if(header ==null || header.length <1){
      return;
    }
    HSSFRow row = sheet.createRow(rowNum);
    HSSFCell cell;
    for (int i = 0; i < header.length; i++){
      cell = row.createCell(i);
      cell.setCellStyle(headerStyle);
      cell.setCellValue(header[i]);
      cell.setCellType(CellType.STRING);
    }
  }

  /**
   * 创建单元格
   * @param cell
   * @param value
   * @param normalStyle
   */
  private void createTableCell(HSSFCell cell, Object value, HSSFCellStyle normalStyle, String pattern, int rowspan) {
    cell.setCellStyle(normalStyle);
    if (value ==null){
      return;
    }
    if(value instanceof Number){
      cell.setCellType(CellType.NUMERIC);
      cell.setCellValue(Double.parseDouble(value.toString()));
    //日期
    } else if(value instanceof Date){
      cell.setCellType(CellType.STRING);
      cell.setCellValue(DateUtils.parseDateToStr(pattern,(Date)value));
    // 图片
    } else if(value instanceof byte[]){
      cell.getRow().setHeightInPoints(80);
      sheet.setColumnWidth(cell.getColumnIndex(),(short) (34.5 * 110));
      HSSFClientAnchor anchor = new HSSFClientAnchor(0, 0,
          1023, 255, (short) cell.getColumnIndex(), rowNum, (short) cell.getColumnIndex(), rowNum);
      anchor.setAnchorType(ClientAnchor.AnchorType.MOVE_DONT_RESIZE);
      patriarch.createPicture(anchor, workbook.addPicture(
          (byte[])value, HSSFWorkbook.PICTURE_TYPE_JPEG));

    }else if(value instanceof Boolean){
      cell.setCellType(CellType.STRING);
      if((boolean)value){
        cell.setCellValue("\u221A");
      }
      // 全部当作字符串处理
    }else{
      cell.setCellType(CellType.STRING);
      cell.setCellValue(new HSSFRichTextString(String.valueOf(value)));
    }
  }

  /**
   * 创建标题行
   * @param workbook
   * @return
   */
  private HSSFCellStyle getTitleStyle(HSSFWorkbook workbook) {
    HSSFCellStyle style = getNormalStyle(workbook);
    style.getFont(workbook).setFontHeightInPoints((short)12);
    style.setAlignment(HorizontalAlignment.CENTER);
    style.setVerticalAlignment(VerticalAlignment.CENTER);
    return style;
  }

  /**
   * 创建尾部合计行
   * @param workbook
   * @return
   */
  private HSSFCellStyle getFooterStyle(HSSFWorkbook workbook) {
    HSSFCellStyle style = getNormalStyle(workbook);
    style.getFont(workbook).setFontHeightInPoints((short)12);
    style.setAlignment(HorizontalAlignment.CENTER);
    style.setVerticalAlignment(VerticalAlignment.CENTER);
    style.setFillForegroundColor(IndexedColors.LIME.getIndex());
    style.setFillPattern(FillPatternType.SOLID_FOREGROUND);
    return style;
  }

  /**
   * 创建表头样式
   * @param workbook
   * @return
   */
  private HSSFCellStyle getHeaderStyle(HSSFWorkbook workbook) {
    HSSFCellStyle style = getNormalStyle(workbook);
    style.getFont(workbook).setFontHeightInPoints((short)11);
    style.setAlignment(HorizontalAlignment.CENTER);
    style.setVerticalAlignment(VerticalAlignment.CENTER);
    style.setFillForegroundColor(IndexedColors.LIME.getIndex());
    style.setFillPattern(FillPatternType.SOLID_FOREGROUND);
    HSSFPalette palette = workbook.getCustomPalette();
    palette.setColorAtIndex(IndexedColors.LIME.getIndex(),(byte)198,(byte)224,(byte)180);
    return style;
  }

  /**
   * 百分比格式
   * @param workbook
   * @return
   */
  private HSSFCellStyle createPercentStyle(HSSFWorkbook workbook){
    HSSFCellStyle style = getNormalStyle(workbook);
    style.setDataFormat(HSSFDataFormat.getBuiltinFormat("0.00%"));
    return style;
  }

  /**
   * 创建普通样式
   * @param workbook
   * @return
   */
  private HSSFCellStyle getNormalStyle(HSSFWorkbook workbook){
    // 创建字体
    HSSFFont font = workbook.createFont();
    font.setFontHeightInPoints((short)10);
    // 构建样式
    HSSFCellStyle style = workbook.createCellStyle();
    // 设置边框
    style.setBorderTop(BorderStyle.THIN);
    style.setBorderRight(BorderStyle.THIN);
    style.setBorderBottom(BorderStyle.THIN);
    style.setBorderLeft(BorderStyle.THIN);
    style.setTopBorderColor(HSSFColor.HSSFColorPredefined.BLACK.getIndex());
    style.setRightBorderColor(HSSFColor.HSSFColorPredefined.BLACK.getIndex());
    style.setBottomBorderColor(HSSFColor.HSSFColorPredefined.BLACK.getIndex());
    style.setLeftBorderColor(HSSFColor.HSSFColorPredefined.BLACK.getIndex());
    style.setAlignment(HorizontalAlignment.CENTER);
    style.setVerticalAlignment(VerticalAlignment.CENTER);
    style.setFont(font);
    // 字体默认换行
    style.setWrapText(true);
    return style;
  }

  /**
   * 反射获取值
   * @param t
   * @param fieldName
   * @param <E>
   * @return
   */
  private <E> Object getValue(E t,String fieldName){
    String methodName = "get"
        + fieldName.substring(0, 1).toUpperCase()
        + fieldName.substring(1);
    try {
      Method method = t.getClass().getMethod(methodName);
      method.setAccessible(true);
      Object value = method.invoke(t);
      return value;
    } catch (Exception e) {
      e.printStackTrace();
    }
    return null;
  }
  /**
   * 输出IO流
   * @param workbook
   * @param path
   * @return
   */
  private void ioExcelHSSF(HSSFWorkbook workbook, String path){
    OutputStream ops =null;
    if(StringUtils.isBlank(fileName)){
      path = path + DateUtils.dateTimeNow() +".xls";
    } else {
      path = path + fileName + ".xls";
    }
    try {
      ops = new FileOutputStream(path);
      workbook.write(ops);
    } catch (FileNotFoundException e) {
      e.printStackTrace();
    } catch (IOException e) {
      e.printStackTrace();
    }finally {
      if(ops != null){
        try {
          ops.close();
        } catch (IOException e) {
          e.printStackTrace();
        }
      }
    }
  }

  private void httpExcelHSSF(HSSFWorkbook workbook, HttpServletResponse response){
    OutputStream ops = null;
    try {
      ops = response.getOutputStream();
      response.flushBuffer();
      workbook.write(ops);
    } catch (IOException e) {
      e.printStackTrace();
      if(ops !=null){
        try {
          ops.close();
        } catch (IOException ex) {
          ex.printStackTrace();
        }
      }
    }
  }

  /**
   * 自适应列宽
   * @param sheet
   * @param size 列数
   */
  private void setSizeColumn(HSSFSheet sheet, int size) {
    for(int i =0;i<size;i++){
      int columnWidth = sheet.getColumnWidth(i) / 256;
      for (int rowNum = 1; rowNum <= sheet.getLastRowNum(); rowNum++) {
        HSSFRow currentRow;
        //当前行未被使用过
        if (sheet.getRow(rowNum) == null) {
          currentRow = sheet.createRow(rowNum);
        } else {
          currentRow = sheet.getRow(rowNum);
        }

        if (currentRow.getCell(i) != null) {
          HSSFCell currentCell = currentRow.getCell(i);
//          if(rowNum==sheet.getLastRowNum()){
//            HSSFCellStyle style = currentCell.getCellStyle();
//            style.setFillForegroundColor(IndexedColors.LIME.getIndex());
//            style.setFillPattern(FillPatternType.SOLID_FOREGROUND);
//            currentCell.setCellStyle(style);
//          }
          if (currentCell.getCellType() == CellType.STRING) {
            int length = currentCell.getStringCellValue().getBytes().length;
            if (columnWidth < length) {
              columnWidth = length;
            }
          }
        }
      }
      sheet.setColumnWidth(i, columnWidth * 256);
    }
  }
}

效果图如下：

但仍遇到一个问题，主子表结构导出，如果图片在主表，合并行之后，图片并不会居中，并且第一行会被撑开，有没有比较简单的方式进行处理(不想重新计算锚点，然后定高输出)？

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