java导出Excel通过response返回Excel.xls文件

 

import org.apache.poi.hssf.usermodel.HSSFWorkbook;
import java.io.File;
import java.io.FileOutputStream;
import java.io.OutputStream;
import javax.servlet.http.HttpServletResponse;


public String export(Record record, HttpServletResponse response) throws Exception {
   List list = selList(record);
   //生成Excel
   HSSFWorkbook workbook = null;
   ExcelUtil excelUtil = new ExcelUtil();
   List> mapList = this.getMapList(list);
   String saveBaseUrl = FileUtils.getProjectPath() + File.separator;
   String timeStr = System.currentTimeMillis();
   workbook = excelUtil.mapListToExcel(workbook, mapList, "统计");

   if (workbook != null) {
      try {
         //将excel写到文件夹中
         String fileName = UUIDGenerator.getId() + ".xls";
         File excelFile = new File(saveBaseUrl + "temp" + File.separator + "exportFile" + timeStr + File.separator + fileName);
         FileUtils.createFile(excelFile.getAbsolutePath());
         OutputStream outputStream = new FileOutputStream(excelFile);
         workbook.write(outputStream);
         outputStream.flush();
         outputStream.close();
         //导出到前端
         FileUtils.downloadFile(saveBaseUrl + "temp" + File.separator + "exportFile" + timeStr + File.separator, fileName, response);
         System.out.println("导出结束");
         //删除临时文件
         File file = new File(saveBaseUrl + "temp" + File.separator + "exportFile" + timeStr + File.separator + fileName);
         FileUtils.deleteFile(file);
      } catch (IOException e) {
         e.printStackTrace();
      }
   }
   return null;
}

private List> getMapList(List list) {
   List> mapList = new ArrayList<>();
   if (list != null && list.size() > 0) {
      for (Record sta : list) {
         Map result = new LinkedHashMap<>();
         result.put("姓名", sta.getPersonName());
         result.put("学号", sta.getPersonCode());
         result.put("部门", sta.getDeptName());
         result.put("时间", sta.getSnapTime());
         mapList.add(result);
      }
   }
   return mapList;
}

---

 

以下属于工具类（可直接复制）：

工具类ExcelUtil.java

import org.apache.poi.hssf.usermodel.HSSFCell;
import org.apache.poi.hssf.usermodel.HSSFCellStyle;
import org.apache.poi.hssf.usermodel.HSSFFont;
import org.apache.poi.hssf.usermodel.HSSFRow;
import org.apache.poi.hssf.usermodel.HSSFSheet;
import org.apache.poi.hssf.usermodel.HSSFWorkbook;
import org.apache.poi.hssf.util.HSSFColor;
import java.text.SimpleDateFormat;
import java.util.ArrayList;
import java.util.Date;
import java.util.List;
import java.util.Map;

/**
 * excel工具类
 */
public class ExcelUtil {

   /*将list>转换为Excel对象*/
   public HSSFWorkbook mapListToExcel(HSSFWorkbook workbook, List> mapLists, String sheetName) {

      if (mapLists == null || mapLists.size() == 0) {
         System.out.println("结果集为null或者为空！");
         return null;
      }
      /*获取所有的列名*/
      Map map = mapLists.get(0);
      List colNames = new ArrayList<>();
      colNames.addAll(map.keySet());

      /*创建表头*/
      /*创建Excel对象*/
      if (workbook == null) {
         workbook = new HSSFWorkbook();
      }

      HSSFSheet sheet = sheetName == null ? workbook.createSheet("sheet") : workbook.createSheet(sheetName);

      HSSFCellStyle hssfCellStyle = setHeadCellStyle(workbook);

      /*创建第一行作为表头*/
      HSSFRow headRow = sheet.createRow(0);
      headRow.setHeightInPoints(18);
      for (int i = 0; i < colNames.size(); i++) {
         //设置列宽
         sheet.setColumnWidth(i, 5000);
         HSSFCell cell = headRow.createCell(i);
         cell.setCellValue(colNames.get(i));
         cell.setCellStyle(hssfCellStyle);
      }
      /*填充所有行*/
      for (int i = 0; i < mapLists.size(); i++) {
         hssfCellStyle = setCellStyle(workbook);
         HSSFRow bodyRow = sheet.createRow(i + 1);
         bodyRow.setHeightInPoints(16);
         Map rowMap = mapLists.get(i);
         for (int j = 0; j < colNames.size(); j++) {
            HSSFCell cell = bodyRow.createCell(j);
            String cellValue = getCellValue(workbook.getSheet(sheetName).getRow(0).getCell(j));
            if (rowMap.get(cellValue) instanceof Integer) {
               cell.setCellValue((Integer) rowMap.get(cellValue));
            } else if (rowMap.get(cellValue) instanceof Long) {
               cell.setCellValue((Long) rowMap.get(cellValue));
            } else if (rowMap.get(cellValue) instanceof Float) {
               cell.setCellValue((Float) rowMap.get(cellValue));
            } else if (rowMap.get(cellValue) instanceof Double) {
               cell.setCellValue((Double) rowMap.get(cellValue));
            } else if (rowMap.get(cellValue) instanceof Date) {
               cell.setCellValue(new SimpleDateFormat("yyyy-MM-dd HH:mm:ss").format(rowMap.get(cellValue)));
            } else {
               cell.setCellValue((String) rowMap.get(cellValue));
            }
            cell.setCellStyle(hssfCellStyle);
         }
      }
      return workbook;
   }

   public HSSFCellStyle setCellStyle(HSSFWorkbook workbook) {
      HSSFCellStyle style = workbook.createCellStyle();
      style.setFont(setFount(workbook));
      style.setAlignment(HSSFCellStyle.ALIGN_LEFT);// 左右居中
      style.setVerticalAlignment(HSSFCellStyle.VERTICAL_TOP);// 上下居中
      style.setWrapText(true);
      style.setLeftBorderColor(HSSFColor.BLACK.index);
      style.setBorderLeft((short) 1);
      style.setRightBorderColor(HSSFColor.BLACK.index);
      style.setBorderRight((short) 1);
      style.setBorderBottom(HSSFCellStyle.BORDER_THIN); // 设置单元格的边框为粗体
      style.setBottomBorderColor(HSSFColor.BLACK.index); // 设置单元格的边框颜色．
      style.setFillPattern(HSSFCellStyle.SOLID_FOREGROUND);
      style.setFillForegroundColor(HSSFColor.LIGHT_CORNFLOWER_BLUE.index);// 设置单元格的背景颜色．

      return style;
   }

   /*将单元格中的内容转换为字符串格式*/
   private static String getCellValue(HSSFCell cell) {
      if (cell == null) {
         return "";
      }
      String cellValue = null;
      switch (cell.getCellType()) {
         case HSSFCell.CELL_TYPE_BLANK: {
            cellValue = "";
            break;
         }
         case HSSFCell.CELL_TYPE_BOOLEAN: {
            cellValue = String.valueOf(cell.getBooleanCellValue());
            break;
         }
         case HSSFCell.CELL_TYPE_ERROR: {
            cellValue = String.valueOf(cell.getErrorCellValue());
            break;
         }
         case HSSFCell.CELL_TYPE_FORMULA: {
            cellValue = String.valueOf(cell.getCellFormula());
            break;
         }
         case HSSFCell.CELL_TYPE_NUMERIC: {
            cellValue = String.valueOf(cell.getNumericCellValue());
            break;
         }
         case HSSFCell.CELL_TYPE_STRING: {
            cellValue = String.valueOf(cell.getStringCellValue());
            break;
         }
         default:
            break;
      }
      return cellValue;
   }

   /**
    * 设置头行单元格样式
    */

   public HSSFCellStyle setHeadCellStyle(HSSFWorkbook workbook) {
      HSSFCellStyle columnHeadStyle = workbook.createCellStyle();
      columnHeadStyle.setFont(setHeadFount(workbook));
      columnHeadStyle.setAlignment(HSSFCellStyle.ALIGN_CENTER);// 左右居中
      columnHeadStyle.setVerticalAlignment(HSSFCellStyle.VERTICAL_CENTER);// 上下居中
      columnHeadStyle.setLocked(true);
      columnHeadStyle.setWrapText(true);  //自动换行
      columnHeadStyle.setLeftBorderColor(HSSFColor.BLACK.index);// 左边框的颜色
      columnHeadStyle.setBorderLeft((short) 1);// 边框的大小
      columnHeadStyle.setRightBorderColor(HSSFColor.BLACK.index);// 右边框的颜色
      columnHeadStyle.setBorderRight((short) 1);// 边框的大小
      columnHeadStyle.setBorderBottom(HSSFCellStyle.BORDER_THIN); // 设置单元格的边框为粗体
      columnHeadStyle.setBottomBorderColor(HSSFColor.BLACK.index); // 设置单元格的边框颜色
      // 设置单元格的背景颜色（单元格的样式会覆盖列或行的样式）
      columnHeadStyle.setFillPattern(HSSFCellStyle.SOLID_FOREGROUND);
      columnHeadStyle.setFillForegroundColor(HSSFColor.LEMON_CHIFFON.index);

      return columnHeadStyle;
   }

   public HSSFFont setFount(HSSFWorkbook workbook) {
      HSSFFont headfont = workbook.createFont();
      headfont.setFontName("宋体");
      headfont.setFontHeightInPoints((short) 10);// 字体大小
      headfont.setBoldweight(HSSFFont.BOLDWEIGHT_NORMAL);

      return headfont;
   }

   /**
    * 设置头行字体
    */
   public HSSFFont setHeadFount(HSSFWorkbook workbook) {
      HSSFFont columnHeadFont = workbook.createFont();
      columnHeadFont.setFontName("宋体");
      columnHeadFont.setFontHeightInPoints((short) 11);
      columnHeadFont.setBoldweight(HSSFFont.BOLDWEIGHT_BOLD);

      return columnHeadFont;
   }
}

工具类FileUtils.java

import java.io.BufferedInputStream;
import java.io.BufferedOutputStream;
import java.io.File;
import java.io.FileInputStream;
import java.io.IOException;
import java.io.OutputStream;
import javax.servlet.http.HttpServletResponse;

public class FileUtils extends org.apache.commons.io.FileUtils {
    /**
     * 递归删除文件夹
     */
    public static void deleteFile(File file) {
        if (file.exists()) {
            if (file.isFile()) {
                file.delete();
            } else if (file.isDirectory()) {
                File[] files = file.listFiles();
                if (files != null) {
                    for (File file1 : files) {
                        deleteFile(file1);
                    }
                }
                file.delete();
            }
        }
    }

    /**
     * 创建文件，如果存在多级目录，就新增目录，然后再创建文件
     *
     * @param filePath
     * @return
     */
    public static Boolean createFile(String filePath) {
        File file = new File(filePath);
        return createFile(file);
    }

    public static Boolean createFile(File file) {
        File parentFile = file.getParentFile();
        if (!parentFile.exists()) {
            parentFile.mkdirs();
        }
        if (!file.exists()) {
            try {
                file.createNewFile();
                return true;
            } catch (IOException e) {
                e.printStackTrace();
            }
        }
        return false;
    }

    /**
     * 以压缩文件导出
     *
     * @param zipName
     * @param zipFilePath
     * @param response
     */
    public static void downloadFile(String zipFilePath, String zipName, HttpServletResponse response) {
        response.setCharacterEncoding("utf-8");
        try {
            File file = new File(zipFilePath + zipName);
            // 以流的形式下载文件。
            BufferedInputStream fis = new BufferedInputStream(new FileInputStream(file.getPath()));
            byte[] buffer = new byte[fis.available()];
            fis.read(buffer);
            fis.close();
            // 清空response
            response.reset();
            OutputStream toClient = new BufferedOutputStream(response.getOutputStream());
            response.setContentType("application/octet-stream");
            response.setHeader("Content-Disposition", "attachment;filename=" + zipName);
            toClient.write(buffer);
            toClient.flush();
            toClient.close();
        } catch (IOException ex) {
            ex.printStackTrace();
        }
    }
}