下载打包多个excel表格上传到浏览器

@Override
     public List<SchoolTaskAllocation> findAll(HttpServletRequest request, HttpServletResponse response)
             throws Exception {
         List<SchoolTaskAllocation> schoolTaskAllocation =null;
         List<String> KemuList = schoolTaskAllocationDao.selectKemu();
         String serverPath = request.getSession().getServletContext().getRealPath("/") + "\\upload\\tempExcel"; // 设置下载excel的临时文件夹
         File file = new File(serverPath);
         List<File> srcFile = new ArrayList<>();
         if (!file.exists()) {
             file.mkdirs();
         }
         for (int k = 0; k < KemuList.size(); k++) {
         XSSFWorkbook hwb = new XSSFWorkbook();// 第一步，创建一个workbook（一个excel文件）
         XSSFSheet hs = hwb.createSheet("表格详情信息");// 第二步，在workbook中添加一个sheet，对应excel文件中sheet
         XSSFRow hr = hs.createRow((int) 0);// 第三部，在sheet中添加表头第0行（相当于解释字段）
         // 1.生成字体对象
         XSSFFont font = hwb.createFont();
         font.setFontName("仿宋_GB2312");
         font.setBoldweight(XSSFFont.BOLDWEIGHT_BOLD);// 粗体显示
         font.setFontHeightInPoints((short) 16);// 设置字体大小        XSSFCellStyle hcs = hwb.createCellStyle();// 第四步，设置第0行（表头）居中
         hcs.setAlignment(XSSFCellStyle.ALIGN_CENTER);// 创建居中格式
         hcs.setFont(font);        XSSFCellStyle hcs2 = hwb.createCellStyle();// 第四步，设置第0行（表头）居中
         hcs2.setAlignment(XSSFCellStyle.ALIGN_CENTER);// 创建居中格式
         // 将表头的字段放入数组当中
         String[] arr = new String[4];
         arr[0] = "学校名称";
         arr[1] = "题型";
         arr[2] = "分配题目数";
         for (int i = 0; i < arr.length; i++) {
             XSSFCell hc = hr.createCell(i);
             hc.setCellValue(arr[i]);
             hc.setCellStyle(hcs);
             hs.autoSizeColumn(i);
         }
         // excel插入表内容
         schoolTaskAllocation = schoolTaskAllocationDao.selectAllocationExcelContents();
         String subjectName = schoolTaskAllocation.get(0).getSubjectName();
         List<SchoolTaskAllocation> addList = new ArrayList<>();
         Map<String, List<SchoolTaskAllocation>> maps = new HashMap<String, List<SchoolTaskAllocation>>();
         for (int i = 0; i < schoolTaskAllocation.size(); i++) {
             if (!schoolTaskAllocation.get(i).getSubjectName().equals(subjectName)) {
                 maps.put(subjectName, addList);
                 subjectName = schoolTaskAllocation.get(i).getSubjectName();
                 addList = new ArrayList<>();
             }
             addList.add(schoolTaskAllocation.get(i));
             if (i == schoolTaskAllocation.size() - 1) {
                 maps.put(subjectName, addList);
             }
         }        
    
             if (maps.containsKey(KemuList.get(k))) {
                 List<SchoolTaskAllocation> listF = maps.get(KemuList.get(k));
                 calculateExcel(hs, listF, hcs2);
                 String title = KemuList.get(k) + ".xlsx";
                 FileOutputStream fos = new FileOutputStream(serverPath + "\\" + title);// 先
                                                                                         // new
                                                                                         // 出文件存放的位置
                 hwb.write(fos);// 写入
                 fos.close();// 关闭资源
                 srcFile.add(new File(serverPath + "\\" + title));
             }
         
         
         
         }
         // 将服务器上存放Excel的文件夹打成zip包
                 File zipfile = new File(serverPath + "\\" + "Excel" + ".zip");
                 zipFiles(srcFile, zipfile);// 实现将多个excel打包成zip文件
                 // 下载
                 downFile(response, serverPath, "Excel" + ".zip");
         return schoolTaskAllocation;
     }    private void downFile(HttpServletResponse response, String serverPath, String str) {
         try {
             String path = serverPath + "\\" + str;
             File file = new File(path);
             if (file.exists()) {
                 InputStream ins = new FileInputStream(path);
                 BufferedInputStream bins = new BufferedInputStream(ins);// 放到缓冲流里面
                 OutputStream outs = response.getOutputStream();// 获取文件输出IO流
                 BufferedOutputStream bouts = new BufferedOutputStream(outs);
                 response.setContentType("application/ostet-stream");// 设置response内容的类型
                 response.setHeader("Content-disposition", "attachment;filename=" + URLEncoder.encode(str, "UTF-8"));// 设置头部信息
                 int bytesRead = 0;
                 byte[] buffer = new byte[8192];
                 // 开始向网络传输文件流
                 while ((bytesRead = bins.read(buffer, 0, 8192)) != -1) {
                     bouts.write(buffer, 0, bytesRead);
                 }
                 bouts.flush();// 这里一定要调用flush()方法
                 ins.close();
                 bins.close();
                 outs.close();
                 bouts.close();
             } else {
                 response.sendRedirect("../error.jsp");
             }
         } catch (IOException e) {
             e.printStackTrace();
         } finally {
             File file1 = new File(serverPath);
             deleteExcelPath(file1); // 删除临时目录
         }
     }    private boolean deleteExcelPath(File file) {
         String[] files = null;
         if (file != null) {
             files = file.list();
         }        if (file.isDirectory()) {
             for (int i = 0; i < files.length; i++) {
                 boolean bol = deleteExcelPath(new File(file, files[i]));
                 if (bol) {
                     System.out.println("删除成功!");
                 } else {
                     System.out.println("删除失败!");
                 }
             }
         }
         return file.delete();    }
    private void zipFiles(List<File> srcFile, File zipfile) {
         byte[] buf = new byte[1024];
         try {
             // Create the ZIP file
             ZipOutputStream out = new ZipOutputStream(new FileOutputStream(zipfile));
             // Compress the files
             for (int i = 0; i < srcFile.size(); i++) {
                 File file = srcFile.get(i);
                 FileInputStream in = new FileInputStream(file);
                 // Add ZIP entry to output stream.
                 out.putNextEntry(new ZipEntry(file.getName()));
                 // Transfer bytes from the file to the ZIP file
                 int len;
                 while ((len = in.read(buf)) > 0) {
                     out.write(buf, 0, len);
                 }
                 // Complete the entry
                 out.closeEntry();
                 in.close();
             }
             // Complete the ZIP file
             out.close();
         } catch (IOException e) {
             e.printStackTrace();
         }