java web 读取数据库数据写入Excel返回浏览器下载

 @RequestMapping(value = "/download", method = RequestMethod.GET)
     public void downstudents(HttpServletRequest request, HttpServletResponse response) throws IOException {
         // 一、从后台拿数据
         List<Dept> list = null;
         list=ds.list();
         try {
             // 二、 数据转成excel
             request.setCharacterEncoding("UTF-8");
             response.setCharacterEncoding("UTF-8");
             response.setContentType("application/x-download");

             String fileName = "dept.xls";
             fileName = URLEncoder.encode(fileName, "UTF-8");
             response.addHeader("Content-Disposition", "attachment;filename=" + fileName);
             // 第一步：定义一个新的工作簿
             HSSFWorkbook wb = new HSSFWorkbook();
             // 第二步：创建一个Sheet页
             HSSFSheet sheet = wb.createSheet("deptsheet");
             HSSFCellStyle style=wb.createCellStyle();
             style.setAlignment(HSSFCellStyle.ALIGN_CENTER);//设置居中(无效)
             sheet.setDefaultRowHeight((short) (256));// 设置行高
             sheet.setColumnWidth(0, 2000);// 设置列宽
             sheet.setColumnWidth(1, 5000);
             sheet.setColumnWidth(2, 5500);
             sheet.setColumnWidth(3, 5500);

             HSSFFont font = wb.createFont();
             font.setFontName("宋体");//设置字体
             font.setFontHeightInPoints((short) 16);//设置文字大小

             HSSFRow row = sheet.createRow(0);
             HSSFCell cell = row.createCell(0);
             cell.setCellValue("序号");
             cell = row.createCell(1);
             cell.setCellValue("部门编号");
             cell = row.createCell(2);
             cell.setCellValue("部门名称");
             cell = row.createCell(3);
             cell.setCellValue("地址");

             HSSFRow rows;
             HSSFCell cells;
             for (int i = 0; i < list.size(); i++) {
                 // 第三步：在这个sheet页里创建一行
                 rows = sheet.createRow(i + 1);
                 // 第四步：在该行创建一个单元格
                 cells = rows.createCell(0);
                 // 第五步：在该单元格里设置值
                 cells.setCellValue(i+1);
                 cells = rows.createCell(1);
                 cells.setCellValue(list.get(i).getDeptno());
                 cells = rows.createCell(2);
                 cells.setCellValue(list.get(i).getDname());
                 cells = rows.createCell(3);
                 cells.setCellValue(list.get(i).getLoc());

             }

             OutputStream out = response.getOutputStream();
             wb.write(out);
             out.close();
             wb.cloneSheet(0);
         } catch (IOException e) {
             e.printStackTrace();
         }
     }

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