java-excle详解

  1     /**
  2      * 导出餐费统计excel
  3      */
  4     public void exportAttendList(){
  5 
  6         ByteArrayOutputStream baos = null;
  7         ByteArrayInputStream bais = null;
  8         try {
  9             if (StringUtils.isBlank(param)) {
 10                 this.writeJson("0");
 11                 return;
 12             }
 13             //获取前台的参数
 14             JSONObject jo = JSONObject.parseObject(this.param);
 15             List<String> dateList = com.alibaba.fastjson.JSONArray.toJavaObject(jo.getJSONArray("dateList"), List.class);
 16             
 17             //对前台的数据进行判断
 18             Integer classId = jo.getInteger("classId");
 19             if (dateList == null || dateList.size() == 0|| classId == null) {
 20                 this.writeJson(null, EcloudConstants.Flag.FAILURE.getIndex()
 21                         + "", "");
 22                 return;
 23             }
 24             List<Map<String, Object>> list = this.getiEcloudAttendService().findEcloudAttendCountList(dateList, classId, getUserDto().getSchoolId());
 25             // 初始化参数
 26             String title = "序号,学号,姓名,连续请假次数,连续请假详情";
 27             String titleName = "index,ecloudStudentNo,userName,count,list";
 28             //设置文件导出的名称   字符串加时间拼接
 29             String fileName = "餐费统计表"+new SimpleDateFormat("yyyyMMddHHmmss").format(new Date());
 30             
 31             // 声明一个工作薄
 32             HSSFWorkbook wb = new HSSFWorkbook();
 33             // 声明一个单子并命名
 34             HSSFSheet sheet = wb.createSheet(fileName);
 35             // 给单子名称一个长度
 36             sheet.setDefaultColumnWidth((short) 15);
 37             
 38             //设置列宽
 39             sheet.setColumnWidth(0, "学号".getBytes().length * 2 * 256);
 40             sheet.setColumnWidth(4, "2017-03-13 -- 2017-03-15 ( 3天 )".getBytes().length * 1 * 256);
 41             // 生成一个样式
 42             HSSFCellStyle style = wb.createCellStyle();
 43             // 创建第一行（也可以称为表头）
 44             HSSFRow row = sheet.createRow(0);
 45             // 样式字体居中
 46             style.setAlignment(HSSFCellStyle.ALIGN_CENTER); // 居中 
 47             style.setWrapText(true);
 48 
 49             // 给表头第一行一次创建单元格
 50             int i = 0;
 51             for (String entry : title.split(",")) {
 52                 HSSFCell cell = row.createCell((short) i++);
 53                 cell.setCellValue(entry);
 54                 cell.setCellStyle(style);
 55             }
 56                     
 57             for (int b=0; b<list.size(); b++) {
 58                 Map map = list.get(b);
 59                 row = sheet.createRow(b + 1);
 60                 for (int j = 0; j < titleName.split(",").length; j++) {
 61                     HSSFCell cell = row.createCell((short) j);
 62                     String name = titleName.split(",")[j];
 63                     if (name.equals("index")) {
 64                         //记录序号    由于这个参数是递增的，所以需要自定义判断
 65                         cell.setCellValue(b + 1 + "");
 66                     } else {
 67                         //遍历请假记录
 68                         if (name.equals("list")) {
 69                             List<String> list2 = (List<String>) map.get(name);
 70                             //设置行高   使用list的大小对行高进行设置
 71                             row.setHeight((short)(list2.size()*250));
 72                             String t = "";
 73                             //把list转为我们想要的参数    并加入换行符  最后不加
 74                             for (int k = 0; k < list2.size(); k++) {
 75                                 t=k!=list2.size()-1?(t+list2.get(k)+"\r\n"):t+list2.get(k);
 76                             }
 77                             cell.setCellValue(t);
 78                         }else if(name.equals("count")){
 79                             //请假次数  根据需求增加一些字符串拼接
 80                             cell.setCellValue(map.get(name) != null ? map.get(name).toString()+"次": "");
 81                         }else{
 82                             //普通内容渲染
 83                             cell.setCellValue(map.get(name) != null ? map.get(name).toString(): "");
 84                         }
 85                     }
 86                     cell.setCellStyle(style);
 87                 }
 88             }
 89             
 90             //下面这段是一个固定的文件输出格式
 91             baos = new ByteArrayOutputStream();
 92             wb.write(baos);
 93             HttpServletResponse response = this.getResponse();
 94             response.setContentType("application/vnd.ms-excel;charset=utf-8");
 95             String filename = this.encodeDownloadFilename(fileName,
 96                     getRequest().getHeader("User-Agent")) + ".xls";
 97             response.setHeader("Content-Disposition", "attachment;filename="
 98                     + filename);
 99             bais = new ByteArrayInputStream(baos.toByteArray());
100             int b;
101             while ((b = bais.read()) != -1) {
102                 response.getOutputStream().write(b);
103             }
104             response.getOutputStream().flush();
105             bais.close();
106             baos.close();
107         } catch (Exception e) {
108             e.printStackTrace();
109             this.writeJson("0");
110         }
111     }
112