导出Excel报表

     * 导出Excel报表

     * @param req

     * @param rep

     * @return

     * @throws IOException 

     */

    Public Map emport(HttpServletRequest req,HttpServletResponse rep) throws Exception {

     List list = new ArrayList();        

        rep.reset();

        //写入流

        OutputStream os = rep.getOutputStream();

        //创建工作表

        WritableWorkbook wwb = Workbook.createWorkbook(os);

        try {

            list = testDCJService.getAll(null);        

            //创建时间

            SimpleDateFormat sdf = new SimpleDateFormat("yyyy-MM-dd HH:mm:ss");

            //文件格式

            String fileName = "info_"+sdf.format(new Date())+".xls";

            //

            rep.setContentType("application/x-msdownload");

            //

            rep.setHeader("Content-disposition","attachment;filename="+new String(fileName.getBytes(),"iso-8859-1"));

            //从集合中获取他的长度

            int ncount = list.size();

            // 一次最多写入量

            int maxNum = 50000;

            int times = (ncount + maxNum ) / maxNum;

            //打印

            System.out.println(times);

            for(int i = 0; i < times; i++){

                // 新建一张表

                WritableSheet wsheet = wwb.createSheet("members_" + (i+1),i);

                // 设置表头

                Label label = new Label(0,0,"");

                try {

                    wsheet.addCell(label);

                    label = new Label(0,0,"用户编号");

                    wsheet.addCell(label);

                    label = new Label(1,0,"用户名称");

                    wsheet.addCell(label);

                    label = new Label(2,0,"用户年龄");

                    wsheet.addCell(label);

                    // 读出数据

                    int base = (times-1==i)?ncount%50000:50000;

                    for(int j = 0; j < base; j++){

                            TestDCJ testDcj = list.get(j);    

                            label = new Label(0,(j+1),String.valueOf(testDcj.getId()));

                            wsheet.addCell(label);

                            label = new Label(1,(j+1),testDcj.getUserName());

                            wsheet.addCell(label);

                            label = new Label(2,(j+1),String.valueOf(testDcj.getUserAge()));

                            wsheet.addCell(label);                        

                    }                    

                } catch (RowsExceededException e) {

                    e.printStackTrace();

                } catch (WriteException e) {

                    e.printStackTrace();

                }finally{

                    //执行写入操作

                    wwb.write();

                    //关闭操作

                    wwb.close();

                    os.close();

                }                

            }

        } catch (IOException e) {

            e.printStackTrace();

        }

        return null;

    }