java操作Excel之POI（4）利用POI实现数据的批量导出

后台导出方法：

 /**
 *    后台导出方法
 *    利用POI实现数据的批量导出
 */
 public String export() throws Exception{
     Connection con = null;
     try{
         con = dbUtil.getCon();
         Workbook wb = new HSSFWorkbook();
         String headers[] = {"编号", "姓名", "电话", "Email", "QQ"};
         ResultSet rs = userDao.userList(con, null);
         ExcelUtil.fillExcelData(rs, wb, headers);

         //把wb以流的形式输出
         ResponseUtil.export(ServletActionContext.getResponse(), wb, "导出Excel.xls");
     }catch(Exception e){
         e.printStackTrace();
     }finally{
         try{
             dbUtil.closeCon(con);
             dbUtil.closeRs(rs);
         }catch(Exception e){
             e.printStackTrace();
         }
     }

     return null;
 }

处理excel的Util：

 /**
 *    处理Excel的util
 */
 public class ExcelUtil{

     public static void fillExcelData(ResultSet rs, Workbook wb, String[] headers) throws Exception{
         int rowIndex = 0;
         Sheet sheet = wb.createSheet();
         Row row = sheet.createRow(rowIndex++);
         for(int i=0; i<headers.length; i++){
             row.createCell(i).setCellValue(headers[i]);
         }

         //这里假设的是头的列数和数据的列数是一样的
         while(rs.next()){
             row = sheet.createRow(rowIndex++);
             for(int i=0; i<headers.length; i++){
                 row.createCell(i).setCellValue(rs.getObject(i+1).toString());
             }
         }
     }
 }

ResponseUtil以流的形式导出Workbook:

 /**
 *    ResponseUtil相应util
 */
 public class ResponseUtil{
     public static void write(HttpServletResponse response, Object o) throws Exception{
         response.setContentType("text/html;charset=utf-8");
         PrintWriter pw = response.getWriter();
         pw.print(o.toString());
         pw.flush();
         pw.close();
     }

     /**
     *导出Excel
     * fileName: 导出的文件名
     */
     public static void export(HttpServletResponse response, Workbook wb, String fileName) throws Exception{
         response.setHeader("Content-Disposition", "attachment;filename="
             +new String(fileName.getBytes("utf-8"), "iso8859-1"));
         response.setContentType("application/ynd.ms-excel;charset=UTF-8");
         OutputStream out = response.getOutputStream();
         wb.write(out);
         out.flush();
         out.close();
     }
 }

导出的Excel: