java 读取Blog 字段 输出为Excel

public ActionForward getSchedulerData(ActionMapping mapping, ActionForm form,
   HttpServletRequest request, HttpServletResponse response) throws Exception{
  ServletOutputStream out=response.getOutputStream();
  
  String schedulerid = request.getParameter("schedulerid");
  
  response.reset();
  response.setContentType("application/vnd.ms-excel;charset=GBK");
  //application/vnd.ms-Excel;charset=GBK 表示excel文件类型
  //application/vnd.pdf;charset=GBK 表示pdf文件类型
  //application/msword;charset=GBK
  //setHeader设置打开方式，具体为：inline为在浏览器中打开，attachment单独打开
//  response.setHeader("Content-disposition",
//    "inline;filename=\"" + schedulerid+ ".xls\";");
  byte[] buf=new byte[4096];
  try {
   Blob blob = caManager.getSchedulerData(schedulerid);
   InputStream in = blob.getBinaryStream();
   while (in.read(buf) != -1) {
    out.write(buf);
   }
  } catch (Exception e) {
   log.error(e);
   e.printStackTrace();
  }
  out.flush();
  out.close();
  return null;
 }

----------------------------

public Blob getSchedulerData(String schedulerID) throws Exception {
  String SQL = "select filedata from schedulerfile where schedulerid='"
    + schedulerID + "'";
  System.out.println(SQL);
  List list = bsnsDao.findBySQLForBlob(SQL);
  Blob blob = null;
  if(list != null && list.size()>0) {
   blob = (Blob) list.get(0);
  }
  return blob;
 }

------------list-------------
     rs = stmt.executeQuery(sql);
     if(rs.next()){
      java.sql.Blob value = rs.getBlob("filedata");
      list.add(value);
     }