显示BlobT图的问题,好心的高手来看看吧.不报错,也不显示

Question

package dss.action;import org.apache.struts.action.*;
import javax.servlet.http.*;
import java.io.*;
import dss.framework.operateblob;public class showBlobAction extends Action {
  public ActionForward execute(ActionMapping actionMapping, ActionForm actionForm,
                               HttpServletRequest request, HttpServletResponse response)
  {          operateblob myQuery=new operateblob();
          String userno=request.getParameter("impo_user_no");
          int nViewId=Integer.parseInt(request.getParameter("viewid"));
          String sql="select graph from dssf_user_part_info where user_no='"+userno+"'";          
          java.sql.Blob myBlob=myQuery.getBlob(sql,1);          if(myBlob==null){
            myQuery.CloseConnect();
            return null;
          }
          InputStream ins=null;
          OutputStream outStream=null;
          try{
             ins= myBlob.getBinaryStream();
             response.setContentType("image/jpeg");
             outStream=response.getOutputStream();
             byte[] bytes = new byte[1024];
             int len = 0;
             while ((len=ins.read(bytes))!=-1) {
               outStream.write(bytes,0,len);
             }             ins.close();
             outStream.close();
             outStream = null;
          }
          catch(Exception ex){}
          finally{ myQuery.CloseConnect();}
          return null;
  }}后台也不报错,前端也不显示,郁闷呀

Answer 1

java.sql.Blob myBlob=myQuery.getBlob(sql,1);
//应该是执行SQL语句，返回Blob          if(myBlob==null){
            myQuery.CloseConnect();
            //这里调试一下吧，可能是myBlob没出结果
            return null;
          }