为什么相片无法显示..????急救

/*读取照片
     * 
     */
    public HashMap searchStudPho(String stud_code) throws Exception {
        HashMap hm = new HashMap();
        int ks_h=Integer.parseInt(stud_code);
        String sql = "select ks_h,xp from ks_xp where ks_h="+ks_h+"";
        try {
          Linkdata db = new Linkdata();
          conn = db.getConnection();
          ps = conn.prepareStatement(sql);
          //ps.setInt(1, ks_h);    
          rs = ps.executeQuery();
          //ks_h=rs.getInt(ks_h);
          //Integer ks=new Integer(ks_h); 
          try{
              if(rs.next()){
                  hm.put("stud_code", stud_code);
                 InputStream ins=rs.getBinaryStream("xp");
                  hm.put("xp", ins);
          }
          else {
            hm = null;
          }
            }catch(SQLException el){
                el.printStackTrace();
            }
            
        }catch (Exception e) {
          hm = null;
          throw new Exception("SearchStudPho Error:---" + e);
        } //外部关闭
        finally {
            if (rs != null) {
                try {
                  rs.close();
                  rs = null;
                }
                catch (SQLException e) {
                  e.printStackTrace();
                }
              }
              if (ps != null) {
                try {
                  ps.close();
                  ps = null;
                }
                catch (SQLException e) {
                  e.printStackTrace();
                }
              }
              if (conn != null||!conn.isClosed()) {
                try {
                  conn.close();
                  conn = null;
                }
                catch (SQLException e) {
                  e.printStackTrace();
                }
              }
            }
        return hm;
      }/*servlet读取相片*/
public void doGet(HttpServletRequest request, HttpServletResponse response)
    throws ServletException, IOException {response.setContentType("text/html");
//PrintWriter out = response.getWriter();
studentInfo ps = new studentInfo();
HashMap hm = new HashMap();
System.out.println("here1");
//输入img字段内容到in
try {
  
  String stud_code = request.getParameter("stud_code");
  hm = ps.searchStudPho(stud_code);
  InputStream in = null;
  System.out.println("here2");
  if (hm != null) { System.out.println("here3");
    byte[] b = new byte[1024];
    int len = 0;
    in = (InputStream) hm.get("xp");System.out.println("here43333");
    len = in.read(b);System.out.println("here55555555");
    response.reset();
    response.setContentType("image/jpeg"); 
    while ( len  != -1) {
      response.getOutputStream().write(b, 0, len);
    }
    if(in!=null){  in.close(); } 
  }
  else {
    byte[] b = new byte[1024];
    int len = 0;
    String path = request.getSession().getServletContext().getRealPath("/") +
    "\\images\\nophoto.jpg";
    in = new FileInputStream(path);
    response.reset();
    response.setContentType("image/jpeg");
    len = in.read(b);
    while ( len  != -1) {
        response.getOutputStream().flush();
         response.getOutputStream().write(b, 0, len);
    }
  }
  if(in!=null){
      in.close(); 
  } 
}
catch (Exception de) {
  System.out.println("photo show error:--" + de);
}
}