public User checkUser(String username,String pwd){
        try{
       pstmt=ct.prepareStatement("select * from usertable where username=? and pwd=?");
       pstmt.setString(1,username);
       pstmt.setString(2,pwd);
          User user=new User();
       ResultSet rs=pstmt.executeQuery();
       
      //  User user=new User();
        while(rs.next()){
            user.setId(rs.getInt(1));
            user.setUsername(rs.getString(2));
            user.setPassword(rs.getString(3));
            return user;
        }
        return null;        }catch(Exception e){
            e.printStackTrace();
            return null;
            
        }
    }调试的时候,执行到ResultSet rs=pstmt.executeQuery();这里就跳到catch里,但我不知道那句哪里错了,也没报错社么的