String updateSql = "UPDATEuser SET password = '1234' WHERE username='Gao Shou'";

            long updateRes =stmt.executeUpdate(updateSql);

           System.out.print("UPDATE:" + updateRes);

            //查询数据并输出

            String selectSql = "SELECT *FROM user";

            ResultSet selectRes =stmt.executeQuery(selectSql);

            while (selectRes.next()) {   //循环输出结果集

                String username =selectRes.getString("username");

                String password =selectRes.getString("password");

               System.out.print("\r\n\r\n");

               System.out.print("username:" + username +"password:" + password);

            }

       } catch (Exception e) {

            System.out.print("MYSQLERROR:" + e.getMessage());

       }

   }

}