@Test    public void test3(){        Connection conn = null;        PreparedStatement preparedStatement = null;        ResultSet resultSet = null;        String sql = "insert into student(name,password) values(?,?)";        try {            conn = Methods.getConnection();            //使用重载的prepareStatement(sql,flag)来生成prepareStatement对象            preparedStatement = conn.prepareStatement(sql,Statement.RETURN_GENERATED_KEYS);            preparedStatement.setString(1,"yang5");            preparedStatement.setString(2,"1235");            preparedStatement.executeUpdate();            //通过getGenerateKeys获取包含了新生成主键的ResultSet对象            //在ResultSet中只有一列GENERATED_KEY,用于存放新生成的主键值。            resultSet = preparedStatement.getGeneratedKeys();            if(resultSet.next()){                System.out.println(resultSet.getObject(1));            }            ResultSetMetaData rsmd = resultSet.getMetaData();            for (int i = 0; i < rsmd.getColumnCount(); i++) {                System.out.println(rsmd.getCatalogName(i+1));            }        } catch (Exception e) {            e.printStackTrace();        } finally {            Methods.release(preparedStatement,conn,resultSet);        }