------------------------------這是異常信息------------------------------

java.lang.NullPointerException

at com.imooc.service.impl.UserServiceImpl.queryUserSimplyInfoById(UserServiceImpl.java:118)

at com.imooc.controller.MyBatisCRUDController.queryUserByIdCustom(MyBatisCRUDController.java:110)

at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)

at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:62)

at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)

------------------------------這是xml配置------------------------------

<mapper namespace="com.imooc.mapper.SysUserMapperCustom" >

<!-- resultType就是不需要配置restmap對應屬性參數，但是需要字段與數據庫字段保持一致? parameterType為傳入參數類型-->

<select id="queryUserSimplyInfoById" resultType="com.imooc.pojo.SysUser"?

parameterType="java.lang.String" >

select * from sys_user where id = #{id,jdbcType=VARCHAR}

</select>

<sql id="columns">id,username</sql>

</mapper>

at java.lang.reflect.Method.invoke(Method.java:498)