调用方法时，显示Mapper空指针异常

调用方法时，显示Mapper空指针异常：java.lang.NullPointerException: Cannot invoke "com.light.light_community.dao.UserMapper.selectById(int)" because "this.userMapper" is null

当我在编写完访问数据库方法准备测试时，运行方法显示Mapper空指针异常
错误提示信息是：java.lang.NullPointerException: Cannot invoke "com.light.light_community.dao.UserMapper.selectById(int)" because "this.userMapper" is null

但是我的Mapper是已经注入的

这是我的工程目录

这是我的application.properties 配置文件

这是我的Mapper接口:UserMapper

package com.light.light_community.dao;

import com.light.light_community.entity.User;
import org.apache.ibatis.annotations.Mapper;


@Mapper
public interface UserMapper {

    User selectById(int id);//根据id查询用户
    User selectByName(String name);//根据账号查询用户
    User selectByEmail(String email);//根据邮箱查询用户
    int insertUser(User user);//插入用户数据
    int updateStatus(int id,int status);//根据id更新用户状态
    int updateHeader(int id,String headerUrl);//根据id更新用户头像
    int updatePassword(int id,String password);//根据id更新用户密码

}

这是我的Mapper接口的映射文件：user-mapper.xml

mapper
        PUBLIC "-//mybatis.org//DTD Mapper 3.0//EN"
        "https://mybatis.org/dtd/mybatis-3-mapper.dtd">
<mapper namespace="com.light.light_community.dao.UserMapper">


    <sql id="selectFields">
        id,username,password,salt,email,type,status,activation_code,header_url,create_time
    sql>

    <sql id="insertFields">
        username,password,salt,email,type,status,activation_code,header_url,create_time
    sql>

    <select id="selectById" resultType="User">
        select <include refid="selectFields">include>
        from user
        where id=#{id}
    select>

    <select id="selectByName" resultType="User">
        select <include refid="selectFields">include>
        from user
        where username=#{username}
    select>

    <select id="selectByEmail" resultType="User">
        select <include refid="selectFields">include>
        from user
        where email=#{email}
    select>

    <insert id="insertUser" parameterType="User" keyProperty="id">
        insert into user(<include refid="insertFields">include>)
        values(#{username},#{password},#{salt},#{email},#{type},#{status},#{activationCode},#{headerUrl},#(createTime))
    insert>

    <update id="updateStatus">
        update user
        set status=#{status}
        where id=#{id}
    update>

    <update id="updateHeader">
        update user
        set header_url=#{headerUrl}
        where id=#{id}
    update>

    <update id="updatePassword">
        update password
        ser password=#{password}
        where id=#{id}
    update>


mapper>

这是我的测试程序

    @Autowired
    private UserMapper userMapper;

    @Test
    public void testSelectUser(){
        User user = userMapper.selectById(101);
        System.out.println(user);

    }

首先运行这个测试程序时报的是： org.springframework.beans.factory.NoSuchBeanDefinitionException: No qualifying bean of type 'com.light.light_community.dao.UserMapper' available: expected at least 1 bean which qualifies as autowire candidate. Dependency annotations: {@org.springframework.beans.factory.annotation.Autowired(required=true)}

这个异常，我在网上查资料，看显示是要将@Autowire的改为@Autowired(required=true)，但当我改完之后报的就是Mapper空指针异常了：java.lang.NullPointerException: Cannot invoke "com.light.light_community.dao.UserMapper.selectById(int)" because "this.userMapper" is null

MapperScan

你的resources目录下的路径和java目录下的路径不一致，修改方法：
在resources目录下创建com\light\light_community\dao\UserMapper.目录，将*.xml拷贝到这个目录中。

扫描的包配置了吗

请问你解决了吗，我也遇到了相同的问题