idea Could not autowire. No beans of type found

[sfbayscott2008]

今天在学习spring boot的似乎还遇到这个，不知道哪里出错了，希望各位大神指教，谢谢


Could not autowire. No beans of 'AppMessageMapper' type found. less... (Ctrl+F1)
Checks autowiring problems in a bean class.

***************************************************************************************
java.lang.NullPointerException: null
at com.example.mybatis.test.APPMessageController.getAllMessage(APPMessageController.java:30) ~[classes/:na]
at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method) ~[na:1.8.0_181]
at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:62) ~[na:1.8.0_181]
at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43) ~[na:1.8.0_181]
at java.lang.reflect.Method.invoke(Method.java:498) ~[na:1.8.0_181]
at org.springframework.web.method.support.InvocableHandlerMethod.doInvoke(InvocableHandlerMethod.java:190) ~[spring-web-5.1.8.RELEASE.jar:5.1.8.RELEASE]

*************************************************************************
@Component
public class AppMessageService implements IAppMessageService {

@Autowired
private AppMessageMapper appMessageMapper;

[tongqing9205]

你是不是应该在Controller里面注入mapper啊

[朝霞清辉]

AppMessageMapper这个没找到啊，你是怎么配置这个mapper的，检查一下吧

[sfbayscott2008]

#mysql
spring.datasource.url=jdbc:mysql://localhost:3306/test?serverTimezone=GMT%2B8
spring.datasource.username=root
spring.datasource.password=123456
spring.datasource.driver-class-name=com.mysql.cj.jdbc.Driver

#mybatis
mybatis.mapper-locations=classpath:/mappers/*Mapper.xml
mybatis.type-aliases-package=com.example.mybatis.test

[sfbayscott2008]

<?xml version="1.0" encoding="UTF-8" ?>
<!DOCTYPE mapper PUBLIC "-//mybatis.org//DTD Mapper 3.0//EN" "http://mybatis.org/dtd/mybatis-3-mapper.dtd" >
<mapper namespace="com.example.mybatis.test.AppMessageMapper" >

<resultMap id="BaseResultMap" type="com.example.mybatis.test.AppMessage" >
<id column="id" property="id" jdbcType="VARCHAR" />
<result column="message" property="message" jdbcType="VARCHAR" />
<result column="senddate" property="senddate" jdbcType="TIMESTAMP" />
</resultMap>

<sql id="Base_Column_List" >
id, message, senddate
</sql>
<select id="selectByPrimaryKey" resultMap="BaseResultMap" parameterType="java.lang.String" >
select
<include refid="Base_Column_List" />
from appuser_message
where id = #{id,jdbcType=VARCHAR}
</select>
<delete id="deleteByPrimaryKey" parameterType="java.lang.String" >
delete from appuser_message
where id = #{id,jdbcType=VARCHAR}
</delete>
<insert id="insert" parameterType="com.example.mybatis.test.AppMessage" >
insert into appuser_message (id, message, senddate
)
values (#{id,jdbcType=VARCHAR}, #{message,jdbcType=VARCHAR}, #{senddate,jdbcType=TIMESTAMP}
)
</insert>
<insert id="insertSelective" parameterType="com.example.mybatis.test.AppMessage" >
insert into appuser_message
<trim prefix="(" suffix=")" suffixOverrides="," >
<if test="id != null" >
id,
</if>
<if test="message != null" >
message,
</if>
<if test="senddate != null" >
senddate,
</if>
</trim>
<trim prefix="values (" suffix=")" suffixOverrides="," >
<if test="id != null" >
#{id,jdbcType=VARCHAR},
</if>
<if test="message != null" >
#{message,jdbcType=VARCHAR},
</if>
<if test="senddate != null" >
#{senddate,jdbcType=TIMESTAMP},
</if>
</trim>
</insert>
<update id="updateByPrimaryKeySelective" parameterType="com.example.mybatis.test.AppMessage" >
update appuser_message
<set >
<if test="message != null" >
message = #{message,jdbcType=VARCHAR},
</if>
<if test="senddate != null" >
senddate = #{senddate,jdbcType=TIMESTAMP},
</if>
</set>
where id = #{id,jdbcType=VARCHAR}
</update>
<update id="updateByPrimaryKey" parameterType="com.example.mybatis.test.AppMessage" >
update appuser_message
set message = #{message,jdbcType=VARCHAR},
senddate = #{senddate,jdbcType=TIMESTAMP}
where id = #{id,jdbcType=VARCHAR}
</update>

<select id="selectAll" resultMap="BaseResultMap">
select
id, message, senddate
from appuser_message
order by senddate asc
</select>

<select id="getMessById" resultMap="BaseResultMap" parameterType="java.lang.String">
select
id, message, senddate
from
appuser_message
where id = #{id,jdbcType=VARCHAR}
order by senddate asc
</select>

</mapper>

[「已注销」]

java.lang.NullPointerException: null at com.example.mybatis.test.APPMessageController.getAllMessage(APPMessageController.java:30) APPMessageController 30行这里有空指针

[朝霞清辉]

昨天看错了，不确定是不是那个mapper注入失败。controller第二十行是什么，看报错是这里的问题

[cwmlow]

看代码 看看controller层@Autowired注解是否装配的是AppMessageService，然后看看dao层的mapper文件有没有加@mapper注解跟mapper.xml做映射