springboot+mybatis多模块项目maven

Question

下图是我的项目结构。 项目结构

父项目是demo-mybatis 子模块是mybatis-dao,demo-service。 演示-mybatis pom.xml 下面：

4.0.0 pom mybatis-dao demo-service demo-mybatis-app org.springframework.boot spring-boot-starter-parent 2.3.2.RELEASE com.example demo-mybatis 0.0.1-SNAPSHOT demo-mybatis Demo project for Z38008DD86E02F4AF1D7985ECF引导

<properties>
    <java.version>1.8</java.version>
</properties>

<dependencies>
    <dependency>
        <groupId>org.springframework.boot</groupId>
        <artifactId>spring-boot-starter-jdbc</artifactId>
    </dependency>
    <dependency>
        <groupId>org.springframework.boot</groupId>
        <artifactId>spring-boot-starter-web</artifactId>
    </dependency>

    <dependency>
        <groupId>org.springframework.boot</groupId>
        <artifactId>spring-boot-devtools</artifactId>
        <scope>runtime</scope>
        <optional>true</optional>
    </dependency>
    <dependency>
        <groupId>mysql</groupId>
        <artifactId>mysql-connector-java</artifactId>
        <scope>runtime</scope>
    </dependency>
    <dependency>
        <groupId>org.springframework.boot</groupId>
        <artifactId>spring-boot-starter-test</artifactId>
        <scope>test</scope>
        <exclusions>
            <exclusion>
                <groupId>org.junit.vintage</groupId>
                <artifactId>junit-vintage-engine</artifactId>
            </exclusion>
        </exclusions>
    </dependency>
    <dependency>
        <groupId>com.alibaba</groupId>
        <artifactId>druid-spring-boot-starter</artifactId>
        <version>1.1.10</version>
    </dependency>
    <dependency>
        <groupId>org.mybatis.spring.boot</groupId>
        <artifactId>mybatis-spring-boot-starter</artifactId>
        <version>1.3.2</version>
    </dependency>
</dependencies>

mybatis-dao UserMapper.java 接口：```

@Service
public class UserServiceImpl implements UserService {

    @Resource
    private UserMapper userMapper;

    @Override
    public List selectByName(String name) {
        return null;
    }

    @Override
    public int insert(User user) {
        return 0;
    }
}

run application class :
``` @SpringBootApplication
@ComponentScan(basePackages = {"com.example","com.wjs"})
@EnableCaching(proxyTargetClass = true)
@MapperScan(basePackages = {"com.wjs.model.dao"})
public class DemoMybatisAppApplication {

    public static void main(String[] args) {
        SpringApplication.run(DemoMybatisAppApplication.class, args);
    }

}

 @Service public class UserServiceImpl implements UserService { @Resource private UserMapper userMapper; @Override public List selectByName(String name) { return null; } @Override public int insert(User user) { return 0; } }

server.port=8002
spring.datasource.url=jdbc:mysql://localhost:3306/demo?useSSL=false
spring.datasource.driver-class-name=com.mysql.jdbc.Driver
spring.application.name=demo-mybatis
spring.datasource.username=root
spring.datasource.password=root
spring.datasource.type=com.alibaba.druid.pool.DruidDataSource
mybatis.mapper-locations=classpath:mapper/*.xml
mybatis.type-aliases-package=com.wjs.model.entity

application.properties ：

    @Resource
    private UserMapper userMapper;

下面总是异常：我找不到为什么？ 我试试这个：

  nested exception is org.springframework.beans.factory.BeanNotOfRequiredTypeException: Bean named 'userMapper' is expected to be of type 'com.wjs.model.dao.UserMapper' but was actually of type 'com.sun.proxy.$Proxy55'

问题是：

    @Autowired
    private UserMapper userMapper;

和

 No qualifying bean of type 'com.wjs.model.dao.UserMapper' available: expected at least 1 bean which qualifies as autowire candidate. Dependency annotations: {@org.springframework.beans.factory.annotation.Autowired(required=true)}

问题是：

 No qualifying bean of type 'com.wjs.model.dao.UserMapper' available: expected at least 1 bean which qualifies as autowire candidate. Dependency annotations: {@org.springframework.beans.factory.annotation.Autowired(required=true)}

我疯了

Answer 1

@Mapper 公共接口 UserMapper

描述：

bean 'userMapper' 不能作为 'com.example.mapper.UserMapper' 注入，因为它是一个 JDK 动态代理，它实现：

行动：

考虑将 bean 作为其接口之一注入或通过在 @EnableAsync 和/或 @EnableCaching 上设置 proxyTargetClass=true 来强制使用基于 CGLib 的代理。