SpringBoot模块化开发之模块循环依赖问题

ゝ一世哀愁。 2023-10-08 16:26 39阅读 0赞

## 项目场景： ##

**项目结构：**启动类模块：certificate\_service（pom.xml中添加了通用模块和考试模块作为依赖）、通用模块：certificate\_service\_commons、考试模块：certificate\_service\_exam（pom.xml中导入了通用模块作为依赖）。

**业务需求：**考试模块需要调用启动类主模块的userMapper的函数获取数据库中的用户数据。

![358434c316644896b61b3dd2a13aaa90.png][]

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## 实战思路一（失败）： ##

起初想着在考试模块的pom.xml中添加主模块作为依赖不就可以了吗，试过之后会发现在编译的时候，会产生循环依赖的错误Error:java: Annotation processing is not supported for module cycles. Please ensure that all modules from cycle \[certificate\_service,certificate\_service\_exam\] are excluded from annotation processing``

>     
>     <dependency>
>         <groupId>com.luntek</groupId>
>         <artifactId>certificate_service</artifactId>
>         <version>0.0.1-SNAPSHOT</version>
>     </dependency>

![3faf208f233040d2b1ef5da499b77f92.png][]

--------------------

## 实战思路二（成功）： ##

换个思路：将UserMapper文件放到通用模块commons中，这样启动类主模块可以用到，考试模块也可以用到，达到解决问题的目的。

**步骤一：**将UserMapper文件从主模块移动到通用模块中去

![c721f4dfa74441a9a465c388e7d34d07.png][]

**步骤二：**启动类中的@MapperScan注解中添加通用模块Mapper文件路径注入到容器以便扫描加载使用。

package com.luntek.certificate;
    
    import org.mybatis.spring.annotation.MapperScan;
    import org.springframework.boot.SpringApplication;
    import org.springframework.boot.autoconfigure.SpringBootApplication;
    import org.springframework.context.annotation.ComponentScan;
    import org.springframework.scheduling.annotation.EnableScheduling;
    import org.springframework.transaction.annotation.EnableTransactionManagement;
    import springfox.documentation.swagger2.annotations.EnableSwagger2;
    
    @EnableSwagger2
    @EnableScheduling
    @EnableTransactionManagement
    @ComponentScan(basePackages = {"com.luntek"})
    @MapperScan(basePackages = {"com.luntek.certificate.mapper","com.luntek.commons.mapper",
            "com.luntek.exam.mapper"})
    @SpringBootApplication
    public class CertificateServiceApplication {
    
        public static void main(String[] args) {
            SpringApplication.run(CertificateServiceApplication.class, args);
        }
    
    }

**步骤三：**考试模块使用userMapper时，依赖注入通用模块下的UserMapper即可使用了

import com.luntek.commons.mapper.UserMapper;
    
    public class UseUserMapperServiceImpl implements UserUserMapperService{
    
        @Autowired
        private UserMapper userMapper;
    
        public String useUserMapperMethod(String Param){
            String userId = userMapper.getUserIdByParam(Param);
            return userId;
        }
    
    }

**步骤四：**Rebuild project项目重新编译一下，然后启动项目

![acbcdeab3a36438ea765bf6906c8a0a0.png][]

结束：小小问题，记录一下，输出巩固一下

##  ##

[358434c316644896b61b3dd2a13aaa90.png]: https://img-blog.csdnimg.cn/358434c316644896b61b3dd2a13aaa90.png
[3faf208f233040d2b1ef5da499b77f92.png]: https://img-blog.csdnimg.cn/3faf208f233040d2b1ef5da499b77f92.png
[c721f4dfa74441a9a465c388e7d34d07.png]: https://img-blog.csdnimg.cn/c721f4dfa74441a9a465c388e7d34d07.png
[acbcdeab3a36438ea765bf6906c8a0a0.png]: https://img-blog.csdnimg.cn/acbcdeab3a36438ea765bf6906c8a0a0.png