【异常】The dependencies of some of the beans in the application context form a cycle

一、异常出现场景以及异常信息

场景：SpringBoot中自定义DataSource数据源

异常信息：

-- ::30.807 ERROR  --- [           main] o.s.b.d.LoggingFailureAnalysisReporter   : 

***************************
APPLICATION FAILED TO START
***************************

Description:

The dependencies of some of the beans in the application context form a cycle:

   userServiceImpl (field com.zbq.springbootdemo.dao.UserDao com.zbq.springbootdemo.service.UserServiceImpl.userDao)
      ↓
   userDao defined in file [/Users/zhangboqing/Software/MyGithub/spring-boot-demo/target/classes/com/zbq/springbootdemo/dao/UserDao.class]
      ↓
   sqlSessionFactory defined in class path resource [org/mybatis/spring/boot/autoconfigure/MybatisAutoConfiguration.class]
┌─────┐
|  dynamicDataSource defined in class path resource [com/zbq/springbootdemo/config/multidatasource/DataSourceConfig.class]
↑     ↓
|  primary defined in class path resource [com/zbq/springbootdemo/config/multidatasource/DataSourceConfig.class]
↑     ↓
|  org.springframework.boot.autoconfigure.jdbc.DataSourceInitializerInvoker

二、解决方案

排除Spring Boot数据源自动配置类

// 自定义数据源一定要排除SpringBoot自动配置数据源，不然会出现循环引用的问题，The dependencies of some of the beans in the application context form a cycle
@EnableAutoConfiguration(exclude = {DataSourceAutoConfiguration.class})