如下代码，ComponentA类注入ComponentB类，ComponentB类注入ComponentA类，就会发生循环依赖的问题，在2.6.0之前，spring会自动处理循环依赖的问题

 

import org.springframework.stereotype.Service;

 

import javax.annotation.Resource;

 

@Service

 

public class ComponentA {

 

    @Resource

 

    private ComponentB componentB;

 

}

 

import org.springframework.stereotype.Service;

 

import javax.annotation.Resource;

 

@Service

 

public class ComponentB {

 

    @Resource

 

    private ComponentA componentA;

 

}

 

现在，2.6.0 这个版本已经默认禁止 Bean 之间的循环引用，如果存在循环引用就会启动失败报错：

 

***************************

 

APPLICATION FAILED TO START

 

***************************

 

Description:

 

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

 

┌─────┐

 

|  componentA

 

↑     ↓

 

|  componentB

 

└─────┘

 

Action:

 

Relying upon circular references is discouraged and they are prohibited by default. Update your application to remove the dependency cycle between beans. As a last resort, it may be possible to break the cycle automatically by setting spring.main.allow-circular-references to true.

 

处理方案一：

 

 整改业务，清理掉所有存在循环引用的 Bean

 

处理方案二：

 

spring:

 

  main:

 

    allow-circular-references: true

 

处理方案三：

 

import org.springframework.boot.SpringApplication;

 

import org.springframework.boot.autoconfigure.SpringBootApplication;

 

@SpringBootApplication

 

public class SpringDemoApplication {

 

    public static void main（String[] args） {

 

        SpringApplication application = new SpringApplication（SpringDemoApplication.class）;

 

        application.setAllowCircularReferences（Boolean.TRUE）;

 

        application.run（args）;

 

    }

 

}