Spring循環依賴報錯Bean with name '**' has been injected into other beans [**] in its raw version as part

異常詳情

Bean with name ‘commonService’ has been injected into other beans [] in its raw version as part of a circular reference, but has eventually been wrapped. This means that said other beans do not use the final version of the bean. This is often the result of over-eager type matching - consider using ‘getBeanNamesOfType’ with the ‘allowEagerInit’ flag turned off, for example.**

springboot循環依賴解決

1. 循環依賴是什么？

Bean A 依賴 B，Bean B 依賴 A這種情況下出現循環依賴。
Bean A → Bean B → Bean A
更復雜的間接依賴造成的循環依賴如下。
Bean A → Bean B → Bean C → Bean D → Bean E → Bean A

2. 循環依賴會產生什么結果？

當Spring正在加載所有Bean時，Spring嘗試以能正常創建Bean的順序去創建Bean。
例如，有如下依賴:
Bean A → Bean B → Bean C
Spring先創建beanC，接着創建bean B（將C注入B中)，最后創建bean A(將B注入A中)。

但當存在循環依賴時，Spring將無法決定先創建哪個bean。這種情況下，Spring將產生異常BeanCurrentlyInCreationException。

3.普通注入之間的循環依賴

比如：我現在有一個ServiceA需要調用ServiceB的方法，那么ServiceA就依賴於ServiceB，那在ServiceB中再調用ServiceA的方法，就形成了循環依賴。Spring在初始化bean的時候就不知道先初始化哪個，bean就會報錯。

public class ClassA { 
   @Autowired
   ClassB classB; 
}

public class ClassB { 
    @Autowired 
    ClassA classA 
}

解決辦法:

如何解決循環依賴，最好的方法是重構代碼，進行解耦，如果沒有時間重構，可以使用下面的方法：

（1）在你的配置文件中，在互相依賴的兩個bean的任意一個加上lazy-init屬性

<bean id="ServiceDependent1" class="org.xyz.ServiceDependent1" lazy-init="true">
<constructor-arg ref="Service"/>
</bean>
<bean id="ServiceDependent2" class="org.xyz.ServiceDependent2" lazy-init="true">
<constructor-arg ref="Service"/>
</bean>   

（2）在你注入bean時，在互相依賴的兩個bean上加上@Lazy注解也可以

    @Autowired
    @Lazy
    private ClassA classA;
    @Autowired
    @Lazy
    private ClassB classB;

構造器注入循環依賴實例

首先定義兩個相互通過構造器注入依賴的bean。

@Componentpublic
    class CircularDependencyA {
        private CircularDependencyB circB;

        @Autowired
        public CircularDependencyA(CircularDependencyB circB) {
            this.circB = circB;
        }
    }

    @Componentpublic
    class CircularDependencyB {
        private CircularDependencyA circA;

        @Autowired
        public CircularDependencyB(CircularDependencyA circA) {
            this.circA = circA;
        }
    }

    @Configuration
    @ComponentScan(basePackages = {"com.baeldung.circulardependency"})
    public class TestConfig {
    }

@RunWith(SpringJUnit4ClassRunner.class)
    @ContextConfiguration(classes = {TestConfig.class})
    public class CircularDependencyTest {
        @Test
        public void givenCircularDependency_whenConstructorInjection_thenItFails() {               
           // Empty test; we just want the context to load
    }
}

運行方法
givenCircularDependency_whenConstructorInjection_thenItFails
將會產生異常：BeanCurrentlyInCreationException: Error creating bean with name ‘circularDependencyA’:
Requested bean is currently in creation: Is there an unresolvable circular reference?

如何解決

（1）重新設計

重新設計結構，消除循環依賴。

（2）使用注解 @Lazy

一種最簡單的消除循環依賴的方式是通過延遲加載。在注入依賴時，先注入代理對象，當首次使用時再創建對象完成注入。

    @Componentpublic
    class CircularDependencyA {
        private CircularDependencyB circB;

        @Autowired
        public CircularDependencyA(@Lazy CircularDependencyB circB) {
            this.circB = circB;
        }
    }

使用@Lazy后，運行代碼，可以看到異常消除。
（3）使用Setter/Field注入
Spring文檔建議的一種方式是使用setter注入。當依賴最終被使用時才進行注入。對前文的樣例代碼少做修改，來觀察測試效果。

    @Componentpublic
    class CircularDependencyA {
        private CircularDependencyB circB;

        @Autowired
        public void setCircB(CircularDependencyB circB) {
            this.circB = circB;
        }

        public CircularDependencyB getCircB() {
            return circB;
        }
    }

    @Componentpublic
    class CircularDependencyB {
        private CircularDependencyA circA;
        private String message = "Hi!";

        @Autowired
        public void setCircA(CircularDependencyA circA) {
            this.circA = circA;
        }

        public String getMessage() {
            return message;
        }
    }

    @RunWith(SpringJUnit4ClassRunner.class)
    @ContextConfiguration(classes = {TestConfig.class})
    public class CircularDependencyTest {
        @Autowired
        ApplicationContext context;

        @Bean
        public CircularDependencyA getCircularDependencyA() {
            return new CircularDependencyA();
        }

        @Bean
        public CircularDependencyB getCircularDependencyB() {
            return new CircularDependencyB();
        }

        @Test
        public void givenCircularDependency_whenSetterInjection_thenItWorks() {
            CircularDependencyA circA = context.getBean(CircularDependencyA.class);
            Assert.assertEquals("Hi!", circA.getCircB().getMessage());
        }
    }

（4） 使用@PostConstruct

    @Componentpublic
    class CircularDependencyA {
        @Autowired
        private CircularDependencyB circB;

        @PostConstruct
        public void init() {
            circB.setCircA(this);
        }

        public CircularDependencyB getCircB() {
            return circB;
        }
    }

    @Componentpublic
    class CircularDependencyB {
        private CircularDependencyA circA;
        private String message = "Hi!";

        public void setCircA(CircularDependencyA circA) {
            this.circA = circA;
        }

        public String getMessage() {
            return message;
        }
    }

（5）實現ApplicationContextAware與InitializingBean

    @Componentpublic
    class CircularDependencyA implements ApplicationContextAware, InitializingBean {
        private CircularDependencyB circB;
        private ApplicationContext context;

        public CircularDependencyB getCircB() {
            return circB;
        }

        @Override
        public void afterPropertiesSet() throws Exception {
            circB = context.getBean(CircularDependencyB.class);
        }

        @Override
        public void setApplicationContext(final ApplicationContext ctx) throws BeansException {
            context = ctx;
        }
    }

    @Componentpublic
    class CircularDependencyB {
        private CircularDependencyA circA;
        private String message = "Hi!";

        @Autowired
        public void setCircA(CircularDependencyA circA) {
            this.circA = circA;
        }

        public String getMessage() {
            return message;
        }
    }