@Component
public class ServiceA {
    private final ServiceB serviceB;
    
    @Autowired
    public ServiceA(ServiceB serviceB) { // 構(gòu)造器注入
        this.serviceB = serviceB;
    }
}
 
@Component
public class ServiceB {
    private final ServiceA serviceA;
    
    @Autowired
    public ServiceB(ServiceA serviceA) { // 構(gòu)造器注入
        this.serviceA = serviceA;
    }
}

@Autowired
  public ServiceA(@Lazy ServiceB serviceB) { 
      this.serviceB = serviceB;
  }

@Scope("prototype")
@Component
public class PrototypeA {
    @Autowired private PrototypeB b;
}
 
@Scope("prototype")
@Component
public class PrototypeB {
    @Autowired private PrototypeA a;
}

@Service
public class AsyncServiceA {
    @Autowired private AsyncServiceB serviceB;
    
    @Async
    public void asyncMethod() { /* ... */ }
}
 
@Service
public class AsyncServiceB {
    @Autowired private AsyncServiceA serviceA;
}

BeanCreationException: Error creating bean with name 'asyncServiceA': 
Bean with name 'asyncServiceA' has been injected into other beans [...] in their raw version as part of a circular reference.

@Async
public interface AsyncService {
    void asyncMethod();
}
 
@Service
public class AsyncServiceImpl implements AsyncService { /* ... */ }

@Autowired @Lazy private AsyncServiceA serviceA;

@Configuration
public class ConfigA {
    @Autowired private ConfigB configB;
}
 
@Configuration
public class ConfigB {
    @Autowired private ConfigA configA;
}

@Configuration
@DependsOn("configB")
public class ConfigA { /* ... */ }

@Component
public class CustomProcessor implements BeanPostProcessor {
    @Autowired private ServiceX x; // 依賴(lài)其他Bean
}

private ObjectProvider<ServiceX> xProvider;
  
  public Object postProcessBeforeInitialization(Object bean, String beanName) {
      ServiceX x = xProvider.getIfAvailable();
      // ...
  }