Spring循环依赖-spring源码详解（四）

 public static void loadBeanDefinitions() {
        RootBeanDefinition rootBeanDefinitionA = new RootBeanDefinition(InstanceA.class);
        RootBeanDefinition rootBeanDefinitionB = new RootBeanDefinition(InstanceB.class);
        beanDefinitionMap.put("instanceA", rootBeanDefinitionA);
        beanDefinitionMap.put("instanceB", rootBeanDefinitionB);
    }
 
@Component
public class InstanceA {
    @Autowired
    private InstanceB instanceB;
 
    public InstanceB getInstanceB() {
        return instanceB;
    }
 
    public void setInstanceB(InstanceB instanceB) {
        this.instanceB = instanceB;
    }
 
    public InstanceA(InstanceB instanceB) {
        this.instanceB = instanceB;
    }
 
    public InstanceA() {
        System.out.println("实例化A");
    }
}