public class BeanA {
private BeanB beanB;
public BeanB getBeanB() {
 return beanB;
}
public void setBeanB(BeanB beanB) {
 this.beanB = beanB;
}
}

public class BeanB {
private BeanA beanA;
public BeanA getBeanA() {
 return beanA;
}
public void setBeanA(BeanA beanA) {
 this.beanA = beanA;
}
}

<bean id="beanA" class="com.alibaba.test.circle.BeanA">
<property name="beanB">
 <ref bean="beanB" />
</property>
</bean>

<bean id="beanB" class="com.alibaba.test.circle.BeanB">
<property name="beanA">
 <ref bean="beanA" />
</property>
</bean>

Object sharedInstance = getSingleton(beanName);//getSingleton(beanName,true);
if (sharedInstance != null && args == null) {
if (logger.isDebugEnabled()) {
 if (isSingletonCurrentlyInCreation(beanName)) {
 logger.debug("Returning eagerly cached instance of singleton bean '" + beanName +
 "' that is not fully initialized yet - a consequence of a circular reference");
 }
 else {
 logger.debug("Returning cached instance of singleton bean '" + beanName + "'");
 }
}
 // 如果是普通bean直接返回，工廠bean則返回sharedInstance.getObject();
bean = getObjectForBeanInstance(sharedInstance, name, beanName, null);
}

protected Object getSingleton(String beanName, boolean allowEarlyReference) {
 Object singletonObject = this.singletonObjects.get(beanName);
 if (singletonObject == null) {
 synchronized (this.singletonObjects) {
 singletonObject = this.earlySingletonObjects.get(beanName);
 if (singletonObject == null && allowEarlyReference) {
 ObjectFactory singletonFactory = (ObjectFactory) this.singletonFactories.get(beanName);
 if (singletonFactory != null) {
  singletonObject = singletonFactory.getObject();
  this.earlySingletonObjects.put(beanName, singletonObject);
  this.singletonFactories.remove(beanName);
 }
 }
 }
 }
 return (singletonObject != NULL_OBJECT ? singletonObject : null);
}

boolean earlySingletonExposure = (mbd.isSingleton() && this.allowCircularReferences &&
isSingletonCurrentlyInCreation(beanName));

if (earlySingletonExposure) {
if (logger.isDebugEnabled()) {
 logger.debug("Eagerly caching bean '" + beanName +
 "' to allow for resolving potential circular references");
}
addSingletonFactory(beanName, new ObjectFactory() {
 public Object getObject() throws BeansException {
 return getEarlyBeanReference(beanName, mbd, bean);
 }
});
}

protected void addSingletonFactory(String beanName, ObjectFactory singletonFactory) {
Assert.notNull(singletonFactory, "Singleton factory must not be null");
synchronized (this.singletonObjects) {
 if (!this.singletonObjects.containsKey(beanName)) {
 this.singletonFactories.put(beanName, singletonFactory);
 this.earlySingletonObjects.remove(beanName);
 this.registeredSingletons.add(beanName);
 }
}
}

public class TestCircle2 {
private final static ClassPathXmlApplicationContext moduleContext;
private static Test test;
static {
 moduleContext = new ClassPathXmlApplicationContext(new String[]{"beans-circile.xml"});
 moduleContext.setAllowCircularReferences(false);
 test = (Test) moduleContext.getBean("test");
}
public static void main(String[] args) {

 System.out.println(test.name);
}
}

public ClassPathXmlApplicationContext(String[] configLocations) throws BeansException {
this(configLocations, true, null);
}

public ClassPathXmlApplicationContext(String[] configLocations, boolean refresh, ApplicationContext parent)
 throws BeansException {
super(parent);
setConfigLocations(configLocations);
if (refresh) {
 refresh();
}
}

public ClassPathXmlApplicationContext(String[] configLocations, boolean refresh, ApplicationContext parent)
 throws BeansException {
super(parent);
setConfigLocations(configLocations);
if (refresh) {
 refresh();
}
}

protected final void refreshBeanFactory() throws BeansException {
if (hasBeanFactory()) {
 destroyBeans();
 closeBeanFactory();
}
try {
 // 創(chuàng)建bean工廠
 DefaultListableBeanFactory beanFactory = createBeanFactory();
 //定制bean工廠屬性
 customizeBeanFactory(beanFactory);
 loadBeanDefinitions(beanFactory);
 synchronized (this.beanFactoryMonitor) {
 this.beanFactory = beanFactory;
 }
}
catch (IOException ex) {
 throw new ApplicationContextException(
 "I/O error parsing XML document for application context [" + getDisplayName() + "]", ex);
}
}

protected void customizeBeanFactory(DefaultListableBeanFactory beanFactory) {
if (this.allowBeanDefinitionOverriding != null) {
 beanFactory.setAllowBeanDefinitionOverriding(this.allowBeanDefinitionOverriding.booleanValue());
}
if (this.allowCircularReferences != null) {
 beanFactory.setAllowCircularReferences(this.allowCircularReferences.booleanValue());
}
}

public class TestCircle {
private final static ClassPathXmlApplicationContext moduleContext;
private static Test test;
static {
 //初始化容器上下文，但是不刷新容器
 moduleContext = new ClassPathXmlApplicationContext(new String[]{"beans-circile.xml"},false);
 moduleContext.setAllowCircularReferences(false);
 //刷新容器
 moduleContext.refresh();
 test = (Test) moduleContext.getBean("test");
}
public static void main(String[] args) {
 System.out.println(test.name);
}
}

public class MyFactoryBean implements FactoryBean,InitializingBean{
private String name;
private Test test;
public String getName() {
 return name;
}
public void setName(String name) {
 this.name = name;
}
public DependentBean getDepentBean() {
 return depentBean;
}
public void setDepentBean(DependentBean depentBean) {
 this.depentBean = depentBean;
}
private DependentBean depentBean;
public Object getObject() throws Exception {

 return test;
}
public Class getObjectType() {
 // TODO Auto-generated method stub
 return Test.class;
}
public boolean isSingleton() {
 // TODO Auto-generated method stub
 return true;
}
public void afterPropertiesSet() throws Exception {
  System.out.println("name:" + this.name);
  test = new Test();
  test.name = depentBean.doSomething() + this.name;
}
}

public class Test {
public String name;
}

public class DependentBean {
public String doSomething(){
 return "hello:";
}
@Autowired
private Test test;
}

<bean id="test" class="com.alibaba.test.circle.MyFactoryBean">
<property name="depentBean">
 <bean class="com.alibaba.test.circle.DependentBean"></bean>
</property>
<property name="name" value="zlx"></property>
</bean>

public class TestCircle2 {
private final static ClassPathXmlApplicationContext moduleContext;
private static Test test;
static {
 moduleContext = new ClassPathXmlApplicationContext(new String[]{"beans-circile.xml"});
 test = (Test) moduleContext.getBean("test");
}
public static void main(String[] args) {
 System.out.println(test.name);
}
}

public Object getObject() throws Exception {
// TODO Auto-generated method stub
if(null == test){
 afterPropertiesSet();
}
return test;
}

public void afterPropertiesSet() throws Exception {
if(null == test){
 System.out.println("name:" + this.name);
 test = new Test();
 test.name = depentBean.doSomething() + this.name;
}
}

<bean id="dependentBean" class="com.alibaba.test.circle.DependentBean"></bean>
<bean id="test" class="com.alibaba.test.circle.MyFactoryBean">
<property name="depentBean">
 <ref bean="dependentBean" /> 
</property>
<property name="name" value="zlx"></property>
</bean>

public class UseTest {
@Autowired
private Test test;
}

<bean id="useTest" class="com.alibaba.test.circle.UseTest"></bean>
<bean id="dependentBean" class="com.alibaba.test.circle.DependentBean"></bean>
<bean id="test" class="com.alibaba.test.circle.MyFactoryBean">
<property name="depentBean">
 <ref bean="dependentBean" /> 
</property>
<property name="name" value="zlx"></property>
</bean>