spring-扩展点-BeanPostProcessor

BeanFactoryPostProcessor和BeanPostProcessor，这两个接口， 都是Spring初始化bean时对外暴露的扩展点。两个接口名称看起来很相似，但作用及使用场景却不同，分析如下：

1、BeanFactoryPostProcessor接口

该接口的定义如下：

 public interface BeanFactoryPostProcessor {

     /**
      * Modify the application context's internal bean factory after its standard
      * initialization. All bean definitions will have been loaded, but no beans
      * will have been instantiated yet. This allows for overriding or adding
      * properties even to eager-initializing beans.
      * @param beanFactory the bean factory used by the application context
      * @throws org.springframework.beans.BeansException in case of errors
      */
     void postProcessBeanFactory(ConfigurableListableBeanFactory beanFactory) throws BeansException;

 }

实现该接口，可以在spring的bean创建之前，修改bean的定义属性（包含元数据）。也就是说，Spring允许BeanFactoryPostProcessor在容器实例化任何其它bean之前读取配置元数据，并可以根据需要进行修改，例如可以把bean的scope从singleton改为prototype，也可以把property的值给修改掉。可以同时配置多个BeanFactoryPostProcessor，并通过设置'order'属性来控制各个BeanFactoryPostProcessor的执行次序。
注意：BeanFactoryPostProcessor是在spring容器加载了bean的定义文件之后，在bean实例化之前执行的。接口方法的入参是ConfigurrableListableBeanFactory，使用该参数，可以获取到相关bean的定义信息，例子：

1）spring bean的定义：

 xml version="1.0" encoding="UTF-8" ?>
 <beans xmlns="http://www.springframework.org/schema/beans"
     xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xmlns:context="http://www.springframework.org/schema/context"
     xmlns:p="http://www.springframework.org/schema/p" xmlns:tx="http://www.springframework.org/schema/tx"
     xmlns:aop="http://www.springframework.org/schema/aop"
     xsi:schemaLocation="http://www.springframework.org/schema/beans http://www.springframework.org/schema/beans/spring-beans-2.5.xsd
                 http://www.springframework.org/schema/context http://www.springframework.org/schema/context/spring-context-2.5.xsd
                 http://www.springframework.org/schema/tx http://www.springframework.org/schema/tx/spring-tx-2.5.xsd"
     default-autowire="byName">

     <bean id="myJavaBean" class="com.ali.caihj.postprocessor.MyJavaBean">
         <property name="desc" value="测试一下啦" />
         <property name="remark" value="这是备注信息啦啦啦" />
     bean>
     <bean id="myBeanFactoryPostProcessor" class="com.ali.caihj.postprocessor.MyBeanFactoryPostProcessor" />
 beans>

2）自定义的BeanFactoryPostProcessor：

 public class MyBeanFactoryPostProcessor implements BeanFactoryPostProcessor {

     public void postProcessBeanFactory(ConfigurableListableBeanFactory beanFactory) throws BeansException {
         System.out.println("调用MyBeanFactoryPostProcessor的postProcessBeanFactory");
         BeanDefinition bd = beanFactory.getBeanDefinition("myJavaBean");
         System.out.println("属性值============" + bd.getPropertyValues().toString());
         MutablePropertyValues pv =  bd.getPropertyValues();
         if (pv.contains("remark")) {
      //修改定义属性值
             pv.addPropertyValue("remark", "把备注信息修改一下");
         }
 //修改定义的元数据
         bd.setScope(BeanDefinition.SCOPE_PROTOTYPE);
     }

 }

spring中，有内置的一些BeanFactoryPostProcessor实现类，常用的有：

• org.springframework.beans.factory.config.PropertyPlaceholderConfigurer
• org.springframework.beans.factory.config.PropertyOverrideConfigurer
• org.springframework.beans.factory.config.CustomEditorConfigurer：用来注册自定义的属性编辑器
  

2、BeanPostProcessor接口

该接口的定义如下：

 public interface BeanPostProcessor {

     /**
      * Apply this BeanPostProcessor to the given new bean instance before any bean
      * initialization callbacks (like InitializingBean's afterPropertiesSet
      * or a custom init-method). The bean will already be populated with property values.
      * The returned bean instance may be a wrapper around the original.
      * @param bean the new bean instance
      * @param beanName the name of the bean
      * @return the bean instance to use, either the original or a wrapped one
      * @throws org.springframework.beans.BeansException in case of errors
      * @see org.springframework.beans.factory.InitializingBean#afterPropertiesSet
      */
     Object postProcessBeforeInitialization(Object bean, String beanName) throws BeansException;

     /**
      * Apply this BeanPostProcessor to the given new bean instance after any bean
      * initialization callbacks (like InitializingBean's afterPropertiesSet
      * or a custom init-method). The bean will already be populated with property values.
      * The returned bean instance may be a wrapper around the original.
      * In case of a FactoryBean, this callback will be invoked for both the FactoryBean
      * instance and the objects created by the FactoryBean (as of Spring 2.0). The
      * post-processor can decide whether to apply to either the FactoryBean or created
      * objects or both through corresponding bean instanceof FactoryBean checks.
      * This callback will also be invoked after a short-circuiting triggered by a
      * {@link InstantiationAwareBeanPostProcessor#postProcessBeforeInstantiation} method,
      * in contrast to all other BeanPostProcessor callbacks.
      * @param bean the new bean instance
      * @param beanName the name of the bean
      * @return the bean instance to use, either the original or a wrapped one
      * @throws org.springframework.beans.BeansException in case of errors
      * @see org.springframework.beans.factory.InitializingBean#afterPropertiesSet
      * @see org.springframework.beans.factory.FactoryBean
      */
     Object postProcessAfterInitialization(Object bean, String beanName) throws BeansException;

 }

BeanPostProcessor，可以在spring容器实例化bean之后，在执行bean的初始化方法前后，添加一些自己的处理逻辑。这里说的初始化方法，指的是下面两种：

1）bean实现了InitializingBean接口，对应的方法为afterPropertiesSet

2）在bean定义的时候，通过init-method设置的方法

注意：BeanPostProcessor是在spring容器加载了bean的定义文件并且实例化bean之后执行的。BeanPostProcessor的执行顺序是在BeanFactoryPostProcessor之后。

spring中，有内置的一些BeanPostProcessor实现类，例如：

• org.springframework.context.annotation.CommonAnnotationBeanPostProcessor：支持@Resource注解的注入
• org.springframework.beans.factory.annotation.RequiredAnnotationBeanPostProcessor：支持@Required注解的注入
• org.springframework.beans.factory.annotation.AutowiredAnnotationBeanPostProcessor：支持@Autowired注解的注入
• org.springframework.orm.jpa.support.PersistenceAnnotationBeanPostProcessor：支持@PersistenceUnit和@PersistenceContext注解的注入
• org.springframework.context.support.ApplicationContextAwareProcessor：用来为bean注入ApplicationContext等容器对象
  

这些注解类的BeanPostProcessor，在spring配置文件中，可以通过这样的配置 ，自动进行注册。（spring通过ComponentScanBeanDefinitionParser类来解析该标签）

3、下面通过完整的一个例子，来加深理解

1）定义一个JavaBean

 public class MyJavaBean implements InitializingBean {
     private String desc;
     private String remark;

     public MyJavaBean() {
         System.out.println("MyJavaBean的构造函数被执行啦");
     }
     public String getDesc() {
         return desc;
     }
     public void setDesc(String desc) {
         System.out.println("调用setDesc方法");
         this.desc = desc;
     }
     public String getRemark() {
         return remark;
     }
     public void setRemark(String remark) {
         System.out.println("调用setRemark方法");
         this.remark = remark;
     }
     public void afterPropertiesSet() throws Exception {
         System.out.println("调用afterPropertiesSet方法");
         this.desc = "在初始化方法中修改之后的描述信息";
     }
     public void initMethod() {
         System.out.println("调用initMethod方法");
     }
     public String toString() {
         StringBuilder builder = new StringBuilder();
         builder.append("[描述：").append(desc);
         builder.append("， 备注：").append(remark).append("]");
         return builder.toString();
     }
 }

2）定义一个BeanFactoryPostProcessor

 public class MyBeanFactoryPostProcessor implements BeanFactoryPostProcessor {

     public void postProcessBeanFactory(ConfigurableListableBeanFactory beanFactory) throws BeansException {
         System.out.println("调用MyBeanFactoryPostProcessor的postProcessBeanFactory");
         BeanDefinition bd = beanFactory.getBeanDefinition("myJavaBean");
         MutablePropertyValues pv =  bd.getPropertyValues();
         if (pv.contains("remark")) {
             pv.addPropertyValue("remark", "在BeanFactoryPostProcessor中修改之后的备忘信息");
         }
     }

 }

3）定义一个BeanPostProcessor

 public class MyBeanPostProcessor implements BeanPostProcessor {

     public Object postProcessBeforeInitialization(Object bean, String beanName) throws BeansException {
         System.out.println("BeanPostProcessor，对象" + beanName + "调用初始化方法之前的数据： " + bean.toString());
         return bean;
     }
     public Object postProcessAfterInitialization(Object bean, String beanName) throws BeansException {
         System.out.println("BeanPostProcessor，对象" + beanName + "调用初始化方法之后的数据：" + bean.toString());
         return bean;
     }
 }

4）spring的配置

 "1.0" encoding="UTF-8" ?>
 "http://www.springframework.org/schema/beans"
     xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xmlns:context="http://www.springframework.org/schema/context"
     xmlns:p="http://www.springframework.org/schema/p" xmlns:tx="http://www.springframework.org/schema/tx"
     xmlns:aop="http://www.springframework.org/schema/aop"
     xsi:schemaLocation="http://www.springframework.org/schema/beans http://www.springframework.org/schema/beans/spring-beans-2.5.xsd
                 http://www.springframework.org/schema/context http://www.springframework.org/schema/context/spring-context-2.5.xsd
                 http://www.springframework.org/schema/tx http://www.springframework.org/schema/tx/spring-tx-2.5.xsd"
     default-autowire="byName">

     "myJavaBean" class="com.ali.caihj.postprocessor.MyJavaBean" init-method="initMethod">
         "desc" value="原始的描述信息" />
         "remark" value="原始的备注信息" />


     "myBeanPostProcessor" class="com.ali.caihj.postprocessor.MyBeanPostProcessor" />
     "myBeanFactoryPostProcessor" class="com.ali.caihj.postprocessor.MyBeanFactoryPostProcessor" />

5）测试类

 public class PostProcessorMain {
     public static void main(String[] args) {
         ApplicationContext context = new ClassPathXmlApplicationContext("config/postprocessor.xml");
         MyJavaBean bean = (MyJavaBean) context.getBean("myJavaBean");
         System.out.println("===============下面输出结果============");
         System.out.println("描述：" + bean.getDesc());
         System.out.println("备注：" + bean.getRemark());

     }
 }

6）运行结果如下：

7）分析

从上面的结果可以看出，BeanFactoryPostProcessor在bean实例化之前执行，之后实例化bean（调用构造函数，并调用set方法注入属性值），然后在调用两个初始化方法前后，执行了BeanPostProcessor。初始化方法的执行顺序是，先执行afterPropertiesSet，再执行init-method。

4、进一步深入分析

在使用ApplicationContext启动spring容器的时候，在AbstractApplicationContext.refresh()方法中，完成相关初始化工作：

1）BeanFactoryPostProcessor.postProcessBeanFactory，是在第5步执行的，invokeBeanFactoryPostProcessors方法实现如下：

 /**
      * Instantiate and invoke all registered BeanFactoryPostProcessor beans,
      * respecting explicit order if given.
      * Must be called before singleton instantiation.
      */
     protected void invokeBeanFactoryPostProcessors(ConfigurableListableBeanFactory beanFactory) {
         // Invoke factory processors registered with the context instance.
         for (Iterator it = getBeanFactoryPostProcessors().iterator(); it.hasNext();) {
             BeanFactoryPostProcessor factoryProcessor = (BeanFactoryPostProcessor) it.next();
             factoryProcessor.postProcessBeanFactory(beanFactory);
         }

         // Do not initialize FactoryBeans here: We need to leave all regular beans
         // uninitialized to let the bean factory post-processors apply to them!
         String[] postProcessorNames =
                 beanFactory.getBeanNamesForType(BeanFactoryPostProcessor.class, true, false);

         // Separate between BeanFactoryPostProcessors that implement PriorityOrdered,
         // Ordered, and the rest.
         List priorityOrderedPostProcessors = new ArrayList();
         List orderedPostProcessorNames = new ArrayList();
         List nonOrderedPostProcessorNames = new ArrayList();
         for (int i = 0; i < postProcessorNames.length; i++) {
             if (isTypeMatch(postProcessorNames[i], PriorityOrdered.class)) {
                 priorityOrderedPostProcessors.add(beanFactory.getBean(postProcessorNames[i]));
             }
             else if (isTypeMatch(postProcessorNames[i], Ordered.class)) {
                 orderedPostProcessorNames.add(postProcessorNames[i]);
             }
             else {
                 nonOrderedPostProcessorNames.add(postProcessorNames[i]);
             }
         }

         // First, invoke the BeanFactoryPostProcessors that implement PriorityOrdered.
         Collections.sort(priorityOrderedPostProcessors, new OrderComparator());
         invokeBeanFactoryPostProcessors(beanFactory, priorityOrderedPostProcessors);

         // Next, invoke the BeanFactoryPostProcessors that implement Ordered.
         List orderedPostProcessors = new ArrayList();
         for (Iterator it = orderedPostProcessorNames.iterator(); it.hasNext();) {
             String postProcessorName = (String) it.next();
             orderedPostProcessors.add(getBean(postProcessorName));
         }
         Collections.sort(orderedPostProcessors, new OrderComparator());
         invokeBeanFactoryPostProcessors(beanFactory, orderedPostProcessors);

         // Finally, invoke all other BeanFactoryPostProcessors.
         List nonOrderedPostProcessors = new ArrayList();
         for (Iterator it = nonOrderedPostProcessorNames.iterator(); it.hasNext();) {
             String postProcessorName = (String) it.next();
             nonOrderedPostProcessors.add(getBean(postProcessorName));
         }
         invokeBeanFactoryPostProcessors(beanFactory, nonOrderedPostProcessors);
     }

     /**
      * Invoke the given BeanFactoryPostProcessor beans.
      */
     private void invokeBeanFactoryPostProcessors(ConfigurableListableBeanFactory beanFactory, List postProcessors) {
         for (Iterator it = postProcessors.iterator(); it.hasNext();) {
             BeanFactoryPostProcessor postProcessor = (BeanFactoryPostProcessor) it.next();
             postProcessor.postProcessBeanFactory(beanFactory);
         }
     }

通过beanFactory.getBeanNamesForType(BeanFactoryPostProcessor.class, true, false)，获取spring配置文件中定义的所有实现BeanFactoryPostProcessor接口的bean，然后根据优先级进行排序，之后对于每个BeanFactoryPostProcessor，调用postProcessBeanFactory方法。

2）而BeanPostProcessor的执行，取决于配置文件中bean的定义，如果定义的bean是singleton并且不是抽象类，也不延迟初始化，则BeanPostProcessor是在第11步中执行；而对于prototype的bean，BeanPostProcessor是在程序getBean的时候执行的。在第6步中，调用registerBeanPostProcessors方法，注册所有实现BeanPostProcessor接口的bean，该方法的实现如下：

 protected void registerBeanPostProcessors(ConfigurableListableBeanFactory beanFactory) {
         String[] postProcessorNames = beanFactory.getBeanNamesForType(BeanPostProcessor.class, true, false);

         // Register BeanPostProcessorChecker that logs an info message when
         // a bean is created during BeanPostProcessor instantiation, i.e. when
         // a bean is not eligible for getting processed by all BeanPostProcessors.
         int beanProcessorTargetCount = beanFactory.getBeanPostProcessorCount() + 1 + postProcessorNames.length;
         beanFactory.addBeanPostProcessor(new BeanPostProcessorChecker(beanFactory, beanProcessorTargetCount));

         // Separate between BeanPostProcessors that implement PriorityOrdered,
         // Ordered, and the rest.
         List priorityOrderedPostProcessors = new ArrayList();
         List orderedPostProcessorNames = new ArrayList();
         List nonOrderedPostProcessorNames = new ArrayList();
         for (int i = 0; i < postProcessorNames.length; i++) {
             if (isTypeMatch(postProcessorNames[i], PriorityOrdered.class)) {
                 priorityOrderedPostProcessors.add(beanFactory.getBean(postProcessorNames[i]));
             }
             else if (isTypeMatch(postProcessorNames[i], Ordered.class)) {
                 orderedPostProcessorNames.add(postProcessorNames[i]);
             }
             else {
                 nonOrderedPostProcessorNames.add(postProcessorNames[i]);
             }
         }

         // First, register the BeanPostProcessors that implement PriorityOrdered.
         Collections.sort(priorityOrderedPostProcessors, new OrderComparator());
         registerBeanPostProcessors(beanFactory, priorityOrderedPostProcessors);

         // Next, register the BeanPostProcessors that implement Ordered.
         List orderedPostProcessors = new ArrayList();
         for (Iterator it = orderedPostProcessorNames.iterator(); it.hasNext();) {
             String postProcessorName = (String) it.next();
             orderedPostProcessors.add(getBean(postProcessorName));
         }
         Collections.sort(orderedPostProcessors, new OrderComparator());
         registerBeanPostProcessors(beanFactory, orderedPostProcessors);

         // Finally, register all other BeanPostProcessors.
         List nonOrderedPostProcessors = new ArrayList();
         for (Iterator it = nonOrderedPostProcessorNames.iterator(); it.hasNext();) {
             String postProcessorName = (String) it.next();
             nonOrderedPostProcessors.add(getBean(postProcessorName));
         }
         registerBeanPostProcessors(beanFactory, nonOrderedPostProcessors);
     }

在第11步中，调用finishBeanFactoryInitialization方法，该方法通过调用DefaultListableBeanFactory.preInstantiateSingletons()，进行相关初始化工作：

从上面的代码可以看出，对于非抽象类、非延迟初始化的单例bean，在spring容器启动的时候调用getBean方法来实例化bean，并进行相关初始化工作，getBean方法最终调用AbstractAutowireCapableBeanFactory.doCreateBean方法，该方法的实现如下：

 protected Object doCreateBean(final String beanName, final RootBeanDefinition mbd, final Object[] args) {
         // Instantiate the bean.
         BeanWrapper instanceWrapper = null;
         if (mbd.isSingleton()) {
             instanceWrapper = (BeanWrapper) this.factoryBeanInstanceCache.remove(beanName);
         }
         if (instanceWrapper == null) {
             instanceWrapper = createBeanInstance(beanName, mbd, args);
         }
         final Object bean = (instanceWrapper != null ? instanceWrapper.getWrappedInstance() : null);
         Class beanType = (instanceWrapper != null ? instanceWrapper.getWrappedClass() : null);

         // Allow post-processors to modify the merged bean definition.
         synchronized (mbd.postProcessingLock) {
             if (!mbd.postProcessed) {
                 applyMergedBeanDefinitionPostProcessors(mbd, beanType, beanName);
                 mbd.postProcessed = true;
             }
         }

         // Eagerly cache singletons to be able to resolve circular references
         // even when triggered by lifecycle interfaces like BeanFactoryAware.
         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);
                 }
             });
         }

         // Initialize the bean instance.
         Object exposedObject = bean;
         try {
             populateBean(beanName, mbd, instanceWrapper);
             exposedObject = initializeBean(beanName, exposedObject, mbd);
         }
         catch (Throwable ex) {
             if (ex instanceof BeanCreationException && beanName.equals(((BeanCreationException) ex).getBeanName())) {
                 throw (BeanCreationException) ex;
             }
             else {
                 throw new BeanCreationException(mbd.getResourceDescription(), beanName, "Initialization of bean failed", ex);
             }
         }

         if (earlySingletonExposure) {
             Object earlySingletonReference = getSingleton(beanName, false);
             if (earlySingletonReference != null) {
                 if (exposedObject == bean) {
                     exposedObject = earlySingletonReference;
                 }
                 else if (!this.allowRawInjectionDespiteWrapping && hasDependentBean(beanName)) {
                     String[] dependentBeans = getDependentBeans(beanName);
                     Set actualDependentBeans = new LinkedHashSet(dependentBeans.length);
                     for (int i = 0; i < dependentBeans.length; i++) {
                         String dependentBean = dependentBeans[i];
                         if (!removeSingletonIfCreatedForTypeCheckOnly(dependentBean)) {
                             actualDependentBeans.add(dependentBean);
                         }
                     }
                     if (!actualDependentBeans.isEmpty()) {
                         throw new BeanCurrentlyInCreationException(beanName,
                                 "Bean with name '" + beanName + "' has been injected into other beans [" +
                                 StringUtils.collectionToCommaDelimitedString(actualDependentBeans) +
                                 "] 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.");
                     }
                 }
             }
         }

         // Register bean as disposable.
         registerDisposableBeanIfNecessary(beanName, bean, mbd);

         return exposedObject;
     }

在该方法中，首先调用createBeanInstance方法，创建bean实例对象（这个时候执行bean的构造方法），然后调用populateBean方法，对bean进行填充，注入相关依赖，之后再调用方法initializeBean，进行相关初始化工作，initializeBean方法的实现如下：

 protected Object initializeBean(String beanName, Object bean, RootBeanDefinition mbd) {
         if (bean instanceof BeanNameAware) {
             ((BeanNameAware) bean).setBeanName(beanName);
         }

         if (bean instanceof BeanClassLoaderAware) {
             ((BeanClassLoaderAware) bean).setBeanClassLoader(getBeanClassLoader());
         }

         if (bean instanceof BeanFactoryAware) {
             ((BeanFactoryAware) bean).setBeanFactory(this);
         }

         Object wrappedBean = bean;
         if (mbd == null || !mbd.isSynthetic()) {
             wrappedBean = applyBeanPostProcessorsBeforeInitialization(wrappedBean, beanName);
         }

         try {
             invokeInitMethods(beanName, wrappedBean, mbd);
         }
         catch (Throwable ex) {
             throw new BeanCreationException(
                     (mbd != null ? mbd.getResourceDescription() : null),
                     beanName, "Invocation of init method failed", ex);
         }

         if (mbd == null || !mbd.isSynthetic()) {
             wrappedBean = applyBeanPostProcessorsAfterInitialization(wrappedBean, beanName);
         }
         return wrappedBean;
     }

从上面的实现可以看出，先调用applyBeanPostProcessorsBeforeInitialization方法，执行每个BeanPostProcessor的postProcessBeforeInitialization，然后调用invokeInitMethods方法，执行bean的初始化方法，最后调用applyBeanPostProcessorsAfterInitialization方法，执行每个BeanPostProcessor的postProcessAfterInitialization方法。这三个方法的实现如下：

     public Object applyBeanPostProcessorsBeforeInitialization(Object existingBean, String beanName)
             throws BeansException {

         Object result = existingBean;
         for (Iterator it = getBeanPostProcessors().iterator(); it.hasNext();) {
             BeanPostProcessor beanProcessor = (BeanPostProcessor) it.next();
             result = beanProcessor.postProcessBeforeInitialization(result, beanName);
         }
         return result;
     }

     public Object applyBeanPostProcessorsAfterInitialization(Object existingBean, String beanName)
             throws BeansException {

         Object result = existingBean;
         for (Iterator it = getBeanPostProcessors().iterator(); it.hasNext();) {
             BeanPostProcessor beanProcessor = (BeanPostProcessor) it.next();
             result = beanProcessor.postProcessAfterInitialization(result, beanName);
         }
         return result;
     }
 protected void invokeInitMethods(String beanName, Object bean, RootBeanDefinition mbd)
             throws Throwable {

         boolean isInitializingBean = (bean instanceof InitializingBean);
         if (isInitializingBean && (mbd == null || !mbd.isExternallyManagedInitMethod("afterPropertiesSet"))) {
             if (logger.isDebugEnabled()) {
                 logger.debug("Invoking afterPropertiesSet() on bean with name '" + beanName + "'");
             }
             ((InitializingBean) bean).afterPropertiesSet();
         }

         String initMethodName = (mbd != null ? mbd.getInitMethodName() : null);
         if (initMethodName != null && !(isInitializingBean && "afterPropertiesSet".equals(initMethodName)) &&
                 !mbd.isExternallyManagedInitMethod(initMethodName)) {
             invokeCustomInitMethod(beanName, bean, initMethodName, mbd.isEnforceInitMethod());
         }
     }

从invokeInitMethods方法的实现可以看出，先执行afterPropertiesSet方法，然后再通过反射，执行init-method指定的方法。