该工厂bean的getObject代码如下:
public Object getObject() throws BeansException {
initializeAdvisorChain();
if (isSingleton()) {
return getSingletonInstance();
}
else {
if (this.targetName == null) {
logger.info("Using non-singleton proxies with singleton targets is often undesirable. " +
"Enable prototype proxies by setting the 'targetName' property.");
}
return newPrototypeInstance();
}
}
该方法主要包含两部分内容:初始化advisor链,返回singleton instance.
其中调用的initializeAdvisorChain方法代码如下:
private synchronized void initializeAdvisorChain() throws AopConfigException, BeansException {
if (this.advisorChainInitialized) {
return;
}
if (!ObjectUtils.isEmpty(this.interceptorNames)) {
if (this.beanFactory == null) {
throw new IllegalStateException("No BeanFactory available anymore (probably due to serialization) " +
"- cannot resolve interceptor names " + Arrays.asList(this.interceptorNames));
}
// Globals can't be last unless we specified a targetSource using the property...
if (this.interceptorNames[this.interceptorNames.length - 1].endsWith(GLOBAL_SUFFIX) &&
this.targetName == null && this.targetSource == EMPTY_TARGET_SOURCE) {
throw new AopConfigException("Target required after globals");
}
// Materialize interceptor chain from bean names.
for (String name : this.interceptorNames) {
if (name.endsWith(GLOBAL_SUFFIX)) {
if (!(this.beanFactory instanceof ListableBeanFactory)) {
throw new AopConfigException(
"Can only use global advisors or interceptors with a ListableBeanFactory");
}
addGlobalAdvisors((ListableBeanFactory) this.beanFactory,
name.substring(0, name.length() - GLOBAL_SUFFIX.length()));
}
else {
// If we get here, we need to add a named interceptor.
// We must check if it's a singleton or prototype.
Object advice;
if (this.singleton || this.beanFactory.isSingleton(name)) {
// Add the real Advisor/Advice to the chain.
advice = this.beanFactory.getBean(name);
}
else {
// It's a prototype Advice or Advisor: replace with a prototype.
// Avoid unnecessary creation of prototype bean just for advisor chain initialization.
advice = new PrototypePlaceholderAdvisor(name);
}
addAdvisorOnChainCreation(advice);
}
}
}
this.advisorChainInitialized = true;
}
主要是遍历给ProxyFactoryBean配置的interceptorNames,对每个name,从bean factory中获取bean,然后调用addAdvisorOnCreation将其添加到advisor chain中:
然后调用getSingletonInstance方法,该方法代码如下:
其中this.singletonInstance = getProxy(createAopProxy());就创建了代理对象。
其中createAopProxy的代码如下(位于DefaultAopProxyFactory类):
它会返回一个ObjenesisAopProxy或者JdkDynamicAopProxy对象,然后把它传递给getProxy方法,而getProxy方法代码如下:
该getProxy调用的getProxy方法在JdkDynamicAopProxy中的实现如下:
可见其使用了Jdk 动态代理生成了一个Proxy的子类的对象然后返回。