AOP原理——2. AbstractAutoProxyCreator 创建动态代理对象

SmartInstantiationAwareBeanPostProcessor接口继承自InstantiationAwareBeanPostProcessor接口，因此AbstractAutoProxyCreator是通过InstantiationAwareBeanPostProcessor接口的postProcessBeforeInstantiation方法来生成动态代理对象的。

public abstract class AbstractAutoProxyCreator extends ProxyProcessorSupport implements SmartInstantiationAwareBeanPostProcessor, BeanFactoryAware {
	@Override
	public Object postProcessBeforeInstantiation(Class<?> beanClass, String beanName) {
		Object cacheKey = getCacheKey(beanClass, beanName);

		if (!StringUtils.hasLength(beanName) || !this.targetSourcedBeans.contains(beanName)) {
			if (this.advisedBeans.containsKey(cacheKey)) {
				return null;
			}
			if (isInfrastructureClass(beanClass) || shouldSkip(beanClass, beanName)) {
				this.advisedBeans.put(cacheKey, Boolean.FALSE);
				return null;
			}
		}

		// Create proxy here if we have a custom TargetSource.
		// Suppresses unnecessary default instantiation of the target bean:
		// The TargetSource will handle target instances in a custom fashion.
		TargetSource targetSource = getCustomTargetSource(beanClass, beanName);
		if (targetSource != null) {
			if (StringUtils.hasLength(beanName)) {
				this.targetSourcedBeans.add(beanName);
			}
			Object[] specificInterceptors = getAdvicesAndAdvisorsForBean(beanClass, beanName, targetSource);
			// 创建动态代理对象
			Object proxy = createProxy(beanClass, beanName, specificInterceptors, targetSource);
			this.proxyTypes.put(cacheKey, proxy.getClass());
			return proxy;
		}

		return null;
	}
}

createProxy

	protected Object createProxy(Class<?> beanClass, @Nullable String beanName, @Nullable Object[] specificInterceptors, TargetSource targetSource) {
		if (this.beanFactory instanceof ConfigurableListableBeanFactory) {
			AutoProxyUtils.exposeTargetClass((ConfigurableListableBeanFactory) this.beanFactory, beanName, beanClass);
		}

		ProxyFactory proxyFactory = new ProxyFactory();
		proxyFactory.copyFrom(this);

		if (!proxyFactory.isProxyTargetClass()) {
			if (shouldProxyTargetClass(beanClass, beanName)) {
				proxyFactory.setProxyTargetClass(true);
			}
			else {
				evaluateProxyInterfaces(beanClass, proxyFactory);
			}
		}

		Advisor[] advisors = buildAdvisors(beanName, specificInterceptors);
		proxyFactory.addAdvisors(advisors);
		proxyFactory.setTargetSource(targetSource);
		customizeProxyFactory(proxyFactory);

		proxyFactory.setFrozen(this.freezeProxy);
		if (advisorsPreFiltered()) {
			proxyFactory.setPreFiltered(true);
		}

		// 生成动态代理对象
		return proxyFactory.getProxy(getProxyClassLoader());
	}

proxyFactory.getProxy

	public Object getProxy(@Nullable ClassLoader classLoader) {
		// 调用 AopProxy 接口的 getProxy 方法，事实上就是选择 CGLIB 还是 JDK 的动态代理方式。
		return createAopProxy().getProxy(classLoader);
	}

public interface AopProxy {

	/**
	 * Create a new proxy object.
	 * <p>Uses the AopProxy's default class loader (if necessary for proxy creation):
	 * usually, the thread context class loader.
	 * @return the new proxy object (never {@code null})
	 * @see Thread#getContextClassLoader()
	 */
	Object getProxy();

	/**
	 * Create a new proxy object.
	 * <p>Uses the given class loader (if necessary for proxy creation).
	 * {@code null} will simply be passed down and thus lead to the low-level
	 * proxy facility's default, which is usually different from the default chosen
	 * by the AopProxy implementation's {@link #getProxy()} method.
	 * @param classLoader the class loader to create the proxy with
	 * (or {@code null} for the low-level proxy facility's default)
	 * @return the new proxy object (never {@code null})
	 */
	Object getProxy(@Nullable ClassLoader classLoader);

}

标签：Object,return,beanName,代理,proxy,proxyFactory,AOP,beanClass,AbstractAutoProxyCrea
来源： https://blog.csdn.net/jxch____/article/details/110531511