介绍

Spring动态创建bean过程, 是如何进行选择使用 jdk还是cglib进行代理的, 可以通过源码进行解析

执行过程

通过断点进行跟踪主要执行过程在 DefaultAopProxyFactory, 通过判断条件是使用Cglib还是Jdk

相关源码解析

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public class DefaultAopProxyFactory implements AopProxyFactory, Serializable {

	@Override
	public AopProxy createAopProxy(AdvisedSupport config) throws AopConfigException {
	    //判断条件 是否优化, 返回是否直接代理目标类以及任何接口或者没有用户提供的代理接口
		if (config.isOptimize() || config.isProxyTargetClass() || hasNoUserSuppliedProxyInterfaces(config)) {
			Class<?> targetClass = config.getTargetClass();
			if (targetClass == null) {
				throw new AopConfigException("TargetSource cannot determine target class: " +
						"Either an interface or a target is required for proxy creation.");
			}
			//判断是否是接口, 和已经使用jdk代理
			if (targetClass.isInterface() || Proxy.isProxyClass(targetClass)) {
				return new JdkDynamicAopProxy(config);
			}
			return new ObjenesisCglibAopProxy(config);
		}
		else {
			return new JdkDynamicAopProxy(config);
		}
	}

	/**
	 * Determine whether the supplied {@link AdvisedSupport} has only the
	 * {@link org.springframework.aop.SpringProxy} interface specified
	 * (or no proxy interfaces specified at all).
	 */
	private boolean hasNoUserSuppliedProxyInterfaces(AdvisedSupport config) {
		Class<?>[] ifcs = config.getProxiedInterfaces();
		return (ifcs.length == 0 || (ifcs.length == 1 && SpringProxy.class.isAssignableFrom(ifcs[0])));
	}

}