Spring AOP系列之三：环绕代理

通过实现org.aopalliance.intercept.MethodInterceptor接口来实现环绕通知：

public class CarAroundProxy implements MethodInterceptor {

	@Override
	public Object invoke(MethodInvocation invocation) throws Throwable {
		System.out.println("Skoda 4S shop");
		Object result = invocation.proceed();
		System.out.println("Give 200 maintenance coupon via around proxy");
		return result;
	}
}

Spring配置文件beans-around-proxy.xml：

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

  <bean id="car" class="com.john.spring.aop.Car">
  	<property name="name" value="Superb" />
	<property name="price" value="220000" />
  </bean>
  
  <bean id="carAroundProxy" class="com.john.spring.aop.CarAroundProxy" />
  
  <!-- 通过ProxyFactoryBean来生成实现指定接口，拦截指定对象方法的代理类 -->
  <bean id="proxyBean" class="org.springframework.aop.framework.ProxyFactoryBean">
  	<property name="proxyInterfaces"><!-- 代理需实现的接口 -->
  		<value>com.john.spring.aop.Vehicle</value>
	</property>
	<property name="interceptorNames"><!-- 拦截器名称列表 -->
		<list>
			<value>carAroundProxy</value>
		</list>
	</property>
	<property name="target"><!-- 目标对象 -->
		<ref bean="car" />
	</property>
  </bean>
</beans>

测试：

public static void main(String[] args) {
	ApplicationContext ctx = new ClassPathXmlApplicationContext(new String[] { "beans-around-proxy.xml" });
	Vehicle vehicle = (Vehicle) ctx.getBean("proxyBean");
	vehicle.info();
}

输出：
Skoda 4S shop
Car name: Superb, price: 220000
Give 200 maintenance coupon via around proxy

调试程序，vehicle使用JDK的代理生成：