Spring AOP系列之五：后置通知

编程技术  /  houtizong 发布于 3年前   237

和前置通知类似，
通过实现org.springframework.aop.AfterReturningAdvice来完成后置通知：

public class CarAfterAdvice implements AfterReturningAdvice {@Override// returnValue 方法返回值，其它和前置通知相同public void afterReturning(Object returnValue, Method method, Object[] args, Object target) throws Throwable {System.out.println("Welcome to come again");}}

Spring配置文件beans-after-advice.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="carAfterAdvice" class="com.john.spring.aop.CarAfterAdvice" />    <bean id="proxyBean" class="org.springframework.aop.framework.ProxyFactoryBean">  <property name="proxyInterfaces">  <value>com.john.spring.aop.Vehicle</value></property><property name="interceptorNames"><list><value>carAfterAdvice</value></list></property><property name="target"><ref bean="car" /></property>  </bean></beans>

测试：

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

输出：
Car name: Superb, price: 220000
Welcome to come again


附：
执行info()时，调用org.springframework.aop.framework.adapter.AfterReturningAdviceAdapter的getInterceptor方法：

public MethodInterceptor getInterceptor(Advisor advisor) {AfterReturningAdvice advice = (AfterReturningAdvice) advisor.getAdvice(); // 获取后置通知实例return new AfterReturningAdviceInterceptor(advice);}

然后调用org.springframework.aop.framework.adapter.AfterReturningAdviceInterceptor的invoke方法：

public Object invoke(MethodInvocation mi) throws Throwable {Object retVal = mi.proceed(); // 执行目标方法this.advice.afterReturning(retVal, mi.getMethod(), mi.getArguments(), mi.getThis()); // 执行后置通知方法return retVal;}