Spring AOP之Advice

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Spring

Spring Advice

Spring AOP之Advice

   前置通知：即代码被执行之前被调用
   后置通知：即代码执行之后进行调用
   环绕通知：即代码执行前后进行调用

这两种方式的实现方式用到了动态代理的思想来完成的，

总结不想说废话：

首先是Spring1.x对Advice的支持：

public interface IHello {
	public void sayHello1() ;
	public void sayHello2() ;
	public void sayHello3() ;
	public void sayHello4() ;
}

然后就是类的实现：

package com.spring.test;

public class Hello implements IHello{

	public void sayHello1() {
		System.out.println("111111111111");
	}

	public void sayHello2() {
		System.out.println("222222222222");
	}

	public void sayHello3() {
		System.out.println("333333333333");
	}

	public void sayHello4() {
		System.out.println("444444444444");
	}
}

然后是负责前置通知的类，要实现MethodBeforeAdvice接口：

public class AdviceBeforeHello implements MethodBeforeAdvice {
	@Override
	public void before(Method arg0, Object[] arg1, Object arg2)
			throws Throwable {
		System.out.println("验证用户。。。。");

	}
}

然后是负责后置通知的类，要实现AfterReturningAdvice接口：

public class AdviceAfterHello implements AfterReturningAdvice{

	@Override
	public void afterReturning(Object arg0, Method arg1, Object[] arg2,
			Object arg3) throws Throwable {
		System.out.println("方法执行完毕");
		
	}

}

配置项：
<bean id="beforeHello" class="com.spring.advice.AdviceBeforeHello" />
	<bean id="afterHello" class="com.spring.advice.AdviceAfterHello"></bean>
	<bean id="hello" class="com.spring.test.Hello"></bean>
	<!-- 注册代理类 -->
	<bean id="proxy" class="org.springframework.aop.framework.ProxyFactoryBean">
		<property name="proxyInterfaces">
			<value>com.spring.test.IHello</value>
		</property>

		<!-- 目标对象，即Hello对象 -->
		<property name="target" ref="hello"></property>
		<!-- 应用的前置通知，拦截器名称 -->
		<property name="interceptorNames">
			<list>
				<value>beforeHello</value>
				<value>afterHello</value>

			</list>
		</property>
	</bean>

测试方法：

	ApplicationContext context = new ClassPathXmlApplicationContext("beans.xml");
		IHello hello = (IHello) context.getBean("proxy");
		hello.sayHello1();
		hello.sayHello2();
		hello.sayHello3();
		hello.sayHello4();

结果：

下面是环绕通知：

public class AdviceAroundHello implements MethodInterceptor{

	@Override
	public Object invoke(MethodInvocation arg0) throws Throwable {
		Object object=null;
		System.out.println("验证用户");
		try {
			object=arg0.proceed();
		} finally{
			System.out.println("方法执行完毕");
		}
		
		return object;
	}


}

然后配置beans.xml：

<bean id="aroundHello" class="com.spring.advice.AdviceAroundHello"></bean>
	 
	<bean id="hello" class="com.spring.test.Hello"></bean>
	<!-- 注册代理类 -->
	<bean id="proxy" class="org.springframework.aop.framework.ProxyFactoryBean">
		<property name="proxyInterfaces">
			<value>com.spring.test.IHello</value>
		</property>

		<!-- 目标对象，即Hello对象 -->
		<property name="target" ref="hello"></property>
		<!-- 应用的前置通知，拦截器名称 -->
		<property name="interceptorNames">
			<list>
				<value>aroundHello</value>
			</list>
		</property>
	</bean>

以上是Spring1.x对AOP的支持，，Spring2.x除了支持Spring1.x外，还提供了两种实现AOP的方式：

1.基于XML的配置，使用基于Schema的XML配置来完成AOP而且Advice也不用再实现任何其他特定接口。

2.使用JDK5的注释来完成AOP的实现，只需要一个简单的标签就可以完成AOP的整个过程。

基于XML Schema的前置通知配置如下：

编写通知的逻辑代码：

public class AdviceBeforeHello {
	public void beforeHello(){
		System.out.println("验证用户。。。。");

	}
}

在beans.xml中进行配置：

<?xml version="1.0" encoding="UTF-8"?>
<beans xmlns="http://www.springframework.org/schema/beans"
	xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
        xmlns:aop="http://www.springframework.org/schema/aop"
	xsi:schemaLocation="http://www.springframework.org/schema/beans
           http://www.springframework.org/schema/beans/spring-beans-2.5.xsd
           http://www.springframework.org/schema/aop
           http://www.springframework.org/schema/aop/spring-aop-2.5.xsd">
	<!-- 注册接口实现类 -->
	<bean id="hello" class="com.spring.test.Hello"></bean>
	<aop:config>
	<!--  -->
		<aop:pointcut id="beforePointCut"
			expression="execution(* com.spring.test.IHello.*(..))" />
		<aop:aspect id="before" ref="beforeAdvice">
			<aop:before method="beforeHello" pointcut-ref="beforePointCut" />
		</aop:aspect>
	</aop:config>


	<bean id="beforeAdvice" class="com.spring.advice.AdviceBeforeHello"></bean>
</beans>

其他不变。。。。

2.基于Annotation的前置通知：

切面类：

import org.aspectj.lang.annotation.Aspect;
import org.aspectj.lang.annotation.Before;

@Aspect
public class AdviceBeforeHello {
	@Before("execution(*  com.spring.test.IHello.*(..))")
	public void beforeHello(){
		System.out.println("验证用户。。。。");

	}
}

beans.xml配置:

<?xml version="1.0" encoding="UTF-8"?>
<beans xmlns="http://www.springframework.org/schema/beans"
	xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xmlns:aop="http://www.springframework.org/schema/aop"
	xsi:schemaLocation="http://www.springframework.org/schema/beans
           http://www.springframework.org/schema/beans/spring-beans-2.5.xsd
           http://www.springframework.org/schema/aop
           http://www.springframework.org/schema/aop/spring-aop-2.5.xsd">
	<!-- 注册接口实现类 -->
	<aop:aspectj-autoproxy></aop:aspectj-autoproxy>
	<bean id="hello" class="com.spring.test.Hello"></bean>
	<bean id="beforeAdvice" class="com.spring.advice.AdviceBeforeHello"></bean>
</beans>

基于XML和Annotation的后置通知和前置通知类似。下面是基于XML的环绕通知：

import org.aspectj.lang.ProceedingJoinPoint;

public class AdviceAroundHello {

	public Object around(ProceedingJoinPoint joinPoint) throws Throwable {
		System.out.println("验证用户");
		//执行连接点的方法
		Object object = joinPoint.proceed();
		System.out.println("方法执行完毕");
		return object;
	}

}

beans.xml配置：

<?xml version="1.0" encoding="UTF-8"?>
<beans xmlns="http://www.springframework.org/schema/beans"
	xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xmlns:aop="http://www.springframework.org/schema/aop"
	xsi:schemaLocation="http://www.springframework.org/schema/beans
           http://www.springframework.org/schema/beans/spring-beans-2.5.xsd
           http://www.springframework.org/schema/aop
           http://www.springframework.org/schema/aop/spring-aop-2.5.xsd">
	<!-- 注册接口实现类 -->
	<bean id="hello" class="com.spring.test.Hello"></bean>
	<aop:config>
		<aop:pointcut id="aroundPointcut"
			expression="execution(*  com.spring.test.IHello.*(..))" />
		<aop:aspect id="around" ref="aroundAdvice">
			<aop:around method="around" pointcut-ref="aroundPointcut" />
		</aop:aspect>
	</aop:config>

	<bean id="aroundAdvice" class="com.spring.advice.AdviceAroundHello"></bean>
</beans>

其他不变。

-------------------------------------------------------------------------------------------------------------------------------

基于Annotation的环绕通知：

package com.spring.advice;

import org.aspectj.lang.ProceedingJoinPoint;
import org.aspectj.lang.annotation.Around;
import org.aspectj.lang.annotation.Aspect;

@Aspect
public class AdviceAroundHello {
	@Around("execution(*  com.spring.test.IHello.*(..))")
	public Object around(ProceedingJoinPoint joinPoint) throws Throwable {
		System.out.println("验证用户");
		// 执行连接点的方法
		Object object = joinPoint.proceed();
		System.out.println("方法执行完毕");
		return object;
	}

}

beans.xml配置：

<?xml version="1.0" encoding="UTF-8"?>
<beans xmlns="http://www.springframework.org/schema/beans"
	xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xmlns:aop="http://www.springframework.org/schema/aop"
	xsi:schemaLocation="http://www.springframework.org/schema/beans
           http://www.springframework.org/schema/beans/spring-beans-2.5.xsd
           http://www.springframework.org/schema/aop
           http://www.springframework.org/schema/aop/spring-aop-2.5.xsd">
	<!-- 注册接口实现类 -->
	<aop:aspectj-autoproxy></aop:aspectj-autoproxy>
	
	<bean id="hello" class="com.spring.test.Hello"></bean>
	<bean id="aroundAdvice" class="com.spring.advice.AdviceAroundHello"></bean>
</beans>

完成！！