公司要求分享技术，一个小组九个人，每周一个人，想想讲讲AOP吧，用处也挺大的，果断写了一个小例子，改了改也就成了。这是个简单AOP例子，包括前置通知，后置通知，环绕通知，和目标对象。

目标对象的接口:IStudent.java

package  com.dragon.study;

/**

*  @author  ysm

*/

public   interface  IStudent  {

public   void  addStudent(String name);

}

目标类:StudentImpl.java

package  com.dragon.study.Impl;

import  com.dragon.study.IStudent;

/**

*  @author  ysm

*/

public   class  StudentImpl  implements  IStudent {

public   void  addStudent(String name) {

System.out.println( " 欢迎  " + name + "  加入Spring家庭! " );

}

}

前置通知:BeforeAdvice.java

package  com.dragon.Advice;

import  java.lang.reflect.Method;

import  org.springframework.aop.MethodBeforeAdvice;

/**

*  @author  ysm

*/

public   class  BeforeAdvice  implements  MethodBeforeAdvice {

public   void  before(Method method,Object[] args, Object target) throws  Throwable {

System.out.println( " 这是BeforeAdvice类的before方法. " );

}

}

后置通知:AfterAdvice.java

package com.dragon.Advice;

import java.lang.reflect.Method;

import org.springframework.aop.AfterReturningAdvice;

/**

* @author ysm

*/

public class AfterAdvice implements AfterReturningAdvice{

public void afterReturning(Object returnValue ,Method method,Object[] args,Object target) throws Throwable{

System.out.println("这是AfterAdvice类的afterReturning方法.");

}

}

环绕通知:CompareInterceptor.java

package com.dragon.Advice;

import org.aopalliance.intercept.MethodInterceptor;

import org.aopalliance.intercept.MethodInvocation;

/**

* @author ysm

*/

public class CompareInterceptor implements MethodInterceptor{

public Object invoke(MethodInvocation invocation) throws Throwable{

Object result = null;

String stu_name = invocation.getArguments()[0].toString();

if ( stu_name.equals("ysm")){

//如果学生是ysm时,执行目标方法,

result= invocation.proceed();

} else{

System.out.println("此学生是"+stu_name+"而不是ysm,不批准其加入.");

}

return result;

}

}

配置文件applicationContext.xml

<?xml version="1.0" encoding="UTF-8"?>

<!DOCTYPE beans PUBLIC "-//SPRING//DTD BEAN//EN" "http://www.springframework.org/dtd/spring-beans.dtd">

<beans>

<bean id="beforeAdvice" class="com.dragon.Advice.BeforeAdvice"></bean>

<bean id="afterAdvice" class="com.dragon.Advice.AfterAdvice"></bean>

<bean id="compareInterceptor" class="com.dragon.Advice.CompareInterceptor"></bean>

<bean id="studenttarget" class="com.dragon.study.Impl.StudentImpl"></bean>

<bean id="student" class="org.springframework.aop.framework.ProxyFactoryBean">

<property name="proxyInterfaces">

<value>com.dragon.study.IStudent</value>

</property>

<property name="interceptorNames">

<list>

<value>beforeAdvice</value>

<value>afterAdvice</value>

<value>compareInterceptor</value>

</list>

</property>

<property name="target">

<ref bean="studenttarget"/>

</property>

</bean>

</beans>

现在开始写测试类,Test.java

package com;

import org.springframework.context.ApplicationContext;

import org.springframework.context.support.FileSystemXmlApplicationContext;

import com.dragon.study.IStudent;

/**

* @author ysm

*/

public class Test {

/**

* @param args

*/

public static void main(String[] args) {

// TODO Auto-generated method stub

ApplicationContext ctx = new FileSystemXmlApplicationContext("/com/dragon/applicationContext.xml");

IStudent person = (IStudent)ctx.getBean("student");

person.addStudent("ysm");

//person.addStudent("javadragon");

}

}