一个简单的spring AOP例子

转自:http://meiowei.iteye.com/blog/413919

这个只是个简单AOP例子,包括前置通知，后置通知,环绕通知,和目标对象。写这个例子的主要目标只是想让想学AOP的能更快地入门，了解一下如何去配置AOP里面的东东。 
目标对象的接口:IStudent.java

 

  1   /**
  2  *
  3   */
  4  package  com.dragon.study;
  5
  6   /**
  7  *  @author  dragon
  8  *
  9   */
 10   public   interface  IStudent   {
 11
 12      public   void  addStudent(String name);
 13 }

 

目标类:StudentImpl.java

 1    /**
  2  *
  3   */
  4  package  com.dragon.study.Impl;
  5
  6  import  com.dragon.study.IStudent;
  7
  8    /**
  9  *  @author  dragon
 10  *
 11   */
 12   public   class  StudentImpl  implements  IStudent  {
 13
 14        public   void  addStudent(String name)  {
 15          System.out.println( " 欢迎  " + name + "  你加入Spring家庭! " );
 16      }
 17 }
 18

 

前置通知:BeforeAdvice.java

 1    /**
  2  *
  3   */
  4  package  com.dragon.Advice;
  5
  6  import  java.lang.reflect.Method;
  7
  8  import  org.springframework.aop.MethodBeforeAdvice;
  9
 10    /**
 11  *  @author  dragon
 12  *
 13   */
 14   public   class  BeforeAdvice  implements  MethodBeforeAdvice  {
 15
 16        public   void  before(Method method,Object[] args, Object target)
 17                  throws  Throwable  {
 18
 19           System.out.println( " 这是BeforeAdvice类的before方法. " );
 20
 21       }
 22 }

 

后置通知:AfterAdvice.java

 1/**
  2 *
  3 */
  4package com.dragon.Advice;
  5
  6import java.lang.reflect.Method;
  7
  8import org.springframework.aop.AfterReturningAdvice;
  9
 10/**
 11 * @author dragon
 12 *
 13 */
 14public class AfterAdvice implements AfterReturningAdvice{
 15
 16    public void afterReturning(Object returnValue ,Method method,
 17                   Object[] args,Object target) throws Throwable{
 18        System.out.println("这是AfterAdvice类的afterReturning方法.");
 19    }
 20
 21
 22}

 

环绕通知:CompareInterceptor.java

 1/**
  2 *
  3 */
  4package com.dragon.Advice;
  5
  6import org.aopalliance.intercept.MethodInterceptor;
  7import org.aopalliance.intercept.MethodInvocation;
  8
  9
 10/**
 11 * @author dragon
 12 *
 13 */
 14public class CompareInterceptor implements MethodInterceptor{
 15
 16      public Object invoke(MethodInvocation invocation) throws Throwable{
 17          Object result = null;
 18         String stu_name = invocation.getArguments()[0].toString();
 19         if ( stu_name.equals("dragon")){
 20             //如果学生是dragon时,执行目标方法,
 21              result= invocation.proceed();
 22
 23         } else{
 24             System.out.println("此学生是"+stu_name+"而不是dragon,不批准其加入.");
 25         }
 26
 27          return result;
 28      }
 29}

 

配置文件applicationContext.xml

 1<?xml version="1.0" encoding="UTF-8"?>
  2<!DOCTYPE beans PUBLIC "-//SPRING//DTD BEAN//EN" "http://www.springframework.org/dtd/spring-beans.dtd">
  3
  4<beans>
  5
  6<bean id="beforeAdvice" class="com.dragon.Advice.BeforeAdvice"></bean>
  7<bean id="afterAdvice" class="com.dragon.Advice.AfterAdvice"></bean>
  8<bean id="compareInterceptor" class="com.dragon.Advice.CompareInterceptor"></bean>
  9<bean id="studenttarget" class="com.dragon.study.Impl.StudentImpl"></bean>
 10
 11<bean id="student" class="org.springframework.aop.framework.ProxyFactoryBean">
 12  <property name="proxyInterfaces">
 13    <value>com.dragon.study.IStudent</value>
 14  </property>
 15  <property name="interceptorNames">
 16    <list>
 17     <value>beforeAdvice</value>
 18     <value>afterAdvice</value>
 19    <value>compareInterceptor</value>
 20    </list>
 21  </property>
 22  <property name="target">
 23    <ref bean="studenttarget"/>
 24  </property>
 25
 26</bean>
 27
 28</beans>

 

现在开始写测试类,Test.java

 1/**
  2 *
  3 */
  4package com;
  5
  6import org.springframework.context.ApplicationContext;
  7import org.springframework.context.support.FileSystemXmlApplicationContext;
  8
  9import com.dragon.study.IStudent;
 10
 11/**
 12 * @author dragon
 13 *
 14 */
 15public class Test {
 16
 17    /**
 18     * @param args
 19     */
 20    public static void main(String[] args) {
 21        // TODO Auto-generated method stub
 22      ApplicationContext ctx =
 23          new FileSystemXmlApplicationContext("/com/dragon/applicationContext.xml");
 24
 25      IStudent person = (IStudent)ctx.getBean("student");
 26      person.addStudent("dragon");
 27
 28//      person.addStudent("javadragon");
 29    }
 30
 31}
 32

 

当然，运行该程序时，要加上commons-logging.jar 包

 

在Spring Appactiocontext.xml配置文件；你定义的前置，后置；环绕等通知在配置文件中实现了代理（org.springframework.aop.framework.ProxyFactoryBean） 
以此将通知放入到了原Bean中；这样才能使原Bean中方法调用时自动执行通知 
这是其一》 
<property name="proxyInterfaces"> 
<property name="interceptorNames"> 
<property name="target"> 
这三个属性是一定要配置的 
第一是被代理的接口（IStudent） 
第二是通知列表（前置，后置；环绕）上面定义的三个类 
第三是被代理的原Bean(StudentImpl )