一个简单的spring AOP例子

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 )