最近深入的学习了一下 Spring, 感受到了 AOP 的威力，以前看过 BEA 的 DEV2DEV 杂志，有一期专门的 AOP ，里面很详细讲的，看了有一年多了，今天真正来作个例子

 

这个例子也是从 dev2dev 上看的，

1 ：建一个接口 IBusinessLogic

 

package test;

 

public interface IBusinessLogic {

       public void foo(String i);

 

}

2 ：建一个接口实现的类

package test;

 

public class BusinessLogic implements IBusinessLogic {

 

       public void foo(String i) {

              System.out.println("Inside BusinessLogic.foo()");

 

       }

 

}

 

3 建立一个应用程序 MainApplication

 

       public static void main(String[] args) {

               // Read the configuration file

        ApplicationContext ctx =

          new FileSystemXmlApplicationContext(

            "E:\\work\\Test\\src\\spring-config.xml");

        //Instantiate an object

        IBusinessLogic testObject =

          (IBusinessLogic) ctx.getBean("businesslogicbean");

        testObject.foo("11");

       }

 

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

<! DOCTYPE beans PUBLIC

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

 

< beans >

 

   <!-- Bean configuration -->

   < bean id = "businesslogicbean"

   class = "org.springframework.aop.framework.ProxyFactoryBean" >

      < property name = "proxyInterfaces" >

         < value > test.IBusinessLogic </ value >

      </ property >

      < property name = "target" >

         < ref local = "beanTarget" />

      </ property >

     <property name="interceptorNames">

         <list>

            <value>theTracingBeforeAdvisor</value>

            <value>theTracingAfterAdvisor</value>

         </list>

         </property>

    

   </ bean >

   <!-- Bean Classes -->

   < bean id = "beanTarget"

   class = "test.BusinessLogic" />

  

      <bean id="theTracingBeforeAdvisor"

      class="org.springframework.aop.support.RegexpMethodPointcutAdvisor">

      <property name="advice">

         <ref local="theTracingBeforeAdvice"/>

      </property>

      <property name="pattern">

         <value>.*</value>

      </property>

   </bean>

   

   <!-- Advisor pointcut definition for after advice -->

   <bean id="theTracingAfterAdvisor"

      class="org.springframework.aop.support.RegexpMethodPointcutAdvisor">

      <property name="advice">

         <ref local="theTracingAfterAdvice"/>

      </property>

      <property name="pattern">

         <value>.*</value>

      </property>

   </bean>

 

   <!-- Advice classes -->

   <bean id="theTracingBeforeAdvice"

      class="test.TracingBeforeAdvice"/>

   <bean id="theTracingAfterAdvice"

      class="test.TracingAfterAdvice"/>

     

     

 

</ beans >

 

红色的暂时不配置，你就可以看到打印出来的结果

Inside BusinessLogic.foo()

 

4 ：建立 2 个类 TracingBeforeAdvice

 

package test;

 

import java.lang.reflect.Method;

 

import org.springframework.aop.MethodBeforeAdvice;

 

public class TracingBeforeAdvice implements MethodBeforeAdvice {

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

              System.out.println(m.getClass());

              System.out.println(args);

              System.out.println(target);

              System.out.println("Hello world! (by " + this.getClass().getName()

                            + ")");

       }

}

 

 

TracingAfterAdvice

package test;

 

import java.lang.reflect.Method;

 

import org.springframework.aop.AfterReturningAdvice;

 

public class TracingAfterAdvice

implements AfterReturningAdvice

{

 public void afterReturning(Object object,

                          Method m,

                          Object[] args,

                          Object target)

                          throws Throwable

 {

     System.out.println(

       "Hello world! (by " +

       this.getClass().getName() +

       ")");

 }

}

然后把红色部分的配置上去，

运行 MainApplication

你就可以看到

//class java.lang.reflect.Method

//[Ljava.lang.Object;@3a9bba

//test.BusinessLogic@1c5ddc9

Hello world! (by test.TracingBeforeAdvice)

Inside BusinessLogic.foo()

Hello world! (by test.TracingAfterAdvice)

 

AOP 在方法开始和技术的时候起到了作用！！！