最近深入的學習了一下 Spring, 感受到了 AOP 的威力，以前看過 BEA 的 DEV2DEV 雜志，有一期專門的 AOP ，里面很詳細講的，看了有一年多了，今天真正來作個例子

?

這個例子也是從 dev2dev 上看的，

1 ：建一個接口 IBusinessLogic

?

package test;

?

public interface IBusinessLogic {

?????? public void foo(String i);

?

}

2 ：建一個接口實現的類

package test;

?

public class BusinessLogic implements IBusinessLogic {

?

?????? public void foo(String i) {

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

?

?????? }

?

}

?

3 建立一個應用程序 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 >

?

紅色的暫時不配置，你就可以看到打印出來的結果

Inside BusinessLogic.foo()

?

4 ：建立 2 個類 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() +

?????? ")");

?}

}

然后把紅色部分的配置上去，

運行 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 在方法開始和技術的時候起到了作用！！！