前面了解了典型的AOP基于配置的使用方法,下面介绍下如何依赖于注解来实现AOP。
基于注解降低了配置文件的复杂程度,但是引入了程序间的耦合,其中的优劣待用户自己判断了。
需要注意的是,确定AspectJ与JDK之间的版本,否则会报错,详情请见。
首先看一下基于注解的切面类,这时的切面不仅仅是一个POJO类了,与AOP进行了紧密的耦合。但是配置过程和方式都与原来的方式差不多。
package com.spring.test.chap44; import org.aspectj.lang.annotation.AfterReturning; import org.aspectj.lang.annotation.AfterThrowing; import org.aspectj.lang.annotation.Aspect; import org.aspectj.lang.annotation.Before; import org.aspectj.lang.annotation.Pointcut; import org.springframework.stereotype.Component; @Component @Aspect public class Audience { @Pointcut("execution(* com.spring.test.chap44.Instrumentalist.perform(..))") public void performance(){} @Before("performance()") public void takeSeats(){ System.out.println("takeSeats()"); } @Before("performance()") public void turnOffCellphones(){ System.out.println("turnOffCellphones()"); } @AfterReturning("performance()") public void applaud(){ System.out.println("applaud()"); } @AfterThrowing("performance()") public void demandRefund(){ System.out.println("demandRefund()"); } }
接下来是其他一些必不可少的类:
切点接口类:
package com.spring.test.chap44; public interface Performer { public void perform(); }
切点实现类:
package com.spring.test.chap44; import org.springframework.stereotype.Component; @Component public class Instrumentalist implements Performer{ public void perform() { System.out.println("__________ perform ___________"); } }
测试类:
package com.spring.test.chap44; import org.springframework.context.ApplicationContext; import org.springframework.context.support.ClassPathXmlApplicationContext; public class test { public static void main(String[] args) { ApplicationContext ctx = new ClassPathXmlApplicationContext("bean.xml"); Performer performer = (Performer)ctx.getBean("xingoo"); performer.perform(); } }
下面是重点的配置文件
此时的配置文件注意要使spring知道哪一个是普通的bean,哪一个是通知。因此需要加上一个属性,保证AOP自动的识别通知。
<aop:aspectj-autoproxy proxy-target-class="true"/>
配置文件如下:
<?xml version="1.0" encoding="UTF-8"?> <beans xmlns="http://www.springframework.org/schema/beans" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xmlns:context="http://www.springframework.org/schema/context" xmlns:aop="http://www.springframework.org/schema/aop" xmlns:tx="http://www.springframework.org/schema/tx" xsi:schemaLocation="http://www.springframework.org/schema/beans http://www.springframework.org/schema/beans/spring-beans-3.0.xsd http://www.springframework.org/schema/context http://www.springframework.org/schema/context/spring-context-3.0.xsd http://www.springframework.org/schema/tx http://www.springframework.org/schema/tx/spring-tx-3.0.xsd http://www.springframework.org/schema/aop http://www.springframework.org/schema/aop/spring-aop-3.0.xsd"> <bean id="xingoo" class="com.spring.test.chap44.Instrumentalist"/> <bean id="audience" class="com.spring.test.chap44.Audience" /> <aop:aspectj-autoproxy proxy-target-class="true"/> </beans>
执行结果如下:
turnOffCellphones() takeSeats() __________ perform ___________ applaud()
时间: 2024-10-16 21:13:58