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浅谈Spring(四)AOP实例
在《浅谈Spring(三)AOP原理》中我详细的介绍了AOP的基本概念和实现原理,这里给出代码示例。
一、XML方式
1. TestAspect:切面类
package com.spring.aop; import org.aspectj.lang.JoinPoint; import org.aspectj.lang.ProceedingJoinPoint; public class TestAspect { public void doAfter(JoinPoint jp) { System.out.println("log Ending method: " + jp.getTarget().getClass().getName() + "." + jp.getSignature().getName()); } public Object doAround(ProceedingJoinPoint pjp) throws Throwable { long time = System.currentTimeMillis(); Object retVal = pjp.proceed(); time = System.currentTimeMillis() - time; System.out.println("process time: " + time + " ms"); return retVal; } public void doBefore(JoinPoint jp) { System.out.println("log Begining method: " + jp.getTarget().getClass().getName() + "." + jp.getSignature().getName()); } public void doThrowing(JoinPoint jp, Throwable ex) { System.out.println("method " + jp.getTarget().getClass().getName() + "." + jp.getSignature().getName() + " throw exception"); System.out.println(ex.getMessage()); } }
2. AServiceImpl:目标对象
package com.spring.service; // 使用jdk动态代理 public class AServiceImpl implements AService { public void barA() { System.out.println("AServiceImpl.barA()"); } public void fooA(String _msg) { System.out.println("AServiceImpl.fooA(msg:" + _msg + ")"); } }
3. BServiceImpl:目标对象
package com.spring.service; // 使用cglib public class BServiceImpl { public void barB(String _msg, int _type) { System.out.println("BServiceImpl.barB(msg:" + _msg + " type:" + _type + ")"); if (_type == 1) throw new IllegalArgumentException("测试异常"); } public void fooB() { System.out.println("BServiceImpl.fooB()"); } }
4. ApplicationContext:Spring配置文件
<?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:aop="http://www.springframework.org/schema/aop" xmlns:context="http://www.springframework.org/schema/context" xmlns:tx="http://www.springframework.org/schema/tx" xsi:schemaLocation="http://www.springframework.org/schema/beans http://www.springframework.org/schema/beans/spring-beans-3.1.xsd http://www.springframework.org/schema/aop http://www.springframework.org/schema/aop/spring-aop-3.1.xsd http://www.springframework.org/schema/context http://www.springframework.org/schema/context/spring-context-3.1.xsd http://www.springframework.org/schema/tx http://www.springframework.org/schema/tx/spring-tx-3.1.xsd"> <aop:config> <aop:aspect id="TestAspect" ref="aspectBean"> <!--配置com.spring.service包下所有类或接口的所有方法--> <aop:pointcut id="businessService" expression="execution(* com.spring.service.*.*(..))" /> <aop:before pointcut-ref="businessService" method="doBefore"/> <aop:after pointcut-ref="businessService" method="doAfter"/> <aop:around pointcut-ref="businessService" method="doAround"/> <aop:after-throwing pointcut-ref="businessService" method="doThrowing" throwing="ex"/> </aop:aspect> </aop:config> <bean id="aspectBean" class="com.spring.aop.TestAspect" /> <bean id="aService" class="com.spring.service.AServiceImpl"></bean> <bean id="bService" class="com.spring.service.BServiceImpl"></bean> </beans>
二、注解(Annotation)方式
1. TestAnnotationAspect
package com.spring.aop; import org.aspectj.lang.ProceedingJoinPoint; import org.aspectj.lang.annotation.After; import org.aspectj.lang.annotation.AfterReturning; import org.aspectj.lang.annotation.AfterThrowing; import org.aspectj.lang.annotation.Around; import org.aspectj.lang.annotation.Aspect; import org.aspectj.lang.annotation.Before; import org.aspectj.lang.annotation.Pointcut; @Aspect public class TestAnnotationAspect { @Pointcut("execution(* com.spring.service.*.*(..))") private void pointCutMethod() { } //声明前置通知 @Before("pointCutMethod()") public void doBefore() { System.out.println("前置通知"); } //声明后置通知 @AfterReturning(pointcut = "pointCutMethod()", returning = "result") public void doAfterReturning(String result) { System.out.println("后置通知"); System.out.println("---" + result + "---"); } //声明例外通知 @AfterThrowing(pointcut = "pointCutMethod()", throwing = "e") public void doAfterThrowing(Exception e) { System.out.println("例外通知"); System.out.println(e.getMessage()); } //声明最终通知 @After("pointCutMethod()") public void doAfter() { System.out.println("最终通知"); } //声明环绕通知 @Around("pointCutMethod()") public Object doAround(ProceedingJoinPoint pjp) throws Throwable { System.out.println("进入方法---环绕通知"); Object o = pjp.proceed(); System.out.println("退出方法---环绕通知"); return o; } }
2. ApplicationContext:Spring配置文件
<?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:aop="http://www.springframework.org/schema/aop" xmlns:context="http://www.springframework.org/schema/context" xmlns:tx="http://www.springframework.org/schema/tx" xsi:schemaLocation="http://www.springframework.org/schema/beans http://www.springframework.org/schema/beans/spring-beans-3.1.xsd http://www.springframework.org/schema/aop http://www.springframework.org/schema/aop/spring-aop-3.1.xsd http://www.springframework.org/schema/context http://www.springframework.org/schema/context/spring-context-3.1.xsd http://www.springframework.org/schema/tx http://www.springframework.org/schema/tx/spring-tx-3.1.xsd"> <aop:aspectj-autoproxy></aop:aspectj-autoproxy> <bean class="org.springframework.aop.aspectj.annotation.AnnotationAwareAspectJAutoProxyCreator" /> <bean id="aspectBean" class="com.spring.aop.TestAnnotationAspect" /> <bean id="aService" class="com.spring.service.AServiceImpl"></bean> <bean id="bService" class="com.spring.service.BServiceImpl"></bean> </beans>
补充:
任何通知(Advice)方法可以将第一个参数定义为 org.aspectj.lang.JoinPoint类型。JoinPoint接口提供了一系列有用的方法, 比如 getArgs() (返回方法参数)、getThis() (返回代理对象)、getTarget() (返回目标)、getSignature() (返回正在被通知的方法相关信息)和 toString() (打印出正在被通知的方法的有用信息。
其中getSignature()返回的Signature对象可强制转换为MethodSignature,其功能非常强大,能获取包括参数名称在内的一切方法信息。
三、总结
通过详细的讲解和具体的实例,希望给大家呈现一个完整的AOP的初级教程。
浅谈Spring(四)AOP实例
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