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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