浅谈Spring（四）AOP实例

来源：互联网发布：linux 多进程例子编辑：程序博客网时间：2024/06/06 01:01

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。

0 0