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。
时间： 2024-10-25 09:16:55