spring aop实例讲解_Spring Framework

2022-09-22 16:48:10 浏览数 (1)

大家好,又见面了,我是你们的朋友全栈君。

在上篇博文中,我向大家介绍了Aop重要概念和教程,这回给出代码示例。

一、XML方式

1. TestAspect:切面类

代码语言:javascript复制
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

代码语言:javascript复制
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

代码语言:javascript复制
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

代码语言:javascript复制
<?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

代码语言:javascript复制
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

代码语言:javascript复制
<?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>

关于切入点表达式,大家需要好好练习才能深入理解其中含义。即使看的懂,但是写起来却非常麻烦,并没有想象中那么简单。

最后,再告诉大家:

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。

============友情链接============

Spring Aop详尽教程 http://blog.csdn.net/wangpeng047/article/details/8556800

发布者:全栈程序员栈长,转载请注明出处:https://javaforall.cn/169620.html原文链接:https://javaforall.cn

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