Spring aop 简单总结

先用jdk，cglib模拟下：

使用JDK动态代理

//当目标类实现了接口，我们可以使用jdk的Proxy来生成代理对象。

 

package cn.zyj15.aop;

import java.lang.reflect.InvocationHandler;
import java.lang.reflect.Method;
import java.lang.reflect.Proxy;
import cn.zyj15.service.impl.PersonServiceBean;
/**
 * 
 * @author Administrator
 *实现InvocationHandler接口的即为代理，记实现invoke方法
 */
public class JDKProxyFactory implements InvocationHandler {
    private Object targetObject;
	
	public Object createProxyIntance(Object targetObject){
		this.targetObject = targetObject;
		//从newProxyInstance方法看出用jdk实现代理必须实现接口
		/*
		* 第一个参数设置代码使用的类装载器,一般采用跟目标类相同的类装载器
		* 第二个参数设置代理类实现的接口
		* 第三个参数设置回调对象,当代理对象的方法被调用时,会委派给该参数指定对象的invoke方法
		*/
		return Proxy.newProxyInstance(this.targetObject.getClass().getClassLoader(), 
				this.targetObject.getClass().getInterfaces(), this);
	}
	
	@Override
	public Object invoke(Object proxy, Method method, Object[] args)
			throws Throwable {//环绕通知
		PersonServiceBean bean = (PersonServiceBean) this.targetObject;
		Object result = null; 
		if(bean.getUser()!=null){
			//..... advice()-->前置通知
			try {
				result = method.invoke(targetObject, args);//把方法调用委派给目标对象
				// afteradvice() -->后置通知
			} catch (RuntimeException e) {
				//exceptionadvice()--> 例外通知
			}finally{
				//finallyadvice(); -->最终通知
			}
		}else {
			System.out.println("没有权限！");
		}
		return result;
	}

}

 

 

package junit.test15;

import static org.junit.Assert.*;
import org.junit.Test;
import cn.zyj15.aop.JDKProxyFactory;
import cn.zyj15.service.PersonService;
import cn.zyj15.service.impl.PersonServiceBean;

public class AOPTest {

	@Test
	public void jdktest() {
		JDKProxyFactory factory = new JDKProxyFactory();
		//必须用接口
		PersonService service = (PersonService) factory.createProxyIntance(new PersonServiceBean(null));
		service.save("888");
	}

}

 

使用CGLIB生成代理

//CGLIB可以生成目标类的子类，并重写父类非final修饰符的方法。

 

package cn.zyj16.aop;

import java.lang.reflect.Method;
import cn.zyj16.service.impl.PersonServiceBean;
import net.sf.cglib.proxy.Enhancer;
import net.sf.cglib.proxy.MethodInterceptor;
import net.sf.cglib.proxy.MethodProxy;

public class CGlibProxyFactory implements MethodInterceptor{
	private Object targetObject;//代理的目标对象	
	
	public Object createProxyIntance(Object targetObject){
		this.targetObject = targetObject;
		Enhancer enhancer = new Enhancer();//该类用于生成代理对象
		enhancer.setSuperclass(this.targetObject.getClass());//设置代理类的父类。CGLIB可以生成目标类的子类，并重写父类非final修饰符的方法。
		enhancer.setCallback(this);//设置回调方法
		return enhancer.create();//创建代理对象
	}

	public Object intercept(Object proxy, Method method, Object[] args,
			MethodProxy  methodProxy) throws Throwable {
		PersonServiceBean bean = (PersonServiceBean) this.targetObject;
		Object result = null;
		if(bean.getUser()!=null){
			result = methodProxy.invoke(targetObject, args);
		}
		return result;
	}
}

 

 

package junit.test16;

import static org.junit.Assert.*;

import org.junit.Test;


import cn.zyj16.service.PersonService;
import cn.zyj16.service.impl.PersonServiceBean;
import cn.zyj16.aop.CGlibProxyFactory;

public class AOPTest {

	@Test public void cglibTest2(){
		CGlibProxyFactory factory = new CGlibProxyFactory();
		//此事创建的代理对象是PersonServiceBean的子类！
		PersonServiceBean service = (PersonServiceBean) factory.createProxyIntance(new PersonServiceBean("xxx"));
		service.save("999");
	}
}

 

 

 

AOP中的概念

Aspect(切面):指横切性关注点的抽象即为切面,它与类相似,只是两者的关注点不一样,类是对物体特征的抽象,而切面横切性关注点的抽象.

joinpoint(连接点):所谓连接点是指那些被拦截到的点。在spring中,这些点指的是方法,因为spring只支持方法类型的连接点,实际上joinpoint还可以是field或类构造器)

Pointcut(切入点):所谓切入点是指我们要对那些joinpoint进行拦截的定义.

Advice(通知):所谓通知是指拦截到joinpoint之后所要做的事情就是通知.通知分为前置通知,后置通知,异常通知,最终通知,环绕通知

Target(目标对象):代理的目标对象

Weave(织入):指将aspects应用到target对象并导致proxy对象创建的过程称为织入.

Introduction(引入):在不修改类代码的前提下, Introduction可以在运行期为类动态地添加一些方法或Field.

 

 

使用Spring进行面向切面（AOP）编程

要进行AOP编程，首先我们要在spring的配置文件中引入aop命名空间：

<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"

       xsi:schemaLocation="http://www.springframework.org/schema/beans

           http://www.springframework.org/schema/beans/spring-beans-2.5.xsd

           http://www.springframework.org/schema/aop                                  http://www.springframework.org/schema/aop/spring-aop-2.5.xsd">

</beans>

 

Spring提供了两种切面声明方式，实际工作中我们可以选用其中一种：

基于XML配置方式声明切面。

基于注解方式声明切面。

基于注解方式声明切面

首先启动对@AspectJ注解的支持(蓝色部分)：

 

<?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:context="http://www.springframework.org/schema/context" 

       xmlns:aop="http://www.springframework.org/schema/aop"      

       xsi:schemaLocation="http://www.springframework.org/schema/beans

           http://www.springframework.org/schema/beans/spring-beans-2.5.xsd

           http://www.springframework.org/schema/context http://www.springframework.org/schema/context/spring-context-2.5.xsd

           http://www.springframework.org/schema/aop http://www.springframework.org/schema/aop/spring-aop-2.5.xsd">

        <aop:aspectj-autoproxy/> 

        <bean id="myInterceptor" class="cn.zyj17.service.MyInterceptor"/>

        <bean id="personService" class="cn.zyj17.service.impl.PersonServiceBean"></bean>

</beans>

 

 

 

 

package cn.zyj17.service;

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;
/**
 * 切面
 *
 */
@Aspect
public class MyInterceptor {
	@Pointcut("execution (* cn.zyj17.service.impl.PersonServiceBean.*(..))")
	private void anyMethod() {}//声明一个切入点
	
	@Before("anyMethod() && args(name)")
	public void doAccessCheck(String name) {
		System.out.println("前置通知:"+ name);
	}
	@AfterReturning(pointcut="anyMethod()",returning="result")
	public void doAfterReturning(String result) {
		System.out.println("后置通知:"+ result);
	}
	@After("anyMethod()")
	public void doAfter() {
		System.out.println("最终通知");
	}
	@AfterThrowing(pointcut="anyMethod()",throwing="e")
	public void doAfterThrowing(Exception e) {
		System.out.println("例外通知:"+ e);
	}
	
	@Around("anyMethod()")
	public Object doBasicProfiling(ProceedingJoinPoint pjp) throws Throwable {
		//if(){//判断用户是否在权限
		System.out.println("进入方法");
		Object result = pjp.proceed();
		System.out.println("退出方法");
		//}
		return result;
	}
	
}

 

 

 

package junit.test17;

import org.junit.BeforeClass;
import org.junit.Test;
import org.springframework.context.ApplicationContext;
import org.springframework.context.support.ClassPathXmlApplicationContext;

import cn.zyj17.service.PersonService;

public class SpringAOPTest {

	@BeforeClass
	public static void setUpBeforeClass() throws Exception {
	}

	@Test public void interceptorTest(){
		ApplicationContext cxt = new ClassPathXmlApplicationContext("beans.xml");
		PersonService personService = (PersonService)cxt.getBean("personService");//接口
		personService.save("xx");
	}
}

 

 

基于基于XML配置方式声明切面

 

<?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:context="http://www.springframework.org/schema/context" 
       xmlns:aop="http://www.springframework.org/schema/aop"      
       xsi:schemaLocation="http://www.springframework.org/schema/beans
           http://www.springframework.org/schema/beans/spring-beans-2.5.xsd
           http://www.springframework.org/schema/context http://www.springframework.org/schema/context/spring-context-2.5.xsd
           http://www.springframework.org/schema/aop http://www.springframework.org/schema/aop/spring-aop-2.5.xsd">
       <aop:aspectj-autoproxy/> 
        <bean id="personService" class="cn.zyj19.service.impl.PersonServiceBean"></bean>
        <bean id="aspetbean" class="cn.zyj19.service.MyInterceptor"/>
        <aop:config>
        	<aop:aspect id="asp" ref="aspetbean">
        		<aop:pointcut id="mycut" expression=" execution(* cn.zyj19.service..*.*(..))"/>
        		<aop:before pointcut-ref="mycut" method="doAccessCheck"/>
        		<aop:after-returning pointcut-ref="mycut" method="doAfterReturning"/>
			  	<aop:after-throwing pointcut-ref="mycut" method="doAfterThrowing"/>
			  	<aop:after pointcut-ref="mycut" method="doAfter"/>
			  	<aop:around pointcut-ref="mycut" method="doBasicProfiling"/>
        	</aop:aspect>
        </aop:config>
</beans>

 package cn.zyj19.service;

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;
/**
 * 切面
 *
 */
public class MyInterceptor {
	public void doAccessCheck() {
		System.out.println("前置通知");
	}

	public void doAfterReturning() {
		System.out.println("后置通知");
	}
	
	public void doAfter() {
		System.out.println("最终通知");
	}
	
	public void doAfterThrowing() {
		System.out.println("例外通知");
	}
	
	public Object doBasicProfiling(ProceedingJoinPoint pjp) throws Throwable {
		System.out.println("进入方法");
		Object result = pjp.proceed();
		System.out.println("退出方法");
		return result;
	}
}

 

 

package junit.test19;

import org.junit.BeforeClass;
import org.junit.Test;
import org.springframework.context.ApplicationContext;
import org.springframework.context.support.ClassPathXmlApplicationContext;

import cn.zyj19.service.PersonService;

public class SpringAOPTest {

	@BeforeClass
	public static void setUpBeforeClass() throws Exception {
	}

	@Test public void interceptorTest(){
		ApplicationContext cxt = new ClassPathXmlApplicationContext("beans.xml");
		PersonService personService = (PersonService)cxt.getBean("personService");
		personService.save("xx");
	}
}