AOP4

spring对AOP的支持

1、如果目标对象实现了接口，默认情况下会采用JDK的动态代理实现AOP
2、如果目标对象实现了接口，可以强制使用CGLIB实现AOP
3、如果目标对象没有实现了接口，必须采用CGLIB库，spring会自动在JDK动态代理和CGLIB之间转换


如何强制使用CGLIB实现AOP？
* 添加CGLIB库，SPRING_HOME/cglib/*.jar
* 在spring配置文件中加入<aop:aspectj-autoproxy proxy-target-class="true"/>

JDK动态代理和CGLIB字节码生成的区别？
* JDK动态代理只能对实现了接口的类生成代理，而不能针对类
* CGLIB是针对类实现代理，主要是对指定的类生成一个子类，覆盖其中的方法
  因为是继承，所以该类或方法最好不要声明成final



applicationContext.xml

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

http://www.springframework.org/schema/beans/spring-beans-2.0.xsd
           http://www.springframework.org/schema/aop http://www.springframework.org/schema/aop/spring-aop-2.0.xsd
           http://www.springframework.org/schema/tx http://www.springframework.org/schema/tx/spring-tx-2.0.xsd">
	<!-- 
	<aop:aspectj-autoproxy proxy-target-class="true"/>
	 -->
	<bean id="securityHandler" class="com.bjsxt.spring.SecurityHandler"/>           
	
	<bean id="userManager" class="com.bjsxt.spring.UserManagerImpl"/>
	
	<aop:config>
		<aop:aspect id="security" ref="securityHandler">
			<aop:pointcut id="allAddMethod" expression="execution(* 

com.bjsxt.spring.UserManagerImpl.add*(..))"/>
			<aop:before method="checkSecurity" pointcut-ref="allAddMethod"/>
		</aop:aspect>
	</aop:config>	
</beans>

SecurityHandler.java

package com.bjsxt.spring;

import org.aspectj.lang.JoinPoint;

public class SecurityHandler {
	
	private void checkSecurity(JoinPoint joinPoint) {
		Object[] args = joinPoint.getArgs();
		for (int i=0; i<args.length; i++) {
			System.out.println(args[i]);
		}
		
		System.out.println(joinPoint.getSignature().getName());
		System.out.println("----------checkSecurity()---------------");
	}
	
}

UserManagerImpl.java

package com.bjsxt.spring;

public class UserManagerImpl { // implements UserManager {

	public void addUser(String username, String password) {
		System.out.println("-------UserManagerImpl.addUser()----------");
	}

	public void deleteUser(int id) {
		System.out.println("-------UserManagerImpl.deleteUser()----------");
	}

	public String findUserById(int id) {
		System.out.println("-------UserManagerImpl.findUserById()----------");
		return null;
	}

	public void modifyUser(int id, String username, String password) {
		System.out.println("-------UserManagerImpl.modifyUser()----------");
	}
	
//	private void checkSecurity() {
//		System.out.println("----------checkSecurity()---------------");
//	}
}

Client.java

package com.bjsxt.spring;

import org.springframework.beans.factory.BeanFactory;
import org.springframework.context.support.ClassPathXmlApplicationContext;

public class Client {

	public static void main(String[] args) {
		BeanFactory factory = new ClassPathXmlApplicationContext("applicationContext.xml");
		
		//UserManager userManager = (UserManager)factory.getBean("userManager");
		
		UserManagerImpl userManager = (UserManagerImpl)factory.getBean("userManager");
		userManager.addUser("张三", "123");
		//userManager.deleteUser(1);
	}
}