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
实例如下：
（1）：实现类：
package com.jiangfeng.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()----------");
}
}
（2）：
package com.jiangfeng.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()---------------");
}
}
（3）测试：
package com.jiangfeng.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);
}
}
（4）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: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.jiangfeng.spring.SecurityHandler"/>
<bean id="userManager" class="com.jiangfeng.spring.UserManagerImpl"/>
<aop:config>
<aop:aspect id="security" ref="securityHandler">
<aop:pointcut id="allAddMethod" expression="execution(* com.jiangfeng.spring.UserManagerImpl.add*(..))"/>
<aop:before method="checkSecurity" pointcut-ref="allAddMethod"/>
</aop:aspect>
</aop:config>
</beans>
输出结果：
2009-10-22 01:04:55,687 INFO [org.springframework.core.CollectionFactory] - JDK 1.4+ collections available
2009-10-22 01:04:55,750 INFO [org.springframework.beans.factory.xml.XmlBeanDefinitionReader] - Loading XML bean definitions from class path resource [applicationContext.xml]
2009-10-22 01:04:56,046 INFO [org.springframework.context.support.ClassPathXmlApplicationContext] - Bean factory for application context [org.springframework.context.support.ClassPathXmlApplicationContext;hashCode=10748354]: org.springframework.beans.factory.support.DefaultListableBeanFactory defining beans [securityHandler,userManager,org.springframework.aop.config.internalAutoProxyCreator,allAddMethod,org.springframework.aop.aspectj.AspectJPointcutAdvisor]; root of BeanFactory hierarchy
2009-10-22 01:04:56,062 INFO [org.springframework.context.support.ClassPathXmlApplicationContext] - 5 beans defined in application context [org.springframework.context.support.ClassPathXmlApplicationContext;hashCode=10748354]
2009-10-22 01:04:56,078 INFO [org.springframework.aop.framework.DefaultAopProxyFactory] - CGLIB2 available: proxyTargetClass feature enabled
2009-10-22 01:04:56,140 INFO [org.springframework.context.support.ClassPathXmlApplicationContext] - Bean 'org.springframework.aop.config.internalAutoProxyCreator' is not eligible for getting processed by all BeanPostProcessors (for example: not eligible for auto-proxying)
2009-10-22 01:04:56,140 INFO [org.springframework.context.support.ClassPathXmlApplicationContext] - Unable to locate MessageSource with name 'messageSource': using default [org.springframework.context.support.DelegatingMessageSource@15a0305]
2009-10-22 01:04:56,140 INFO [org.springframework.context.support.ClassPathXmlApplicationContext] - Unable to locate ApplicationEventMulticaster with name 'applicationEventMulticaster': using default [org.springframework.context.event.SimpleApplicationEventMulticaster@17653ae]
2009-10-22 01:04:56,156 INFO [org.springframework.beans.factory.support.DefaultListableBeanFactory] - Pre-instantiating singletons in factory [org.springframework.beans.factory.support.DefaultListableBeanFactory defining beans [securityHandler,userManager,org.springframework.aop.config.internalAutoProxyCreator,allAddMethod,org.springframework.aop.aspectj.AspectJPointcutAdvisor]; root of BeanFactory hierarchy]
张三
123
addUser
----------checkSecurity()---------------
-------UserManagerImpl.addUser()----------