代码参见dynamic-proxy-AOP2
基于配置文件的方式的好处在于所谓的分层.所以号称应该推荐使用这个方法
随便了.代码重新贴一次吧.
1.UserManager接口
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package com.zyl.proxy;
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public interface UserManager
{
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public void addUser(String name,String password);
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public void delUser(String id);
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public void modifyUser(int id, String name, String password);
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}
2.UserManagerImpl(UserManager的实现类)
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package com.zyl.proxy;
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public class UserManagerImpl implements UserManager
{
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public void addUser(String name, String password)
{
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//
添加日志/安全性检查
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//checksafe();
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//采用添加代理类的方法会如何?
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System.out.println("UserManagerImpl.addUser()123");
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}
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@Override
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public void delUser(String id)
{
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//
添加日志/安全性检查
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//checksafe();
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System.out.println("UserManagerImpl.delUser()");
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}
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@Override
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public void modifyUser(int id, String name, String password)
{
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//
添加日志/安全性检查
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//checksafe();
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System.out.println("UserManagerImpl.modifyUser()");
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}
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// private void checksafe(){
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// System.out.println("检查安全性的方法");
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// }
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}
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3.感觉应该叫切面的接口?
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package com.zyl.proxy;
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//切入点
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public interface MySecurityManager
{
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public void checkSafe();
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}
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4.实现
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package com.zyl.proxy;
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import org.aspectj.lang.annotation.Aspect;
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import org.aspectj.lang.annotation.Before;
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import org.aspectj.lang.annotation.Pointcut;
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public class MySecurityManagerImpl implements MySecurityManager
{
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public void checkSafe()
{
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System.out.println("checkSafe安全性检查");
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}
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}
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这里的切面的代码简化很多.只要写需要额外加入的方法即可.其他的声明放在配置文件中
5.client
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package com.zyl.ooxx;
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import org.springframework.beans.factory.BeanFactory;
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import org.springframework.context.support.ClassPathXmlApplicationContext;
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import com.zyl.proxy.UserManager;
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public class client
{
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public static void main(String[] args)
{
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//所有对象要从ioc中去取,所以之前这些对象要在xml中注册
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//通过配置文件初始化bean工厂
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BeanFactory factory =new ClassPathXmlApplicationContext("applicationContext.xml");
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//通过bean工厂得到UserManager
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UserManager usermanager=(UserManager)factory.getBean("userManagergb23122");
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usermanager.addUser("1", "password");
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System.out.println("------------");
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usermanager.delUser("1");
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}
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}
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其实认真看.这个和annotation方式的代码都一样啊.
就只有4.MySecurityManagerImpl代码的简化.和6.配置文件的改变
6.配置文件
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<?xml version="1.0" encoding="UTF-8"?>
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<beans xmlns="http://www.springframework.org/schema/beans"
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xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
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xmlns:context="http://www.springframework.org/schema/context"
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xmlns:tx="http://www.springframework.org/schema/tx"
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xmlns:aop="http://www.springframework.org/schema/aop"
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xsi:schemaLocation="http://www.springframework.org/schema/beans
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http://www.springframework.org/schema/beans/spring-beans-2.5.xsd
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http://www.springframework.org/schema/context
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http://www.springframework.org/schema/context/spring-context-2.5.xsd
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http://www.springframework.org/schema/aop
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http://www.springframework.org/schema/aop/spring-aop-2.5.xsd
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http://www.springframework.org/schema/tx
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http://www.springframework.org/schema/tx/spring-tx-2.5.xsd">
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<bean id="mySecurityManagerImp" class="com.zyl.proxy.MySecurityManagerImpl"/>
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<bean id="userManagergb23122" class="com.zyl.proxy.UserManagerImpl"/>
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<aop:config>
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<!-- 配置切面 -->
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<aop:aspect id="securityAspect" ref="mySecurityManagerImp">
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<!-- 描述切入点 -->
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<aop:pointcut id="allAddMethod13" expression="execution(* add*(..))"/> <!-- 切入点的什么,类似@Pointcut("execution(* add*(..))") 前一种方法中的这个写法 -->
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<!-- 描述advice -->
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<aop:before pointcut-ref="allAddMethod13" method="checkSafe"/><!-- 这个before标签说明是之前执行的. 注意id的对应.method就是新加入的方法的方法名了-->
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</aop:aspect>
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</aop:config>
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</beans>
这个..变化就很大了
具体看我的注释吧.
参看前一种方式.就很好理解了
小结:
spring对aop的支持
1.采用配置文件的方式
2.将切面,切入点,通知等定义在配置文件中
<aop:config>
<!-- 配置切面 -->
<aop:aspect id="securityAspect" ref="mySecurityManagerImp">
<!-- 描述切入点 -->
<aop:pointcut id="allAddMethod" expression="execution(* add*(..))"/>
<!-- 描述advice -->
<aop:before pointcut-ref="allAddMethod" method="checkSafe"/>
</aop:aspect>
</aop:config>
--------------------
p.s 我们可以得到切入点方法的信息(如addUser的方法名,传入参数的值)之前动态代理当时是怎么做的呢?
代码如下:
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public Object invoke(Object proxy, Method method, Object[] args)//args是传递过来的参数,比如name为张三
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throws Throwable
{
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//调用任何方法前都会前调用invoke方法,所以我们在invoke方法前放置需要调用的代码 如安全性检查/log日志等等添加的方法
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//这里还可以加入一些逻辑判断,是否加入安全性检查
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checksafe();
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System.out.println("方法名是"+method.getName());
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for(int i=0;i<args.length;i++)
{
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System.out.println("哈哈"+args[i]);
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}
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//临时添加方法调用结束
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//以下调用一般的方法
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Object result=null;
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try
{
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method.invoke(targetObj,args); //真正的调用对象的实现的方法(非添加的那些方法)
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}catch(Exception e)
{
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e.printStackTrace();
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}
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return result; //invoke方法需要返回一个对象.所以前面定义了一个Object result=null; 这里返回result
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}
配置文件的方式:我们可以通过方法名来判断是否添加切面的内容.可是如何取得切入点方法的方法名,传入参数这些值呢?(比如addUser("男人都是","帅哥")可以取得方法名:addUser,男人都是,帅哥等参数)
做法: 在通知中加入一个JoinPoint参数(大小写敏感),这个参数spring会自动传入,我们从JoinPoint中可以取得目标对象的相关信息,如参数,方法名等.
将切面实现类修改即可:
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package com.zyl.proxy;
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import org.aspectj.lang.JoinPoint;
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public class MySecurityManagerImpl
{
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public void checkSafe(JoinPoint joinpoint)
{
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Object[] args=joinpoint.getArgs();//得到参数
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for(int i=0;i<args.length;i++)
{
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System.out.println("参数是:"+args[i]);
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}
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System.out.println("方法名是:"+joinpoint.getSignature().getName());
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System.out.println("checkSafe安全性检查");
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}
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}
JointPoint自然会取得相应的信息.
题外话:
1.切面默认的情况下不需要接口(MySecurityManager接口其实可以不必存在);
2.对于目标对象(UserManagerImpl类),默认情况下必须实现接口(jdk动态代理需要接口).
如果不是用接口,我们要使用CGLIB库的支持才可以.