56_实现类似spring的可配置的AOP框架

》 config.properties  配置文件   key=类名

》 BeanFactory  Bean工厂，负责得到bean  getBean(“xxx”)

》ProxyBeanFactory 产生代理的工厂  getProxy(Object target,Advice advice);

》AopFrameworkTest 测试类

思路:

getBean（”xxx”）

xxx=ProxyBeanFactory 时，返回代理类对象

xxx=其他类时，直接返回该类对象

• config.properties

#xxx=java.util.ArrayList
xxx=com.itcast.day3.aopframework.ProxyBeanFactory
xxx.advice=com.itcast.day3.MyAdvice
xxx.target=java.util.ArrayList

• BeanFactory

package com.itcast.day3.aopframework;

import java.io.IOException;
import java.io.InputStream;
import java.util.Properties;

import com.itcast.day3.Advice;

public class BeanFactory {
    private Properties props=new Properties();
    
    public BeanFactory(InputStream ips){
        try {
            props.load(ips);
        } catch (IOException e) {
            // TODO Auto-generated catch block
            e.printStackTrace();
        }
    }
    
   //bean工厂 
    public Object getBean(String name){
        Object bean=null;
         try {
            bean=Class.forName(props.getProperty(name)).newInstance();
             if(bean instanceof ProxyBeanFactory){
                 Object proxy=null;
                 ProxyBeanFactory proxyFactoryBean=(ProxyBeanFactory)bean;
                 Advice advice = (Advice)Class.forName(props.getProperty(name+".advice")).newInstance();
                 Object target = Class.forName(props.getProperty(name+".target").newInstance());
                 proxyFactoryBean.setAdvice(advice);
                 proxyFactoryBean.setTarget(target);
                 proxy=proxyFactoryBean.getProxy();
                 return proxy;
             }
        } catch (Exception e) {
            e.printStackTrace();
        } 
        return bean;
    }
    

}

• ProxyBeanFactory

 

package com.itcast.day3.aopframework;

import java.lang.reflect.InvocationHandler;
import java.lang.reflect.Method;
import java.lang.reflect.Proxy;

import com.itcast.day3.Advice;

public class ProxyBeanFactory {
    private Advice advice;//系统功能的封装，一般都有一个接口
    private Object target;//目标类 
    public Advice getAdvice() {
        return advice;
    }
    public void setAdvice(Advice advice) {
        this.advice = advice;
    }
    public Object getTarget() {
        return target;
    }
    public void setTarget(Object target) {
        this.target = target;
    }
    public Object getProxy() {
        Object proxy = Proxy.newProxyInstance(
                target.getClass().getClassLoader(), //目标类的类加载器
                target.getClass().getInterfaces(), //目标类实现的接口
                new InvocationHandler(){//匿名内部类
                    @Override
                    public Object invoke(Object proxy, Method method,
                            Object[] args) throws Throwable {
                        advice.beforeMethod(method);
                        Object reVal=method.invoke(target, args);//反射方式调用目标类的方法
                        advice.afterMethod(method);
                        return reVal;
                    }
                }
            );
        return proxy;
    }
    
    
}

• AopFrameworkTest

package com.itcast.day3.aopframework;

import java.io.InputStream;
import java.lang.reflect.Type;
import java.util.ArrayList;
import java.util.Collection;

public class AopFrameworkTest {
    public static void main(String[] args) throws Exception {
        InputStream ips=AopFrameworkTest.class.getResourceAsStream("config.properties");
        Object bean=new BeanFactory(ips).getBean("xxx");
        
        if(bean instanceof ArrayList){
            Collection collection=((Collection)bean);
            collection.add("123");
            for(Object obj:collection){
                System.out.println(obj);
            }
        }else{
            System.out.println("返回的是代理类: "+bean.getClass().getName()+" 的实例");
            ((Collection)bean).clear();
        }

    }
}