基于JDK的实现可配置的AOP框架

上一篇已经写了基于JDK的动态代理的小例子，JDK动态代理必须有接口，才能使用，但是实际情况中没有接口该怎么办呢，就得用到cglib了。Spring AOP就是基于这两种代理模式的。可任意切换，也可以强制使用cglib的代理。

此篇主要是写JDK的动态代理，把上一篇的改造成一个小型的mini框架。



首先写个接口

package org.jdkTest;

public interface Hello {
	public void catHello();
}

package org.aop;

import java.lang.reflect.Method;

public interface Advice {
	public void before(Method method);
	public void after(Method method);
}

package org.aop;

import java.lang.reflect.Method;

public class MyAdvice implements Advice{

	public void after(Method method) {
		// TODO Auto-generated method stub
		System.out.println("--------------end----------");		
	}

	public void before(Method method) {
		// TODO Auto-generated method stub
		System.out.println("----------------start----------");
	}
}

package org.aop;

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

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

package org.aop;

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

public class ProxyFactoryBean {
	private Advice advice;
	private Object target;
	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(), 
				target.getClass().getInterfaces(), 
				new InvocationHandler(){
					@Override
					public Object invoke(Object proxy, Method method,
							Object[] args) throws Throwable {
						advice.before(method);
						Object result=method.invoke(target, args);
						advice.after(method);
						return result;
					}
					
				});
		return proxy;
	}
}

package org.aop;

import java.io.InputStream;
import java.util.Collection;

import com.sun.org.apache.bcel.internal.generic.NEW;

public class AopTest {
	public static void main(String[] args) {
		InputStream ips=AopTest.class.getResourceAsStream("config.properties");
		Object bean=new BeanFactory(ips).getBean("three");
		System.out.println(bean.getClass().getName());
		System.out.println(bean.toString());
	
	}
}

同一个包里面写一个配置文件 config.properties

three=org.aop.ProxyFactoryBean
three.advice=org.aop.MyAdvice
three.target=org.jdkTest.Hello