jdk动态代理技术demo（干货）

学习完jdk动态代理以后，写的demo。为了方便以后查阅，特将代码贴
到博客上，以后有时间再详细讲解

通知接口

package com.me.aop;

public interface IAdvice {
	void befor();
	void after();
}

通知实现类，完成日志打印

package com.me.aop;

public class LogAdvice implements IAdvice {

	@Override
	public void befor() {
		System.out.println("方法开始");
	}

	@Override
	public void after() {
		System.out.println("方法结束");
	}
	
}

代理实现方式有多种，例如jdk、cglib...

package com.me.aop;

public interface IProxyProvider {
	Object getProxyObj();
}

jdk实现

package com.me.aop;

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

public class JDKProxyImpl implements IProxyProvider {
	
	private IAdvice advice;
	private Object target;
	
	public JDKProxyImpl() {
	}
	public JDKProxyImpl(IAdvice IAdvice, Object target) {
		this.advice = IAdvice;
		this.target = target;
	}
	
	public IAdvice getAdvice() {
		return advice;
	}
	public void setAdvice(IAdvice advice) {
		this.advice = advice;
	}
	public Object getTarget() {
		return target;
	}
	public void setTarget(Object target) {
		this.target = target;
	}
	@Override
	public Object getProxyObj() {
		Object obj = Proxy.newProxyInstance(target.getClass().getClassLoader(), target.getClass().getInterfaces(), new InvocationHandler() {
			
			@Override
			public Object invoke(Object proxy, Method method, Object[] args)
					throws Throwable {
				if(advice != null){
					advice.befor();
				}
				Object  result = method.invoke(target, args);
				if(advice != null){
					advice.after();
				}
				return result;
			}
		});
		return obj;
	}

}

由于jdk动态代理要求代理的对象必须实现最少一个接口

package com.me.aop;

public interface Caculator {
	int substrct(int a,int b);
}

package com.me.aop;

public class CaculaterImpl implements Caculator {

	@Override
	public int substrct(int a, int b) {
		System.out.println("方法执行中.....");
		return a-b;
	}

}

客户端

package com.me.aop;


public class Client {
	public static void main(String[] args) {
		//测试jdk动态代理
		IAdvice  logAdvice = new LogAdvice();
		Caculator caculator = new CaculaterImpl();
		IProxyProvider proxyProvider = new JDKProxyImpl(logAdvice,caculator);
		Caculator caculatorProxy = (Caculator) proxyProvider.getProxyObj();
		System.out.println(caculatorProxy.substrct(3, 1));
	}
	
	
}

亲测可用！