利用代理模式实现日志功能

场景

实现一个类，该类实现了数学四则运算，实现日志功能，每次调用对应的运算时，输出相应的日志

基本功能接口

package com.javase.thread;

public interface Arithmetic {
	public int add( int i, int j );
	public int sub( int i, int j );
	public int mul( int i, int j );
	public int div( int i, int j );
}

接口的实现类

package com.javase.thread;

public class ArithmeticImp implements Arithmetic {
	@Override
	public int add(int i, int j) {
		// TODO Auto-generated method stub
		return i+j;
	}

	@Override
	public int sub(int i, int j) {
		// TODO Auto-generated method stub
		return i-j;
	}

	@Override
	public int mul(int i, int j) {
		// TODO Auto-generated method stub
		return i*j;
	}

	@Override
	public int div(int i, int j) {
		// TODO Auto-generated method stub
		return i/j;
	}

}

代理类输出日志

package com.javase.thread;

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

public class ArithmeticLoggingProxy {
	//要代理的对象
	private Arithmetic target;
	public ArithmeticLoggingProxy( Arithmetic arithmetic ) {
		this.target = arithmetic;
	}
	
	public Arithmetic getLoggingProxy() {
		Arithmetic proxy = null;
		//1.获取要代理对象的类加载器
		ClassLoader classLoader = target.getClass().getClassLoader();
		//2.代理对象的类型
		Class []  interfaces = new Class[] {Arithmetic.class};
		//3.当调用代理对象的方法是执行的代码
		InvocationHandler h = new InvocationHandler() {		
			@Override
			public Object invoke(Object proxy, Method method, Object[] args) throws Throwable {
				// TODO Auto-generated method stub
				System.out.println("正在执行的方法："+method.getName());
				Object result = method.invoke(target, args);
				System.out.println("结果为: "+result);
				return result;
			}
		};
		proxy = (Arithmetic) Proxy.newProxyInstance(classLoader, interfaces, h);
		return proxy;
	}
}

Main函数

package com.javase.thread;

public class Main {

	public static void main(String[] args) {
		Arithmetic proxy = new ArithmeticLoggingProxy(new ArithmeticImp()).getLoggingProxy();
		System.out.println(proxy.add(1, 2));
	}

}