Spring学习-day09

动态代理：

package com.atguigu.spring.aop.helloworld;

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

public class ArithmeticCalculatorLoggingProxy {
	
	//要代理的对象
	private ArithmeticCalculator target;
	
	public ArithmeticCalculatorLoggingProxy(ArithmeticCalculator target) {
		this.target = target;
	}

	public ArithmeticCalculator  getLoggingProxy() {
		ArithmeticCalculator proxy = null;
		
		//代理对象由哪一个类加载器负责加载
		ClassLoader loader = target.getClass().getClassLoader();
		//代理对象的类型,即其中有哪些方法
		Class[] interfaces = new Class[]{ArithmeticCalculator.class};
		
		//当调用代理对象其中的方法时, 该执行的代码
		InvocationHandler h = new InvocationHandler() {
			/**
			 * proxy: 正在返回的那个代理对象, 一般情况下, 在 invoke 方法中都不使用该对象
			 * method: 正在被调用的方法
			 * args: 调用方法时, 传入的参数
			 */
			@Override
			public Object invoke(Object proxy, Method method, Object[] args) 
					throws Throwable {
				String methodName = method.getName();
				//日志
				System.out.println("The method " + methodName + " begins with " + Arrays.asList(args));
				//执行方法
				Object result = method.invoke(target, args);
				//日志
				System.out.println("The method " + methodName + " ends with " + result);
				return result;
			}
		};
		proxy = (ArithmeticCalculator) Proxy.newProxyInstance(loader, interfaces, h);
		
		return proxy;
	}
}

package com.atguigu.spring.aop.helloworld;

public class ArithmeticCalculatorImpl implements ArithmeticCalculator {

	@Override
	public int add(int i, int j) {
		
		int result = i + j;
		return result;
	}

	@Override
	public int sub(int i, int j) {
		
		int result = i - j;
		return result;
	}

	@Override
	public int mul(int i, int j) {
		
		int result = i * j;
		return result;
	}

	@Override
	public int div(int i, int j) {
		
		int result = i / j;
		return result;
	}

}

package com.atguigu.spring.aop.helloworld;

public interface ArithmeticCalculator {
	//加减乘除
	int add(int i, int j);
	int sub(int i, int j);
	
	int mul(int i, int j);
	int div(int i, int j);
}

package com.atguigu.spring.aop.helloworld;

public class Main {
	public static void main(String[] args) {
//		ArithmeticCalculatorImpl arithmeticCalculatorImpl = new ArithmeticCalculatorImpl();
		
		ArithmeticCalculator target = new ArithmeticCalculatorImpl();
		ArithmeticCalculator proxy = new ArithmeticCalculatorLoggingProxy(target).getLoggingProxy();
		
		int result = proxy.add(1, 2);
		System.out.println("-->" + result);
		
		result = proxy.div(4, 2);
		System.out.println("-->" + result);
	}
}