代理模式

1、目的

为其他对象提供一种代理以控制对这个对象的访问

2、分类

静态代理和动态代理

静态代理

简单示例：

public interface IUser {
	void buy();
}
public class User implements IUser{

	@Override
	public void buy() {
		System.out.println("买东西");
	}
}

public class UserProxy implements IUser{
	IUser user ;

	public UserProxy(IUser user) {
		this.user = user;
	}
	@Override
	public void buy() {
		System.out.println("机器人去");
		user.buy();
		System.out.println("机器人买回来");
	}
}

动态代理

简单示例：

public class DynamicUserProxy implements InvocationHandler{
	private Object object;
	public DynamicUserProxy(Object object) {
		this.object = object;
	}
	@Override
	public Object invoke(Object proxy, Method method, Object[] args) throws Throwable {
		System.out.println("处理前");
		Object obj = method.invoke(object, args);
		System.out.println("处理后");
		return obj;
	}
}

public class Test {
	public static void main(String[] args) {
		IUser user = new User();
		System.out.println("---------代理前---------");
		user.buy();
		System.out.println("---------代理后---------");
		IUser proxyUser = (IUser) Proxy.newProxyInstance(IUser.class.getClassLoader(),
				new Class[] {IUser.class}, new DynamicUserProxy(user));
		
		proxyUser.buy();
	}
}