java代理模式（静态代理、动态代理、cglib代理）

public interface ITeacherDao {
	void teach(); // 授课的方法
}

public class TeacherDao implements ITeacherDao {
	@Override
	public void teach() {
		System.out.println("一键三连");
	}
}

public class TeacherDaoProxy implements ITeacherDao {
	private ITeacherDao target; //通过接口聚合目标对象
	public TeacherDaoProxy(ITeacherDao target) {
		this.target = target;
	}
	@Override
	public void teach() { //重写接口
		System.out.println("静态代理开始");
		target.teach();
		System.out.println("静态代理结束");
	}
}

public class Client {
	public static void main(String[] args) {
		//创建被代理对象
		TeacherDao teacherDao = new TeacherDao();
		//创建代理对象, 同时将被代理对象传递给代理对象
		TeacherDaoProxy teacherDaoProxy = new TeacherDaoProxy(teacherDao);
		//通过代理对象，调用到被代理对象的方法
		teacherDaoProxy.teach();
	}
}

static Object newProxyInstance(ClassLoader loader, Class<?>[] interfaces,InvocationHandler h )

public interface ITeacherDao {
	void teach();
	void tesst(String name);
}

public class TeacherDao implements ITeacherDao {
	@Override
	public void teach() {
		System.out.println("一键三连");
	}
	@Override
	public void tesst(String name) {
		System.out.println("传参测试：" + name);
	}
}

public class ProxyFactory {
	//维护一个目标对象 , Object
	private Object target;
	//构造器 ， 对target 进行初始化
	public ProxyFactory(Object target) {
		this.target = target;
	}
	//动态生成一个代理对象
	public Object getProxyInstance() {
		return Proxy.newProxyInstance(target.getClass().getClassLoader(),
				target.getClass().getInterfaces(),
				new InvocationHandler() { //匿名类重写invoke方法
					@Override
					public Object invoke(Object proxy, Method method, Object[] args) throws Throwable {
						System.out.println("动态代理开始");
						Object returnVal = method.invoke(target, args);//反射机制调用目标对象的方法
						System.out.println("动态代理结束");
						return returnVal;
					}
				});
	}
}

public class Client {
	public static void main(String[] args) {
		//创建目标对象
		ITeacherDao target = new TeacherDao();
		//创建代理对象
		ITeacherDao proxyInstance = (ITeacherDao)new ProxyFactory(target).getProxyInstance();
		//内存中动态生成了代理对象
		System.out.println(proxyInstance.getClass());
		//通过代理对象，调用目标对象的方法
		proxyInstance.teach();
		proxyInstance.tesst("一键三连");
	}
}

public class TeacherDao {
	public String teach() {
		System.out.println("一键三连");
		return "好";
	}
}

public class ProxyFactory implements MethodInterceptor {
	//目标对象
	private Object target;
	public ProxyFactory(Object target) {
		this.target = target;
	}
	//返回target对象的代理对象
	public Object getProxyInstance() {
		//创建一个工具类
		Enhancer enhancer = new Enhancer();
		//设置父类
		enhancer.setSuperclass(target.getClass());
		//设置回调函数
		enhancer.setCallback(this);
		//创建子类对象，即代理对象
		return enhancer.create();
	}
	//重写intercept方法，会调用目标对象的方法
	@Override
	public Object intercept(Object arg0, Method method, Object[] args, MethodProxy arg3) throws Throwable {
		System.out.println("Cglib代理开始");
		Object returnVal = method.invoke(target, args);
		System.out.println("Cglib代理结束");
		return returnVal;
	}
}

public class Client {
	public static void main(String[] args) {
		//创建目标对象
		TeacherDao target = new TeacherDao();
		//获取到代理对象，并且将目标对象传递给代理对象
		TeacherDao proxyInstance = (TeacherDao)new ProxyFactory(target).getProxyInstance();
		//执行代理对象的方法，触发intecept 方法，从而实现对目标对象的调用
		proxyInstance.teach();
		System.out.println(res);
	}
}