JDKProxy(JDK代理模式)

public interface UserDao {
    public void save();

    public void update();

    public void delete();

    public void find();
}

实现接口类

public class UserDaoImpl implements UserDao {
    public void save() {
        System.out.println("保存用户...");
    }

    public void update() {
        System.out.println("修改用户...");
    }

    public void delete() {
        System.out.println("删除用户...");
    }

    public void find() {
        System.out.println("查询用户...");
    }
}

创建代理类

public class MyJdkProxy implements InvocationHandler{
    private UserDao userDao;

    public MyJdkProxy(UserDao userDao){
        this.userDao = userDao;
    }

    public Object createProxy(){
        Object proxy = Proxy.newProxyInstance(userDao.getClass().getClassLoader(),userDao.getClass().getInterfaces(),this);
        return proxy;
    }

    public Object invoke(Object proxy, Method method, Object[] args) throws Throwable {
        if("save".equals(method.getName())){
            System.out.println("权限校验...");
            return method.invoke(userDao,args);
        }
        return method.invoke(userDao,args);
    }
}

测试代理

public class SpringDemo1 {
    @Test
    public void demo1(){
        UserDao userDao = new UserDaoImpl();

        UserDao proxy = (UserDao)new MyJdkProxy(userDao).createProxy();
        proxy.save();
        proxy.update();
        proxy.delete();
        proxy.find();
    }
}