代理模式Proxy

Posted 2022-01-08 ocean123123

public class MainActivity extends AppCompatActivity 

    TextView textView;
    Button button;
    protected void onCreate(Bundle savedInstanceState) 
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);
        textView = findViewById(R.id.text);
        button = findViewById(R.id.button);
        ProxySubject subject = new ProxySubject(new RealSubject());//客户端
        subject.visit();

    
    public interface Subject 
        void visit();
    
    public  class RealSubject implements Subject 

        private String name = "byhieg";
        @Override
        public void visit() 
            System.out.println(name);
        
    
    public  class ProxySubject implements Subject

        private Subject subject;

        public ProxySubject(Subject subject) 
            this.subject = subject;
        

        @Override
        public void visit() 
            subject.visit();
        
    
    

静态代理

public class MainActivity extends AppCompatActivity 

    TextView textView;
    Button button;
    protected void onCreate(Bundle savedInstanceState) 
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);
        textView = findViewById(R.id.text);
        button = findViewById(R.id.button);
        Subject realSubject = new RealSubject();
        DynamicProxy proxy = new DynamicProxy(realSubject);
        ClassLoader classLoader = realSubject.getClass().getClassLoader();
        Subject subject = (Subject) Proxy.newProxyInstance(classLoader, new  Class[]Subject.class, proxy);
        subject.visit();

    
    public interface Subject 
        void visit();
    
    public  class RealSubject implements Subject 

        private String name = "byhieg";
        @Override
        public void visit() 
            System.out.println(name);
        
    
    public class DynamicProxy implements InvocationHandler 
        private Object object;
        public DynamicProxy(Object object) 
            this.object = object;
        

        @Override
        public Object invoke(Object proxy, Method method, Object[] args) throws Throwable 
            Object result = method.invoke(object, args);
            return result;
        
    
    

动态代理

创建动态代理的对象，需要借助Proxy.newProxyInstance。该方法的三个参数分别是：
ClassLoader loader表示当前使用到的appClassloader。
Class<?>[] interfaces表示目标对象实现的一组接口。
InvocationHandler h表示当前的InvocationHandler实现实例对象。