Java反射：實現接口並傳遞給另一個類

Question

我不確定這是否可以用Java，但我試圖實現一個在編譯時不可用的接口**並將它作爲一個對象傳遞給另一個類的界面。比方說，我有這樣的接口：

public interface MyInterface { 
    void onReceive(int i); 
} 

和其他類，如：

public void MyClass { 
    ArrayList<MyInterface> listenerList = new ArrayList<MyInterface>(); 

    public void add(MyInterface m) { 
     listenerList.add(m); 
    } 
} 

如果他們可以在編譯的時候，我會用他們喜歡的：

blah = new MyInterface() { 
    public void onReceive(int i) { 
     System.out.println("BLAH"); 
    } 
} 

MyClass mc = new MyClass(); 
myClass.add(blah); 

我想知道是否有一種方法可以編寫與上面相同的代碼，前兩個類只在運行時纔可用。

提前致謝！

**我試圖從Android的ROM使用框架庫，但它是在達爾維克字節碼，所以我不能用它進行編譯。

UPDATE：下面是我用來測試溶液一些示例代碼：

文件A/IIMSListener.java

// Excerpt from decompiled class 

public interface IIMSListener 
{ 
    void onReceive(int p0, int p1/*, IMSParameter p2*/); 
} 

文件A/IMSRemoteListenerStub.java

// Excerpt from decompiled class 

import java.util.concurrent.*; 
import java.util.*; 

public class IMSRemoteListenerStub 
{ 
    public List<IIMSListener> mListenerList = new CopyOnWriteArrayList<IIMSListener>(); 

    public boolean addListener(final IIMSListener iimsListener) { 
     if (iimsListener != null && !this.mListenerList.contains(iimsListener)) { 
      this.mListenerList.add(iimsListener); 
      return true; 
     } 
     return false; 
    } 

    public boolean removeListener(final IIMSListener iimsListener) { 
     if (iimsListener != null && this.mListenerList.contains(iimsListener)) { 
      this.mListenerList.remove(iimsListener); 
      return true; 
     } 
     return false; 
    } 
} 

文件b/test.java

impor t java.lang.reflect。 ; import java.util。;

public class test { 
    public static void main(String[] args) throws IllegalAccessException, 
               IllegalArgumentException, 
               InvocationTargetException, 
               NoSuchMethodException, 
               SecurityException, 
               ClassNotFoundException { 

    // Implement interface 
    Class<?> IIMSListener = Class.forName("IIMSListener"); 

    Object listenerInstance = Proxy.newProxyInstance(IIMSListener.getClassLoader(), new Class<?>[]{IIMSListener}, new InvocationHandler() { 
     @Override 
     public Object invoke(Object proxy, Method method, Object[] args) throws Throwable { 
     if(method.getName().equals("onReceive")){ 
      System.out.println("ARGS: " + (Integer)args[0] + ", " + (Integer)args[1]); 
      return 1; 
     } 
     else return -1; 
     } 
    }); 

    // Test 
    Method onReceive = listenerInstance.getClass().getDeclaredMethod("onReceive", new Class[] { int.class, int.class }); 
    onReceive.invoke(listenerInstance, new Object[] { 1, 2 }); 

    try { 
     // Pass to another class 
     Class IMSRemoteListenerStub = Class.forName("IMSRemoteListenerStub"); 
     Constructor ctor = IMSRemoteListenerStub.getConstructor(); 
     Object stubInstance = ctor.newInstance(new Object[] {}); 
     Method addListener = stubInstance.getClass().getDeclaredMethod("addListener", new Class[] { IIMSListener }); 
     addListener.invoke(stubInstance, new Object[] { listenerInstance }); 

     // Test 
     Field mListenerList = IMSRemoteListenerStub.getField("mListenerList"); 
     List<?> list = (List<?>)mListenerList.get(stubInstance); 
     onReceive.invoke(list.get(0), new Object[] { 3, 4 }); 
    } 
    catch (InstantiationException e) {} 
    catch (NoSuchFieldException e) {} 
    } 
} 

執行：

$ cd b 
$ CLASSPATH=".:../a" java test 
ARGS: 1, 2 
ARGS: 3, 4 

Answer 1

如果將是相同的接口，然後使用Dynamic Proxies

//Loading the class at runtime 
public static void main(String[] args) throws IllegalAccessException, IllegalArgumentException, InvocationTargetException, NoSuchMethodException, SecurityException, ClassNotFoundException { 
    Class<?> someInterface = Class.forName("SomeInterface"); 

    Object instance = Proxy.newProxyInstance(someInterface.getClassLoader(), new Class<?>[]{someInterface}, new InvocationHandler() { 

     @Override 
     public Object invoke(Object proxy, Method method, Object[] args) throws Throwable { 

      //Handle the invocations 
      if(method.getName().equals("someMethod")){ 
       return 1; 
      } 
      else return -1; 
     } 
    }); 
    System.out.println(instance.getClass().getDeclaredMethod("someMethod", (Class<?>[])null).invoke(instance, new Object[]{})); 
}