java利用反射爲接口實例化對象並調用

java利用反射爲接口實例化對象並調用

package xxxxx;

import java.lang.reflect.Method;
import java.lang.reflect.Proxy;
import xxxxx.MyLibrary.MyCallback;

import java.lang.reflect.InvocationHandler;

class MyLibrary {
    public interface MyCallback {
        void doMyCallback();
    }
    public void mainMethod(MyCallback myCallback) {
        System.out.println("doing MyLibrary mainMethod...");
        myCallback.doMyCallback();
    }
}
class MyHandler implements InvocationHandler{
    @Override
    public Object invoke(Object proxy, Method method, Object[] args) throws Throwable {
        System.out.println("doing MyHandler invoke...");
        return null;
    }
}
public class Test3 {
    public static void main(String[] args) throws Exception {
    	Class<?> myLibraryClazz = Class.forName("xxxxx.MyLibrary");//類
        Class<?> myCallbackClazz = Class.forName("xxxxx.MyLibrary$MyCallback");//接口
        
        MyHandler myHandler = new MyHandler();//類
        MyCallback myCallback = (MyCallback)Proxy.newProxyInstance(
        		Test3.class.getClassLoader(),//類加載器
        		new Class[] { myCallbackClazz },//接口數組
        		myHandler//爲接口實現的對應具體方法
        	);//爲接口實例化對象
        Method method = myLibraryClazz.getDeclaredMethod("mainMethod", MyCallback.class);//（類名，參數類型）
        method.invoke(myLibraryClazz.newInstance(), myCallback);//調用方法，（實例化對象，內部接口實現對象）
    }
}

 運行結果：

doing MyLibrary mainMethod...
doing MyHandler invoke...