使用Volley时格式错误的URL异常

Question

在Android中使用Android-Volley时获取以下错误。同样的问题仍未解决here ......

08-27 14:46:18.779  26990-26990/com.rev.volleydemo D/VOLLEY﹕ http://api.androidhive.info/volley/person_object.json
08-27 14:46:18.879  26990-27004/com.rev.volleydemo E/Volley﹕ [619] NetworkDispatcher.run: Unhandled exception java.lang.RuntimeException: Bad URL null
    java.lang.RuntimeException: Bad URL null
            at com.android.volley.toolbox.BasicNetwork.performRequest(BasicNetwork.java:151)
            at com.android.volley.NetworkDispatcher.run(NetworkDispatcher.java:114)
     Caused by: java.net.MalformedURLException
            at java.net.URL.<init>(URL.java:154)
            at java.net.URL.<init>(URL.java:127)
            at com.android.volley.toolbox.HurlStack.performRequest(HurlStack.java:102)
            at com.android.volley.toolbox.BasicNetwork.performRequest(BasicNetwork.java:97)
            at com.android.volley.NetworkDispatcher.run(NetworkDispatcher.java:114)

public class AppController extends Application {

    public static final String TAG = AppController.class
            .getSimpleName();

    private RequestQueue mRequestQueue;
    private ImageLoader mImageLoader;

    private static AppController mInstance;

    @Override
    public void onCreate() {
        super.onCreate();
        mInstance = this;
    }

    public static synchronized AppController getInstance() {
        return mInstance;
    }

    public RequestQueue getRequestQueue() {
        if (mRequestQueue == null) {
            mRequestQueue = Volley.newRequestQueue(getApplicationContext());
        }

        return mRequestQueue;
    }

    public ImageLoader getImageLoader() {
        getRequestQueue();
        if (mImageLoader == null) {
            mImageLoader = new ImageLoader(this.mRequestQueue,
                    new BitmapCache());
        }
        return this.mImageLoader;
    }

    public <T> void addToRequestQueue(Request<T> req, String tag) {
        // set the default tag if tag is empty
        req.setTag(TextUtils.isEmpty(tag) ? TAG : tag);
        getRequestQueue().add(req);
    }

    public <T> void addToRequestQueue(Request<T> req) {
        req.setTag(TAG);
        getRequestQueue().add(req);
    }

    public void cancelPendingRequests(Object tag) {
        if (mRequestQueue != null) {
            mRequestQueue.cancelAll(tag);
        }
    }
}

public class MainActivity extends AppCompatActivity {

    public final String URL = new String("http://api.androidhive.info/volley/person_object.json");

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);
        Log.d("VOLLEY", URL);

        JsonObjectRequest jsonObjectRequest = new JsonObjectRequest(Method.POST, null, URL, new Response.Listener<JSONObject>() {
            @Override
            public void onResponse(JSONObject response) {
                Log.d("VOLLEY", response.toString());
            }
        }, new Response.ErrorListener() {
            @Override
            public void onErrorResponse(VolleyError error) {
                Log.d("VOLLEY", error.toString());
            }
        });

        AppController.getInstance().addToRequestQueue(jsonObjectRequest, "JSON_OBJ");
    }
}