java.lang.IllegalArgumentException：主机名不能为null

大家好，我在这里发布我的问题，因为我已经阅读了所有帖子，但是没有得到任何帮助。我正在使用jersey网络服务，并尝试通过Android手机通过URL访问。我想从网络服务中打印问候消息，但它总是抛出异常java.lang.IllegalArgumentException Host name may not be null，已添加互联网许可，请检查我的活动

公共类MainActivity扩展了Activity {

@Override
protected void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.fragment_main);


    EditText content = (EditText)this.findViewById(R.id.editText1);


    // Creating HTTP client
    HttpClient httpClient = new DefaultHttpClient();


    // Creating HTTP Post
    HttpGet httpget = new HttpGet("http://localhost:10.0.2.2:8009/BookService/rest/bookresource/hello");

HttpResponse res;
        try {
            res = httpClient.execute(httpget);


            BufferedReader br = null;
            StringBuilder sb = new StringBuilder();

            String line;


    br = new BufferedReader(new InputStreamReader(res.getEntity().getContent()));
            while ((line = br.readLine()) != null) {
                    sb.append(line);

                }

                 content.setText(sb);

        } catch (ClientProtocolException e) {
            // TODO Auto-generated catch block
            e.printStackTrace();
        } catch (IOException e) {
            // TODO Auto-generated catch block
            e.printStackTrace();
        }

}

}

这是logcat的输出

05-10 01:38:24.768: D/AndroidRuntime(1438): Shutting down VM
05-10 01:38:24.768: W/dalvikvm(1438): threadid=1: thread exiting with uncaught exception (group=0xb4b0cba8)
05-10 01:38:24.818: E/AndroidRuntime(1438): FATAL EXCEPTION: main
05-10 01:38:24.818: E/AndroidRuntime(1438): Process: com.example.androidhttp, PID: 1438
05-10 01:38:24.818: E/AndroidRuntime(1438): java.lang.RuntimeException: Unable to start activity ComponentInfo{com.example.androidhttp/com.example.androidhttp.MainActivity}: **java.lang.IllegalArgumentException: Host name may not be null**

05-10 01:38:24.818: E/AndroidRuntime(1438):     at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2195)
05-10 01:38:24.818: E/AndroidRuntime(1438):     at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:2245)
05-10 01:38:24.818: E/AndroidRuntime(1438):     at android.app.ActivityThread.access$800(ActivityThread.java:135)
05-10 01:38:24.818: E/AndroidRuntime(1438):     at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1196)
05-10 01:38:24.818: E/AndroidRuntime(1438):     at android.os.Handler.dispatchMessage(Handler.java:102)
05-10 01:38:24.818: E/AndroidRuntime(1438):     at android.os.Looper.loop(Looper.java:136)
05-10 01:38:24.818: E/AndroidRuntime(1438):     at android.app.ActivityThread.main(ActivityThread.java:5017)
05-10 01:38:24.818: E/AndroidRuntime(1438):     at java.lang.reflect.Method.invokeNative(Native Method)
05-10 01:38:24.818: E/AndroidRuntime(1438):     at java.lang.reflect.Method.invoke(Method.java:515)
05-10 01:38:24.818: E/AndroidRuntime(1438):     at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:779)
05-10 01:38:24.818: E/AndroidRuntime(1438):     at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:595)
05-10 01:38:24.818: E/AndroidRuntime(1438):     at dalvik.system.NativeStart.main(Native Method)
05-10 01:38:24.818: E/AndroidRuntime(1438): Caused by: java.lang.IllegalArgumentException: Host name may not be null
05-10 01:38:24.818: E/AndroidRuntime(1438):     at org.apache.http.HttpHost.<init>(HttpHost.java:83)
05-10 01:38:24.818: E/AndroidRuntime(1438):     at org.apache.http.impl.client.AbstractHttpClient.determineTarget(AbstractHttpClient.java:497)
05-10 01:38:24.818: E/AndroidRuntime(1438):     at org.apache.http.impl.client.AbstractHttpClient.execute(AbstractHttpClient.java:487)
05-10 01:38:24.818: E/AndroidRuntime(1438):     at org.apache.http.impl.client.AbstractHttpClient.execute(AbstractHttpClient.java:465)
05-10 01:38:24.818: E/AndroidRuntime(1438):     at com.example.androidhttp.MainActivity.onCreate(MainActivity.java:59)
05-10 01:38:24.818: E/AndroidRuntime(1438):     at android.app.Activity.performCreate(Activity.java:5231)
05-10 01:38:24.818: E/AndroidRuntime(1438):     at android.app.Instrumentation.callActivityOnCreate(Instrumentation.java:1087)
05-10 01:38:24.818: E/AndroidRuntime(1438):     at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2159)
05-10 01:38:24.818: E/AndroidRuntime(1438):     ... 11 more