Android上的服务启动android.os.NetworkOnMainThreadException

我猜是与清单文件和权限相关的东西,服务在最后一个活动之后启动,更新服务器上的数据并检索新数据并在android上的sqlite上保存id：

这里还有清单文件：

<manifest xmlns:android="http://schemas.android.com/apk/res/android"
        package="com.ggservice.democracy"
        android:versionCode="1"
        android:versionName="1.0" >

        <uses-sdk
            android:minSdkVersion="8"
            android:targetSdkVersion="17" />
        <uses-permission android:name="android.permission.INTERNET"/>

        <application
            android:allowBackup="true"
            android:icon="@drawable/ic_launcher"
            android:label="@string/app_name"
            android:theme="@style/AppTheme" >
            <activity
                android:name="com.ggservice.democracy.MainActivity"
                android:label="@string/app_name" >
                <intent-filter>
                    <action android:name="android.intent.action.MAIN" />

                    <category android:name="android.intent.category.LAUNCHER" />
                </intent-filter>
            </activity>
            <activity android:label="@string/app_name" android:name="com.ggservice.democracy.sondaggioActivity"/>
            <activity android:label="@string/app_name" android:name="com.ggservice.democracy.domandeDiCategoria"/>
            <service android:name="com.ggservice.democracy.updateDemocracyService" />
        </application>

    </manifest>

logcat：

01-02 15:33:30.960: W/dalvikvm(2570): threadid=1: thread exiting with uncaught exception (group=0x409c01f8)
01-02 15:33:31.160: E/AndroidRuntime(2570): FATAL EXCEPTION: main
01-02 15:33:31.160: E/AndroidRuntime(2570): java.lang.RuntimeException: Unable to start service com.ggservice.democracy.updateDemocracyService@412f0c60 with Intent { cmp=com.ggservice.democracy/.updateDemocracyService }: android.os.networkonmainthreadException
01-02 15:33:31.160: E/AndroidRuntime(2570):     at android.app.ActivityThread.handleServiceArgs(ActivityThread.java:2376)
01-02 15:33:31.160: E/AndroidRuntime(2570):     at android.app.ActivityThread.access$1900(ActivityThread.java:123)
01-02 15:33:31.160: E/AndroidRuntime(2570):     at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1210)
01-02 15:33:31.160: E/AndroidRuntime(2570):     at android.os.Handler.dispatchMessage(Handler.java:99)
01-02 15:33:31.160: E/AndroidRuntime(2570):     at android.os.Looper.loop(Looper.java:137)
01-02 15:33:31.160: E/AndroidRuntime(2570):     at android.app.ActivityThread.main(ActivityThread.java:4424)
01-02 15:33:31.160: E/AndroidRuntime(2570):     at java.lang.reflect.Method.invokeNative(Native Method)
01-02 15:33:31.160: E/AndroidRuntime(2570):     at java.lang.reflect.Method.invoke(Method.java:511)
01-02 15:33:31.160: E/AndroidRuntime(2570):     at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:784)
01-02 15:33:31.160: E/AndroidRuntime(2570):     at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:551)
01-02 15:33:31.160: E/AndroidRuntime(2570):     at dalvik.system.NativeStart.main(Native Method)
01-02 15:33:31.160: E/AndroidRuntime(2570): Caused by: android.os.networkonmainthreadException
01-02 15:33:31.160: E/AndroidRuntime(2570):     at android.os.StrictMode$AndroidBlockGuardPolicy.onNetwork(StrictMode.java:1099)
01-02 15:33:31.160: E/AndroidRuntime(2570):     at java.net.InetAddress.lookupHostByName(InetAddress.java:391)
01-02 15:33:31.160: E/AndroidRuntime(2570):     at java.net.InetAddress.getAllByNameImpl(InetAddress.java:242)
01-02 15:33:31.160: E/AndroidRuntime(2570):     at java.net.InetAddress.getAllByName(InetAddress.java:220)
01-02 15:33:31.160: E/AndroidRuntime(2570):     at org.apache.http.impl.conn.DefaultClientConnectionoperator.openConnection(DefaultClientConnectionoperator.java:137)
01-02 15:33:31.160: E/AndroidRuntime(2570):     at org.apache.http.impl.conn.AbstractPoolEntry.open(AbstractPoolEntry.java:164)
01-02 15:33:31.160: E/AndroidRuntime(2570):     at org.apache.http.impl.conn.AbstractPooledConnAdapter.open(AbstractPooledConnAdapter.java:119)
01-02 15:33:31.160: E/AndroidRuntime(2570):     at org.apache.http.impl.client.DefaultRequestDirector.execute(DefaultRequestDirector.java:360)
01-02 15:33:31.160: E/AndroidRuntime(2570):     at org.apache.http.impl.client.AbstractHttpClient.execute(AbstractHttpClient.java:555)
01-02 15:33:31.160: E/AndroidRuntime(2570):     at org.apache.http.impl.client.AbstractHttpClient.execute(AbstractHttpClient.java:487)
01-02 15:33:31.160: E/AndroidRuntime(2570):     at org.apache.http.impl.client.AbstractHttpClient.execute(AbstractHttpClient.java:465)
01-02 15:33:31.160: E/AndroidRuntime(2570):     at com.ggservice.democracy.JSONParser.getJSONFromUrl(JSONParser.java:38)
01-02 15:33:31.160: E/AndroidRuntime(2570):     at com.ggservice.democracy.updateDemocracyService.onStartCommand(updateDemocracyService.java:47)
01-02 15:33:31.160: E/AndroidRuntime(2570):     at android.app.ActivityThread.handleServiceArgs(ActivityThread.java:2359)
01-02 15:33:31.160: E/AndroidRuntime(2570):     ... 10 more

难道我做错了什么？

这也是服务：

public class updateDemocracyService extends Service{
    private pollDataSource datasource;
     int mStartMode;       // indicates how to behave if the service is killed
        IBinder mBinder;      // interface for clients that bind
        boolean mAllowRebind; // indicates whether onRebind should be used
        // url to make request
        private static String url = "http://www.test.com/democracy/domande.PHP";

        // JSON Node names
        private static final String TAG_DOMANDE = "domande";
        private static final String TAG_ID = "id";
        private static final String TAG_TESTO = "testo";


        // contacts JSONArray
        JSONArray contacts = null;

        @Override
        public void onCreate() {
            // The service is being created
            datasource = new pollDataSource(this);
            datasource.open();

        }
        @Override
        public int onStartCommand(Intent intent,int flags,int startId) {

            // Creating JSON Parser instance
            JSONParser jParser = new JSONParser();

            // getting JSON string from URL
            JSONObject json = jParser.getJSONFromUrl(url);

            try {
                // Getting Array of Contacts
                contacts = json.getJSONArray(TAG_DOMANDE);

                // looping through All Contacts
                for(int i = 0; i < contacts.length(); i++){
                    JSONObject c = contacts.getJSONObject(i);

                    // Storing each json item in variable
                    String id = c.getString(TAG_ID);
                    String name = c.getString(TAG_TESTO);
                    datasource.createCategoria(name);
                }
            } catch (JSONException e) {
                e.printstacktrace();
            }




            Toast.makeText(this,"ho comunicato con un server!",Toast.LENGTH_LONG).show();  
            return mStartMode;
        }
        @Override
        public IBinder onBind(Intent intent) {
            // A client is binding to the service with bindService()
            return mBinder;
        }
        @Override
        public boolean onUnbind(Intent intent) {
            // All clients have unbound with unbindService()
            return mAllowRebind;
        }
        @Override
        public void onRebind(Intent intent) {
            // A client is binding to the service with bindService(),// after onUnbind() has already been called
        }
        @Override
        public void onDestroy() {
            datasource.close();
            // The service is no longer used and is being destroyed
        }


}