Ich bin relativ neu in der Android-Entwicklung. Ich entwickle eine Android-Anwendung, bei der ich eine Anfrage an den Webserver sende und JSON-Objekte analysiere. Häufig bekomme ichjava.net.SocketTimeoutException: Connection timed out Ausnahme bei der Kommunikation mit dem Server. Manchmal funktioniert es problemlos. Ich weiß, dass die gleiche Frage schon so oft gestellt wurde. Trotzdem habe ich keine zufriedenstellende Lösung für dieses Problem gefunden. Ich poste unten meinen Logcat- und App-Server-Kommunikationscode.

public JSONObject RequestWithHttpUrlConn(String _url, String param){

    HttpURLConnection con = null;
    URL url;
    String response = "";
    Scanner inStream = null;
    PrintWriter out = null;
    try {
        url = new URL(_url);
        con = (HttpURLConnection) url.openConnection();
        con.setDoOutput(true);
        con.setRequestMethod("POST");
        if(param != null){
            con.setFixedLengthStreamingMode(param.getBytes().length);
        }
        con.setRequestProperty("Content-Type", "application/x-www-form-urlencoded");
        out = new PrintWriter(con.getOutputStream());
        if(param != null){
            out.print(param);
        }
        out.flush();
        out.close();
        inStream = new Scanner(con.getInputStream());

        while(inStream.hasNextLine()){
            response+=(inStream.nextLine());
        }
    } catch (MalformedURLException e) {
        // TODO Auto-generated catch block
        e.printStackTrace();
    } catch (IOException e) {
        // TODO Auto-generated catch block
        e.printStackTrace();
    } finally{
        if(con != null){
            con.disconnect();
        }if(inStream != null){
            inStream.close();
        }if(out != null){
            out.flush();
            out.close();
        }
    }
}

Logcat:

03-25 10:55:32.613: W/System.err(18868): java.net.SocketTimeoutException: Connection 
timed out
03-25 10:55:32.617: W/System.err(18868):at org.apache.harmony.luni.platform.OSNetworkSystem.connect(Native Method)
03-25 10:55:32.617: W/System.err(18868):at dalvik.system.BlockGuard
$WrappedNetworkSystem.connect(BlockGuard.java:357)
03-25 10:55:32.617: W/System.err(18868):at 
org.apache.harmony.luni.net.PlainSocketImpl.connect(PlainSocketImpl.java:204)
03-25 10:55:32.617: W/System.err(18868):at 
org.apache.harmony.luni.net.PlainSocketImpl.connect(PlainSocketImpl.java:437)
03-25 10:55:32.617: W/System.err(18868):at        java.net.Socket.connect(Socket.java:1002)
03-25 10:55:32.621: W/System.err(18868):at 
org.apache.harmony.luni.internal.net.www.protocol.http.HttpConnection.<init>
(HttpConnection.java:75)
03-25 10:55:32.621: W/System.err(18868): at 
org.apache.harmony.luni.internal.net.www.protocol.http.HttpConnection.<init>
(HttpConnection.java:48)03-25 10:55:32.624: W/System.err(18868):at 
org.apache.harmony.luni.internal.net.www.protocol.http.HttpConnection$Address.connect
(HttpConnection.java:322)03-25 10:55:32.624: W/System.err(18868):at 
org.apache.harmony.luni.internal.net.www.protocol.http.HttpConnectionPool.get
(HttpConnectionPool.java:89)03-25 10:55:32.628: W/System.err(18868):at 
org.apache.harmony.luni.internal.net.www.protocol.http.HttpURLConnectionImpl.getHttpCon
nection(HttpURLConnectionImpl.java:285)
03-25 10:55:32.628: W/System.err(18868):at     org.apache.harmony.luni.internal.net.www.protocol.http.HttpURLConnectionImpl.makeConn
ection(HttpURLConnectionImpl.java:267)
03-25 10:55:32.636: W/System.err(18868):at
org.apache.harmony.luni.internal.net.www.protocol.http.HttpURLConnectionImpl.connect
(HttpURLConnectionImpl.java:205)
03-25 10:55:32.636: W/System.err(18868):at 
org.apache.harmony.luni.internal.net.www.protocol.http.HttpURLConnectionImpl.getOutputS
tream(HttpURLConnectionImpl.java:614)
03-25 10:55:32.636: W/System.err(18868):at 
com.myapp.core.JSONRequest.RequestWithHttpUrlConn(JSONRequest.java:63)
03-25 10:55:32.636: W/System.err(18868):    at com.myapp.core.DetailPage
$AsyncRecBooks.doInBackground(AKBookDetailView.java:265)
03-25 10:55:32.640: W/System.err(18868):    at com.myapp.core.DetailPage
$AsyncRecBooks.doInBackground(AKBookDetailView.java:1)
03-25 10:55:32.640: W/System.err(18868):    at android.os.AsyncTask$2.call
(AsyncTask.java:185)
03-25 10:55:32.640: W/System.err(18868):    at java.util.concurrent.FutureTask
$Sync.innerRun(FutureTask.java:306)
03-25 10:55:32.640: W/System.err(18868):    at java.util.concurrent.FutureTask.run
(FutureTask.java:138)
03-25 10:55:32.640: W/System.err(18868):    at 
java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1088)
03-25 10:55:32.648: W/System.err(18868):    at 
java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:581)
03-25 10:55:32.648: W/System.err(18868):    at java.lang.Thread.run(Thread.java:1019)
03-25 10:55:32.652: E/JSON Parser(18868): Error parsing data org.json.JSONException:  
End of input at character 0 of 

Kann mir jemand helfen, eine Lösung dafür zu finden? Danke im Voraus....