StringBuilder的NullPointerException

我想我的尝试,接球会处理好的。

java.lang.RuntimeException: An error occured while executing doInBackground()
at android.os.AsyncTask$3.done(AsyncTask.java:200)
at java.util.concurrent.FutureTask$Sync.innerSetException(FutureTask.java:273)
at java.util.concurrent.FutureTask.setException(FutureTask.java:124)
at java.util.concurrent.FutureTask$Sync.innerRun(FutureTask.java:307)
at java.util.concurrent.FutureTask.run(FutureTask.java:137)
at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1068)
at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:561)
at java.lang.Thread.run(Thread.java:1102)
Caused by: java.lang.NullPointerException
at java.io.Reader.<init>(Reader.java:65)
at java.io.InputStreamReader.<init>(InputStreamReader.java:65)
at com.test.test.FinderMain.grabPlaneRoute(FinderMain.java:759)
at com.test.test.FinderMain.access$7(FinderMain.java:729)
at com.test.test.FinderMain$GetRouteTask.doInBackground(FinderMain.java:684)
at com.test.test.FinderMain$GetRouteTask.doInBackground(FinderMain.java:1)
at android.os.AsyncTask$2.call(AsyncTask.java:185)
at java.util.concurrent.FutureTask$Sync.innerRun(FutureTask.java:305)

第759行在grabPlaneRoute中,是包含“StringBuilder total=new StringBuilder();”的行

有人能帮个忙吗,快把我逼疯了!:-)

private void grabPlaneRoute(String adshex) {


    List<GeoPoint> localList = new ArrayList<GeoPoint>();

    HttpURLConnection con = null;
    URL url;
    InputStream is=null;
    try {
        url = new URL("http://www.testurl.com&test=" + adshex);

        con = (HttpURLConnection) url.openConnection();
        con.setReadTimeout(20000 /* milliseconds */);
        con.setConnectTimeout(60000 /* milliseconds */);
        con.setRequestMethod("GET");
        con.setDoInput(true);

        // Start the query
        con.connect();
        is = con.getInputStream();
    }catch (IOException e) {
                    //handle the exception !
        e.printStackTrace();
        return;
    }

    //localList = decodePoly(convertStreamToString(is));
    //Log.i("HTTP DUMP", convertStreamToString(is));

    BufferedReader r = new BufferedReader(new InputStreamReader(is),8024);
    StringBuilder total = new StringBuilder();
    String line;
     try {
    while ((line = r.readLine()) != null) {
        String[] separated = line.split(",");

        GeoPoint p = getPoint(Double.valueOf(separated[0]),Double.valueOf(separated[1]));
        localList.add(p);
    }
     }catch (IOException e) {
         //handle the exception !
            e.printStackTrace(); 
     }



    drawPlaneRoute(localList);


}