Question

I am trying to retrieve a text file from the internet using the apache httpclient. I am using the following code:

        HttpClient httpclient = new DefaultHttpClient();
        HttpGet getHNMR = new HttpGet("http://www.hmdb.ca/labm/metabolites/" + HMDB + "/chemical/pred_hnmr_peaklist/" + HMDB + "_peaks.txt");
        HttpGet getCNMR = new HttpGet("http://www.hmdb.ca/labm/metabolites/" + HMDB + "/chemical/pred_cnmr_peaklist/" + HMDB + "_peaks.txt");

        try {
            responseH = httpclient.execute(getHNMR);
            responseC = httpclient.execute(getCNMR);
        } catch (ClientProtocolException e1) {
            // TODO Auto-generated catch block
            e1.printStackTrace();
            System.out.println("client exception");
        } catch (IOException e1) {
            // TODO Auto-generated catch block
            e1.printStackTrace();
            System.out.println("ioexception");
        }
        //Generate HNMR peak list
        HttpEntity entityH = responseH.getEntity();
        HttpEntity entityC = responseH.getEntity();;
        try {
            HNMR = EntityUtils.toString(entityH);
            CNMR = EntityUtils.toString(entityC);
        } catch (ParseException e1) {
            // TODO Auto-generated catch block
            e1.printStackTrace();
            System.out.println("parseexception");
        } catch (IOException e1) {
            // TODO Auto-generated catch block
            e1.printStackTrace();
            System.out.println("ioexception");
        }
    //Set peak lists to textarea
        HC.setText(CNMR + "\n" + HNMR);

I am getting the following stack trace:

Thread [pool-2-thread-1] (Suspended (exception IllegalStateException))  
ThreadPoolExecutor.runWorker(ThreadPoolExecutor$Worker) line: 1128  
ThreadPoolExecutor$Worker.run() line: 603   
Thread.run() line: 679  

I’m not that familiar with debugging, so I’m not sure what’s exactly happening.

Answer 1

The response body must be consumed before the connection can be used for another request. You should read the response InputStream fully prior to the next HTTP execute. Your code should be appear in the following order:

    responseH = httpclient.execute(getHNMR);
    HttpEntity entityH = responseH.getEntity();
    HNMR = EntityUtils.toString(entityH);

    responseC = httpclient.execute(getCNMR);
    HttpEntity entityC = responseC.getEntity();
    CNMR = EntityUtils.toString(entityC);