jackson - java.io.IOException: Attempted read from closed stream

Question

I am making a HTTPPost call using Apache HTTP Client and then I am trying to create an object from the response using Jackson. Here is my code:

private static final Logger log = Logger.getLogger(ReportingAPICall.class);
ObjectMapper mapper = new ObjectMapper();

public void makePublisherApiCall(String jsonRequest)
{
    String url = ReaderUtility.readPropertyFile().getProperty("hosturl");
    DefaultHttpClient client = new DefaultHttpClient();
    try {
        HttpPost postRequest = new HttpPost(url);
        StringEntity entity = new StringEntity(jsonRequest);
        postRequest.addHeader("content-type", "application/json");
        log.info("pub id :"+ExcelReader.publisherId);
        postRequest.addHeader("accountId", ExcelReader.publisherId);
        postRequest.setEntity(entity);
        HttpResponse postResponse = client.execute(postRequest);
        log.info(EntityUtils.toString(postResponse.getEntity()));

    //  Response<PublisherReportResponse> response = mapper.readValue(postResponse.getEntity().getContent(), Response.class);
    //  log.info("Reponse "+response.toString());
    } catch (UnsupportedEncodingException ex) {
        log.error(ex.getMessage());
        log.error(ex);
        Assert.assertTrue(false, "Exception : UnsupportedEncodingException");
    } catch (ClientProtocolException ex) {
        log.error(ex.getMessage());
        log.error(ex);
        Assert.assertTrue(false, "Exception : ClientProtocolException");
    } catch (IOException ex) {
        log.error(ex.getMessage());
        log.error(ex);
        Assert.assertTrue(false, "Exception : IOException");
    }

Method makePublisherApiCall() will be called in a loop which runs for say 100 times. Basically problem occurs when I uncomment the line:

//  Response<PublisherReportResponse> response = mapper.readValue(postResponse.getEntity().getContent(), Response.class);
//  log.info("Reponse "+response.toString());

After uncommenting I am getting exception:

Attempted read from closed stream.
17:26:59,384 ERROR com.inmobi.reporting.automation.reportingmanager.ReportingAPICall - java.io.IOException: Attempted read from closed stream.

Otherwise it works fine. Could someone please let me know what I am doing wrong.

Answer 1

What does EntityUtils.toString(postResponse.getEntity()) do with the response entity? I would suspect, that it is consuming the entity's content stream. The HttpClient javadoc states, that only entities, which are repeatable can be consumed more than once. Therefore if the entity is not repeatable you cannot feed the content stream to the mapper again. To avoid this you should only let the mapper consume the stream - if logging of content is required, log the parsed Response object.