Apache Http EntityUtils.consume() 与 EntityUtils.toString()？

Question

I have written a HTTP client, where I am reading the data response from a REST web service. My confusion arises after reading multiple blogs on EntityUtils.consume() and EntiryUtils.toString(). I wanted to know the following:

1. If EntityUtils.toString(..) ONLY is sufficient as it also closes the stream after reading char bytes. Or I should also do EntityUtils.consume(..) as a good practice.

2. If both toString() and consume() operation can be used. If yes, then what should be there order.

3. If I EntityUtils.toString() closes the stream; then why the next call in EntityUtils.consume(..) operations which is entity.isStreaming() still returns true?

Could anyone guide me here to use these operations in a standard way. I am using HTTP version 4+.

I have to use these configurations in multithreaded(web-app) environment.

Thanks

Answer 1

I looked at the recommended example from the apache httpclient commons website.

In the example, they used EntityUtils.toString(..) without needing to use EntityUtils.consume(..) before or after.

They mention that calling httpclient.close() ensures all resources are closed.

source: https://hc.apache.org/httpcomponents-client-ga/httpclient/examples/org/apache/http/examples/client/ClientWithResponseHandler.java

CloseableHttpClient httpclient = HttpClients.createDefault();
    try {
        HttpGet httpget = new HttpGet("http://httpbin.org/");

        System.out.println("Executing request " + httpget.getRequestLine());

        // Create a custom response handler
        ResponseHandler<String> responseHandler = new ResponseHandler<String>() {

            @Override
            public String handleResponse(
                    final HttpResponse response) throws ClientProtocolException, IOException {
                int status = response.getStatusLine().getStatusCode();
                if (status >= 200 && status < 300) {
                    HttpEntity entity = response.getEntity();
                    return entity != null ? EntityUtils.toString(entity) : null;
                } else {
                    throw new ClientProtocolException("Unexpected response status: " + status);
                }
            }

        };
        String responseBody = httpclient.execute(httpget, responseHandler);
        System.out.println("----------------------------------------");
        System.out.println(responseBody);
    } finally {
        httpclient.close();
    }

This is what is quoted for the above example:

This example demonstrates how to process HTTP responses using a response handler. This is the recommended way of executing HTTP requests and processing HTTP responses. This approach enables the caller to concentrate on the process of digesting HTTP responses and to delegate the task of system resource deallocation to HttpClient. The use of an HTTP response handler guarantees that the underlying HTTP connection will be released back to the connection manager automatically in all cases.