Day: July 18, 2013

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HTTP GET Using The Low Level Java App Engine API

Here’s a short code example showing how to do a HTTP GET using the low level Java API.

The variable url_string_here is the URL being retrieved as a String. It returns a byte[] array containing the content of the response. If the response code is not 200 (i.e. anything other than HTTP OK) then this code throws a RuntimeException.

URL url = new URL(url_string_here);
HTTPRequest request = new HTTPRequest(url, HTTPMethod.GET);
request.setHeader(new HTTPHeader("User-Agent", "Custom User Agent "));
//Execute request.
HTTPResponse response = URLFetchServiceFactory.getURLFetchService().fetch(request);
if (response.getResponseCode() == 200) {
    //The response was OK
    //Retrieve the content of the response.
    return response.getContent();
}//end if the response code was 200.
else {
    throw new RuntimeException("Response code was " + response.getResponseCode());
}