Upgrading POST request from HttpClient to HttpComponents. What's going wrong here? - legacy-code

Question

I inherited some old code that uses the now-deprecated Apache Commons HttpClient. I was tasked with upgrading it to use the newer Apache HttpComponents. However, I can't seem to get this POST request to function properly. The server keeps complaining that Content-Length = 0. I'm fairly certain that it's a problem with my conversion of how parameters are added.
The old HttpClient code looks something like this:
PostMethod postMethod = null;
int responseCode = 0;
try{
HttpClient httpClient = new HttpClient();
postMethod = new PostMethod(getServiceUrl()); //The url, without a query.
...
postMethod.addParameter(paramName, request);
responseCode = httpClient.executeMethod(postMethod);
...
}
And here are my HttpComponents replacements:
HttpPost postMethod = null;
int responseCode = 0;
HttpResponse httpResponse = null;
try{
HttpClient httpClient = new DefaultHttpClient();
postMethod = new HttpPost(getServiceUrl()); //The url, without a query.
...
BasicHttpParams params = new BasicHttpParams();
params.setParameter(paramName, request);
postMethod.setParams(params);
httpResponse = httpClient.execute(postMethod);
responseCode = httpResponse.getStatusLine().getStatusCode();
...
}
The servlet my code it talking to is using Apache Commons FileUpload. Here is the code it catches on when it receives my request:
ServletRequestContext src = new ServletRequestContext(request);
if (src.getContentLength() == 0)
throw new IOException("Could not construct ServletRequestContext object");
It used to pass this test just fine. Now it doesn't. I've tried all kinds of alternatives, such as using the header, or passing request as a URLEncoded query. Have I made a mistake in my upgrade, somewhere?
Note: I can't just change how the servlet receives my request, because then I'll have to change a number of other apps that talk to it, and that's too big a job.

Answer 1

To set the request body, you can use HttpPost's setEntity() method. You can explore the available entity types here. This would replace the BasicHttpParams code.
To send a form entity, for example:
HttpClient httpClient = new DefaultHttpClient();
HttpPost httpPost = new HttpPost("http://someurl");
List<NameValuePair> formParams = new ArrayList<NameValuePair>();
formParams.add(new BasicNameValuePair("name", "value"));
UrlEncodedFormEntity formEntity = new UrlEncodedFormEntity(formParams, "UTF-8");
httpPost.setEntity(formEntity);
HttpResponse httpResponse = client.execute(httpPost);