Content Type header for POST request

I have in Java (similar in other languages, problem should be language independent) a POST request I am sending to the server. The POST request contains only some POST parameters no body.

I basically have this:

postData = URLEncoder.encode("user", "UTF-8") + "=" + URLEncoder.encode("jackychan", "UTF-8");
//HttpSessionToken.setRequestProperty("Content-Type", "application/xml");
OutputStream postContent = (OutputStream)HttpSessionToken.getOutputStream();
postContent.write(postData.getBytes("UTF-8"));

This works fine. The question is around the second line, a comment at the moment. Uncommenting this line ruins my code, okay my data is not XML so I can understand this. 开发者_如何学JAVATo some REST services you have to POST a whole XML document, but no POST parameters, something like this

postData = "<xml> whatever xml structure here </xml>"  
HttpSessionToken.setRequestProperty("Content-Type", "application/xml");
OutputStream postContent = (OutputStream)HttpSessionToken.getOutputStream();
postContent.write(postData.getBytes("UTF-8"));

This works too. The difference is the postData is now an XML and the content type is set.

The question now is, what if a Service requires BOTH, POST parameters as in example 1 AND an xml body as in example 2. How would I do this? If that never happens, why doesn't it happen?

Thanks, A.

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You could do that as multipart/form-data so you can have mixed content in a single POST body. It's similar to multipart-mime, and each part can have its own content-type. Here's a previous stackoverflow answer for multipart form-data in Java: How can I make a multipart/form-data POST request using Java?