Identify html form or its encoding (text or file) in servlet

Question

How do I recognize in a servlet whether the request sent using HTML form has enctype multipart/form-data or the default application/x-www-form-urlencoded?

Alternatively: is there any other way to recognize which form was used? request.getParameter("some_param") works only with default encoding.

Just use `request.getPart("some_param")` or Apache Commons FileUpload. See also [How to upload files in JSP/Servlet?](http://stackoverflow.com/questions/2422468/how-to-upload-files-in-jsp-servlet/2424824#2424824) Don't try to parse it yourself, for sure not if you're already asking trivial questions like this. — BalusC, May 31 '12 at 14:21
@BalusC It's better to ask than write something really wrong... I'm using Apache Commons FileUpload for multipart, but wasn't sure how to switch between handling multipart and default forms. — yosh, May 31 '12 at 14:31

Ramesh PVK · Answer 1 · 2012-05-31T15:32:35.207

1

You can identify using Content-Type: header

if(HttpServletRequest.getContentType().contains("form-data")){
   //handle multipart data
 ....
} else if(HttpServletRequest.getContentType().contains("x-www-form-urlencoded")){
   //handle from data
 ....
}

If the web container supports Servlet 3.0, the use HttpServletRequest.getParts() API.

if(request.getParts() !=null){
  //handle multipart
} else {
  //handle form data
}

edited May 31 '12 at 15:32

answered May 31 '12 at 09:52

Ramesh PVK

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1

Don't use `.contains()` when you should be using `.equals()` or `.equalsIgnoreCase()`. In this case it's probably not a problem, but it's still sloppy. – Christoffer Hammarström May 31 '12 at 12:38

score 1 · Accepted Answer · answered May 31 '12 at 14:34

1

I'm using Apache Commons FileUpload for multipart, but wasn't sure how to switch between handling multipart and default forms

Use Apache Commons FileUpload's own ServletFileUpload#isMultipartContent() to check it.

if (ServletFileUpload.isMultipartContent(request)) {
    // Parse with FileUpload.
}
else {
    // Use normal getParameter().
}

Identify html form or its encoding (text or file) in servlet

2 Answers2

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