How can my Servlet receive parameters from a multipart/form-data form?

问题

I have a page that has this piece of code:

<form action="Servlet" enctype="multipart/form-data">
<input type="file" name="file">
<input type="text" name="text1">
<input type="text" name="text2">
</form>

When I use request.getParameter("text1"); in my Servlet it shows null. How can I make my Servlet receive the parameters?

回答1:

All the request parameters are embedded into the multipart data. You'll have to extract them using something like Commons File Upload: http://commons.apache.org/fileupload/

回答2:

Use getParts()

回答3:

Pleepleus is right, commons-fileupload is a good choice.
If you are working in servlet 3.0+ environment, you can also use its multipart support to easily finish the multipart-data parsing job. Simply add an @MultipartConfig on the servlet class, then you can receive the text data by calling request.getParameter(), very easy.

Tutorial - Uploading Files with Java Servlet Technology

回答4:

You need to send the parameter like this:

writer.append("--" + boundary).append(CRLF);
writer.append("Content-Disposition: form-data; name=\"" + urlParameterName + "\"" )
                .append(CRLF);
writer.append("Content-Type: text/plain; charset=" + charset).append(CRLF);
writer.append(CRLF);
writer.append(urlParameterValue).append(CRLF);
writer.flush();

And on servlet side, process the Form elements:

items = upload.parseRequest(request);
Iterator iter = items.iterator();
while (iter.hasNext()) {
       item = (FileItem) iter.next();
       if (item.isFormField()) {
          name = item.getFieldName(); 
          value = item.getString();

   }}

来源：https://stackoverflow.com/questions/9667169/how-can-my-servlet-receive-parameters-from-a-multipart-form-data-form

标签

java

servlets

parameters

multipart

form-data