JSP with multipart form

[Chuan Ren]

Can I find out why is it is I use multipart/form-data in the following, the JSP does not work?

Thank you.

 
<% if (request.getParameter("action") == null ) { %>
 
<FORM ENCTYPE="multipart/form-data" METHOD="post" ACTION="<%= request.getRequestURI() %>">
 
<INPUT class="buttons" TYPE="submit" NAME="action" VALUE="Submit">
 
</FORM>
 
<% } else if (request.getParameter("action").equals("Submit")) { 
 

 out.println("successful");
 
}%> 

[rimzim sinha]

what is the error u get?

[Chuan Ren]

There is no error message. the page just gone blank and did not go to the second condition. very weird.

[Dharmanand Singh]

There are many solutions. I have also listed the advantages of each.

Problem: javax.servlet.HttpServletRequest.getParameter(String) returns null when the ContentType is multipart/form-data

Solutions:

Solution A: (Advantage: Free Distribution & Widely used)

1. Download one of the versions of UploadFile from http://jakarta.apache.org/commons/fileupload/
2. Invoke parseRequest(request) on org.apache.commons.fileupload.FileUploadBase which returns list of org.apache.commons.fileupload.FileItem objects.
3. Invoke isFormField() on each of the FileItem objects. This determines whether the file item is a form paramater or stream of uploaded file.
4. Invoke getFieldName() to get parameter name and getString() to get parameter value on FileItem if it's a form parameter. Invoke write(java.io.File) on FileItem to save the uploaded file stream to a file if the FileItem is not a form parameter.

Solution B (Advantage: Easy to use)

1. Download http://www.servlets.com/cos/index.html
2. Invoke getParameters() on com.oreilly.servlet.MultipartRequest

Solution C (Restricted to those applications that use this framework):

Use Struts. Struts 1.1 handles this automatically.