JSP / Servlet upload images

[Kevin P Smith]

Hi guys

Just wondering if you could help with my next issue?

i am writing a function that allows the user to upload images/metadata from their localk machine onto my web syste,

this is done in 3 steps:
1. browse to and select images from local hard-disk, click upload > continue
2. goto next page and enter metadata > continue
3. goto next display summary of images and metadata > confirm

now I can do all this except I can't get the upload image thing working.

I think i need to use something like

JSP

<form name="Step1" enctype="multipart/form-data" action="/LoaderServlet" method="POST">
<input type="hidden" name="step" value="1" />
    <input type="file" name="filetoupload" />    <input type="submit" value="Upload" />
</form>

Servlet

    ServletInputStream in = request.getInputStream();

1. Why does the JSP return NULL for the hidden value 'step' when I put the [enctype="multipart/form-data"] in the <form>>

2. What do I have to do in the Servlet to 'get' the image data?

Any help greatly appreciated

KS

[Ben Souther]

There are already libraries out there that make it easy to do this.
See:
http://faq.javaranch.com/java/FileUpload

[Ben Souther]

1. Why does the JSP return NULL for the hidden value 'step' when I put the [enctype="multipart/form-data"] in the <form>>

Multipart forms work differently from regular form submissions.
Because of this, request.getProperty doesn't work with them.
The libraries mentioned in the link I gave you all have their own way of retrieving form parameters when uploading.

[Kevin P Smith]

Cheers guys

I'm using the Jakarta Fileupload JAR but have hit a snag!

The files I am uploading are images, which I need to then 'retrieve' on the next JSP page to display.

So far i have this code in the Servlet

boolean isMultipart = ServletFileUpload.isMultipartContent(request);
List<?> listOfFiles = null;
if (isMultipart) {
   // Create a factory for disk-based file items
   FileItemFactory factory = new DiskFileItemFactory();
 
   // Create a new file upload handler
   ServletFileUpload upload = new ServletFileUpload(factory);
 
   // Parse the request
   listOfFiles = upload.parseRequest(request);
}
 
Iterator<?> it = listOfFiles.iterator();
int i = 0;
while (it.hasNext()) {
    i++;
    FileItem item = (FileItem) it.next();
    byte[] data = item.get();
 

    /*
     * I need something in here to do something like :
     *        request.setAttribute("img"+i, new String(data));
    */
}

Then I need to display the image in a JSP file so was gonna do the usual:

   <%=request.getAttribute("img1")%>
   <%=request.getAttribute("img2")%>
   <%=request.getAttribute("img3")%>
.
.
.

But I'm getting nothing back.
[ March 13, 2008: Message edited by: Keith Seller ]