fileUpload.java

/*
    File Upload
    on Spring project
*/

/*
    <form> in jsp need enctype attribute. For example:
    <form name="formA" id="formA" method="post" enctype="multipart/form-data" action="[your_address]">
    ...
    </form>
*/

if (ServletFileUpload.isMultipartContent(request)) {

    ServletFileUpload uploadHandler = new ServletFileUpload(new DiskFileItemFactory());

    // UTF-8 Encoding
    uploadHandler.setHeaderEncoding("UTF-8");
    List<FileItem> items = uploadHandler.parseRequest(request);

    // For each files
    for (FileItem item : items) {
        // If there's file
        if (item.getSize() > 0) {
            
            // Get default file path
            String defaultPath = request.getSession().getServletContext().getRealPath("/");
            // Get detail file path
            String path = defaultPath + "/upload/category1/";
            
            // On local server, path might be:
            // C:\workspace\[your_workspace_name]\.metadata\.plugins\org.eclipse.wst.server.core\tmp0\wtpwebapps\[your_project_name]\/upload/category1/

            // If no directory, make it
            File folder = new File(path);
            if (!folder.exists()) {
                folder.mkdirs();
            }
            
            // Get extension name
            String ext = item.getName().substring(item.getName().lastIndexOf(".") + 1);
            // Make a new filename for upload using UUID
            String realname = UUID.randomUUID().toString() + "." + ext;

            ///////////////// Write a file on server /////////////////
            InputStream is = item.getInputStream();
            OutputStream os = new FileOutputStream(path + realname);
            int numRead;
            byte b[] = new byte[(int) item.getSize()];
            while ((numRead = is.read(b, 0, b.length)) != -1) {
                os.write(b, 0, numRead);
            }
            if (is != null) is.close();
            os.flush();
            os.close();
            ///////////////// End /////////////////
        } else {
            // No files to upload
        }
    }
}