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// Create a FormPanel and point it at a service.
final FormPanel form = new FormPanel();
 //The /myFormHandler is a servlet
form.setAction("/myFormHandler");
 
 // Because we're going to add a FileUpload widget, we'll need to set the
// form to use the POST method, and multipart MIME encoding.
//VERY IMPORTANT when using FileUpload
form.setEncoding(FormPanel.ENCODING_MULTIPART);
form.setMethod(FormPanel.METHOD_POST);
 
// Create a panel to hold all of the form widgets.
VerticalPanel panel = new VerticalPanel();
form.setWidget(panel);
 
// Create a TextBox, giving it a name so that it will be submitted.
final TextBox tb = new TextBox();
tb.setName("textBoxFormElement");
panel.add(tb);
 
// Create a ListBox, giving it a name and some values to be associated with
 // its options.
ListBox lb = new ListBox();
lb.setName("listBoxFormElement");
lb.addItem("foo", "fooValue");
lb.addItem("bar", "barValue");
lb.addItem("baz", "bazValue");
panel.add(lb);
 
// Create a FileUpload widget.
FileUpload upload = new FileUpload();
upload.setName("uploadFormElement");
panel.add(upload);
 
// Add a 'submit' button.
panel.add(new Button("Submit", new ClickHandler() {
 
      public void onClick(ClickEvent event) {
           form.submit();
      }
}));

// Add an event handler to the form.
form.addSubmitHandler(new FormPanel.SubmitHandler() {
 
      public void onSubmit(SubmitEvent event) {
           // This event is fired just before the form is submitted. We can take
           // this opportunity to perform validation.
           if (tb.getText().length() == 0) {
               Window.alert("The text box must not be empty");
               event.cancel();
           }
      }
});
form.addSubmitCompleteHandler(new FormPanel.SubmitCompleteHandler() {
 
   public void onSubmitComplete(SubmitCompleteEvent event) {
         // When the form submission is successfully completed, this event is
         // fired. Assuming the service returned a response of type text/html,
        // we can get the result text here (see the FormPanel documentation for
        // further explanation).
        Window.alert(event.getResults());
    }
});

response.setContentType("text/html;charset=UTF-8");
 
//verify that the request is multipart
boolean isMultipart = ServletFileUpload.isMultipartContent(request);
 
FileItemFactory factory = new DiskFileItemFactory();
 
ServletFileUpload upload = new ServletFileUpload(factory);
try {
     //get the items from the request object
     List items = upload.parseRequest(request);
 
     Iterator iter = items.iterator();
     while(iter.hasNext()){
           Object obj = iter.next();
           //make sure the object is not null
           if(obj == null){
                continue;
           }
 
            FileItem item = (FileItem)obj;
 
           //if item is a form field then get the value from the item
          if(item.isFormField()){
              String name = item.getName();
              if(name.compareTo("textBoxFormElement")==0){
                   //do something with the text box value
                   String value = item.getString();
              }else{
                   //do something with the list box value
                   String value = item.getString();
              }
          //if the item is not a form field, you know you have
         //an uploaded file, and therefore you need to process
         //it as such.
        }else if(!item.isFormField()){
 
                //Here we can do whatever we want with the uploaded file.
               String name = item.getName();
        }
  }
 
     response.getWriter().write("Success in processing multipart MIME form");
} catch (Exception ex) {
}