smartgwt spring servlet and uploading files

Question

I've seen this question here before, but none of the solutions work for me. I have a SmartGWT app with Spring MVC. This all works great, and I have working RESTful web-services.

I have a form to upload not only the file, but also some meta data as well. There is an associated DataSource with this form:

private final String DEFAULT_FILE_UPLOAD_SERVICE_PATH = "upload";
private final String TARGET = "uploadTarget";

 public FileUploadForm()
{
    setEncoding(Encoding.MULTIPART);
    setMethod(FormMethod.POST);

    setAutoFetchData(false);
    setDataSource(fileUploadDS);

    setTitleOrientation(TitleOrientation.TOP);
    setNumCols(1);
    setColWidths("*");

    uploadFileIdItem.setRequired(true);
    uploadFileIdItem.setDefaultValue(0);
    uploadFileIdItem.setVisible(false);
    uploadFileIdItem.setShowTitle(false);

    // ==========================================================================

    fileUploadTypeSelectItem.setShowTitle(false);
    fileUploadTypeSelectItem.setName(Constants.FILE_UPLOAD_UPLOADTYPE);
    fileUploadTypeSelectItem.setPickListWidth(TEXT_SIZE);
    fileUploadTypeSelectItem.setTitle(Constants.TITLE_FILE_UPLOAD_UPLOADTYPE);
    fileUploadTypeSelectItem.setOptionDataSource(fileUploadTypeDS);
    fileUploadTypeSelectItem.setRequired(true);
    fileUploadTypeSelectItem.setDisplayField(Constants.FILE_UPLOAD_UPLOADTYPE_NAME);
    fileUploadTypeSelectItem.setValueField(Constants.FILE_UPLOAD_UPLOADTYPE_ID);
    fileUploadTypeSelectItem.setDataPath("fileUploadType/fileUploadTypeId");

    // ==========================================================================

    setAction(GWT.getHostPageBaseURL() + "rest/" + DEFAULT_FILE_UPLOAD_SERVICE_PATH);

    ButtonItem uploadButton = new ButtonItem("Upload");

    uploadButton.addClickHandler(new com.smartgwt.client.widgets.form.fields.events.ClickHandler()
    {
        @Override
        public void onClick(com.smartgwt.client.widgets.form.fields.events.ClickEvent event)
        {
            submitForm();
        }
    });

    FileItem uploadItem = new FileItem(Constants.FILENAME);
    uploadItem.setTitle(Constants.FILENAME);

    setFields(uploadFileIdItem, fileUploadTypeSelectItem, uploadItem, uploadButton);
}

So, I don't know if I need to use: setAction(GWT.getHostPageBaseURL() + "rest/" + DEFAULT_FILE_UPLOAD_SERVICE_PATH); or setAction(GWT.getHostPageBaseURL() + DEFAULT_FILE_UPLOAD_SERVICE_PATH); or setAction(GWT.getHostPageBaseURL() + DEFAULT_FILE_UPLOAD_SERVICE_PATH);

None of these seem to work, I submit my data to upload the filename, and I constantly get the HTTP 404 error.

I did not define anything extra special in the web.xml file for servlets. Instead, the springmvc-servlet contains:

<context:component-scan base-package="com.myself.products.app.server.controller" />

And the servlet is actually defined like:

@SuppressWarnings("serial")
@Controller
@RequestMapping("/upload")
public class FileUploadServlet extends HttpServlet
{
    private final Logger logger = LoggerFactory.getLogger(FileUploadServlet.class);

    @Override
    public void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException
{
    this.process(request, response);
}

@Override
public void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException
{
    this.process(request, response);
}

private void process(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException
{
    // check that we have a file upload request
    if (ServletFileUpload.isMultipartContent(request))
    {
        processFiles(request, response);
    }
}

private File tmpDir;
private static final String DESTINATION_DIR_PATH = "/files/upload";
private File destinationDir;

public void init(ServletConfig config) throws ServletException
{
    super.init(config);

    tmpDir = new File(((File) getServletContext().getAttribute("javax.servlet.context.tempdir")).toString());

    if (!tmpDir.isDirectory())
    {
        throw new ServletException(tmpDir.toString() + " is not a directory");
    }

    logger.debug("tmpDir: " + tmpDir.toString());

    String realPath = getServletContext().getRealPath(DESTINATION_DIR_PATH);
    destinationDir = new File(realPath);

    if (!destinationDir.isDirectory())
    {
        throw new ServletException(DESTINATION_DIR_PATH + " is not a directory");
    }
}

private void processFiles(HttpServletRequest request, HttpServletResponse response) throws ServletException,
    IOException
{

    // create a factory for disk-based file items
    DiskFileItemFactory factory = new DiskFileItemFactory();

    // set the size threshold, above which content will be stored on disk
    factory.setSizeThreshold(1 * 1024 * 1024); // 1 MB

    // set the temporary directory (this is where files that exceed the threshold will be stored)
    factory.setRepository(tmpDir);

    // create a new file upload handler
    ServletFileUpload upload = new ServletFileUpload(factory);

    try
    {
        // parse the request
        List<?> items = upload.parseRequest(request);

        // process the uploaded items
        Iterator<?> itr = items.iterator();

        while (itr.hasNext())
        {
            FileItem item = (FileItem) itr.next();

            // write the uploaded file to the application's file staging area
            File file = new File(destinationDir, item.getName());
            item.write(file);
        }

    }
    catch (FileUploadException e)
    {
        logger.error("Error encountered while parsing the request", e);
    }
    catch (Exception e)
    {
        logger.error("Error encountered while uploading file", e);
    }
}

You've seen this code before along this web-site, and several others.

I'd like to submit the file, AND data if possible, but if not, then how can I submit the form, and then metadata for it?

Any help would be much appreciated.

Answer 1

Simple File Upload GWT Example:

Available here: http://www.gwtproject.org/javadoc/latest/com/google/gwt/user/client/ui/FileUpload.html

For sending Metadata along with request, need to set the hidden field to panel:

import com.google.gwt.user.client.ui.Hidden;

Hidden hidden = new Hidden();
hidden.setName("json");
hidden.setVisible(false); 

hidden.setValue("simpleMetadata:testData");
panel.add(hidden);