Multiple files upload using REST

Question

I have a input type=file tag in my html which allows user to select multiple files. The action for the form is a REST web service:

@POST
@Path("savefile")
@Produces ({MediaType.TEXT_PLAIN})
public String createObjects(
        @FormDataParam("datafile") FormDataMultiPart file,
        @FormParam("username") String unm
        //@Context HttpServletRequest request
        ){....}

Initially I used the request object to retrieve all FileItems in the request and then saved it to the server. No problem with that. Now I want to send a string data along with the files. For that I read that the parameters need to be of type FormDataParam. Hence I have added that parameter. This is my client code :

<form id="form1" action="http://comp1:8080/RestWSGS/jersey/UploadFiles/savefile"
        enctype="multipart/form-data" method="post">
        <input name="username" type="text" style="display:none" value="abc"/>
  <input id="loadId" multiple="multiple" 
        type="file" name="datafile" required="required" autofocus="autofocus"
        onchange="selectFiles(this)"/>
  <div>
    <input style="display: none;" type="submit" value="Send">
  </div>
 </form>  

I am not sure what must be the type of the file parameter to allow multiple files in it???? Either the file parameter gives me multiple files OR do I have to revert back to the @Context injection?? If so how will I retrieve the string parameter?

Any help is welcome!

EDIT: I have modified my REST ws to the following:

@POST
@Path("savefile")
//@Consumes (MediaType.MULTIPART_FORM_DATA)
public void createObjects(
        //@FormDataParam("datafile") FormDataMultiPart file,
        //@FormParam("username") String unm
        @Context HttpServletRequest request
        )
{
    try
    {
        FileHandler f;
        f = new FileHandler(new File (getClass().getResource("/" +getClass().getName().substring(
                0, getClass().getName().indexOf("."))).getPath()).getParent().replaceAll("\\\\", "\\\\\\\\")  + "/mylog.log");
        logger.addHandler(f);

    }
    catch (SecurityException e1)
    {
        logger.info(e1.getMessage());

    }
    catch (IOException e1)
    {
        logger.info(e1.getMessage());
        //e1.printStackTrace();
    }


    ApplicationConstants.ROOTPATH = new File (getClass().getResource("/" +getClass().getName().substring(
            0, getClass().getName().indexOf("."))).getPath()).getParent().replaceAll("\\\\", "\\\\\\\\") ;
    ApplicationConstants.ROOTPATH = ApplicationConstants.ROOTPATH.substring
    (0, ApplicationConstants.ROOTPATH.indexOf("\\") + 2);
    String user = request.getParameter("username");
    logger.info("ApplicationConstants.ROOTPATH" + ApplicationConstants.ROOTPATH);


    try
    {
        for (Part part : request.getParts())
        {
                try
                {
                    logger.info("part = " + part.getName());
                    if (!part.getName().equalsIgnoreCase("username"))
                    {
                        String fileName = processFileName(part.getName());
                        part.write(new File(ApplicationConstants.ROOTPATH + user + "\\" + fileName).getPath());
                    }

                    else
                    {
                         user = request.getParameter("username");
                         logger.info("user = " + user);
                    }
                }
                catch (IOException e)
                {
                    logger.info(e.getMessage());

                }
        }
    }
    catch (IOException e)
    {

    }
    catch (ServletException e)
    {

    }
}

But I am always getting the value from request.getParameter("username") as null. I dont know what is going wrong!! Is it illegal to send other data as well in a multipart/form-data form?? I need some pointers here. Please suggest any improvements in this code.

Answer 1

The following is the solution that works for me. The request parts in case of a multipart/formdata request can be accessed using the input stream in the part. I wanted to send a string and some files to my REST web service.I found a ServletFileUpload/ FIleItem example posted at a couple of web sites but I could not retrieve the string( I think it gives an exception if all data is not of file type). Hence I modified my web service to the following and not I can do the processing of a string and some files:

    private static  Logger   logger = Logger.getLogger("UploadFiles");
@POST
@Path("savefile")
public void createObjects(@Context HttpServletRequest request)
{
    try
    {
        FileHandler f;
        f = new FileHandler(new File (getClass().getResource("/" +getClass().getName().substring(
                0, getClass().getName().indexOf("."))).getPath()).getParent().replaceAll("\\\\", "\\\\\\\\")  + "/mylog.log");
        logger.addHandler(f);

    }
    catch (SecurityException e1)
    {
        logger.info(e1.getMessage());

    }
    catch (IOException e1)
    {
        logger.info(e1.getMessage());
    }
    ApplicationConstants.ROOTPATH = new File (getClass().getResource("/" +getClass().getName().substring(
            0, getClass().getName().indexOf("."))).getPath()).getParent().replaceAll("\\\\", "\\\\\\\\") ;
    ApplicationConstants.ROOTPATH = ApplicationConstants.ROOTPATH.substring
    (0, ApplicationConstants.ROOTPATH.indexOf("\\") + 2);
    String user = request.getParameter("username");
    logger.info("ApplicationConstants.ROOTPATH" + ApplicationConstants.ROOTPATH);
    logger.info("username" + user);
    try
                {
        for (Part part : request.getParts())
        {

                    logger.info("part = " + part.getName());
                    if (!part.getName().equalsIgnoreCase("username"))
                    {
                        try {
                        BufferedInputStream in = new BufferedInputStream(part.getInputStream());
                        String filename = getFilename(part);
                        boolean success = (new File(ApplicationConstants.ROOTPATH + user + "\\")).mkdir();
                        if (success) {
                        System.out.println("Directory: " + ApplicationConstants.ROOTPATH + user .trim()+ "\\" + " created");
                        }  
                        else
                        {
                            System.out.println("not created");
                        }
                        FileOutputStream out = new FileOutputStream(ApplicationConstants.ROOTPATH + user  + "\\" + filename);

                        byte[] data = new byte[1000];
                        int bytesRead = 0;
                        int offset = 0;
                        while (offset < part.getSize())
                        {
                          bytesRead = in.read(data);
                          if (bytesRead == -1)
                          {
                              break;
                          }
                          offset += bytesRead;
                           out.write(data);
                        }

                        in.close();

                        if (offset != part.getSize())
                        {
                          throw new IOException("Only read " + offset + " bytes; Expected " + part.getSize() + " bytes");
                        }
                        out.flush();
                        out.close();
                        }
                        catch (Exception e) 
                        {
                            logger.info(e.getMessage());
                        }
                    }
                    else
                    {
                        BufferedReader reader = new BufferedReader(new InputStreamReader(part.getInputStream(), "UTF-8"));
                        StringBuilder value = new StringBuilder();
                        char[] buffer = new char[1024];
                        reader.read(buffer);
                        value.append(buffer);
                         user = value.toString().trim();
                         logger.info("user = " + value);
                    }

}
    }
    catch (IOException e)
    {
        // TODO Auto-generated catch block
        e.printStackTrace();
    }
    catch (ServletException e)
    {
        // TODO Auto-generated catch block
        e.printStackTrace();
    }
}

Hope this helps someone!!