Question

These are days that I’m banging my head on this problem and maybe you that certainly know more than me you can help me ….
Then I try to explain better.

I have a javascript file that through the library d3.js builds the html code pages and replaces it with the other code each part a different function … The page will not charge (Ajax).
At some point I need to allow the user to upload an image to their profile picture so I make sure that the html code bait

<input type="file" id="file">

and a

<input type = "button" onclick = "javaScript: performAjaxSubmit ()">

PerformAjaxSubmit function () sends the data to a Java Servlet via a xmlHttpRequest level 2, which, from what I understand, can send not only strings but also more complex things such as files.

The function is as follows:

function performAjaxSubmit() {
    var sampleFile = document.getElementById("file").files[0];
    var formdata = new FormData();
    formdata.append("sampleFile", sampleFile);
    var xhr = new XMLHttpRequest();
    xhr.open("POST", "http://127.0.0.1:8080/Prova/Upload", true);
    xhr.send(formdata);
    xhr.onload = function(e) {
        if (this.status == 200) {
            alert(this.responseText);
        }
    };
}

The code in the Servlet instead is this:

protected void doPost(HttpServletRequest request,
        HttpServletResponse response) throws ServletException, IOException {
    // Check that we have a file upload request
    System.out.println(request.getAttribute("username"));
      isMultipart = ServletFileUpload.isMultipartContent(request);
      response.setContentType("text/html");
      java.io.PrintWriter out = response.getWriter( );

      DiskFileItemFactory factory = new DiskFileItemFactory();
      // maximum size that will be stored in memory
      factory.setSizeThreshold(maxMemSize);
      // Location to save data that is larger than maxMemSize.
      factory.setRepository(new File("C:/Users/Marty/workspaceJEE/Prova/WebContent/imm/utenti"));
      filePath="C:/Users/Marty/workspaceJEE/Prova/WebContent/imm/utenti";
      // Create a new file upload handler
      ServletFileUpload upload = new ServletFileUpload(factory);
      // maximum file size to be uploaded.
      upload.setSizeMax( maxFileSize );

      try{ 
      // Parse the request to get file items.
      List fileItems = upload.parseRequest(request);

      // Process the uploaded file items
      Iterator i = fileItems.iterator();

      while ( i.hasNext () ) 
      {
         FileItem fi = (FileItem)i.next();
         if ( !fi.isFormField () )  
         {
            // Get the uploaded file parameters
            String fieldName = fi.getFieldName();
            String fileName = fi.getName();
            String contentType = fi.getContentType();
            boolean isInMemory = fi.isInMemory();
            long sizeInBytes = fi.getSize();
            // Write the file
            if( fileName.lastIndexOf("\\") >= 0 ){
               file = new File( filePath +"/"+ 
               fileName.substring( fileName.lastIndexOf("\\"))) ;
            }else{
                System.out.println(filePath + 
               fileName.substring(fileName.lastIndexOf("\\")+1));
               file = new File( filePath +"/"+  
               fileName.substring(fileName.lastIndexOf("\\")+1)) ;
            }
            fi.write( file ) ;
         }
      }

   }catch(Exception ex) {
       System.out.println(ex);
   }
}

Now (sorry if the question is a bit long) it works but the problem is that the images are saved in the path that I have provided me with the command:

factory.setRepository(new File("C:/Users/Marty/workspaceJEE/Prova/WebContent/imm/utenti"));

How do I then save it remotely? That is, once I load the site of such Altrevista, how do I make sure that they are not pià saved to C but in a folder in your project?

I hope I explained. I’m using Apache Tomcat v7.0.
Thanks in advance!

Answer 1

You can use ServletContext.getRealPath

This code returns <context root>/upload (depends on your deployment configuration)

request.getSession().getServletContext().getRealPath("/upload")