Question

I have developed a Java EE web application. This application allows a user to upload a file with the help of a browser. Once the user has uploaded his file, this application first stores the uploaded file on the server (on which it is running) and then processes it.

At present, I am storing the file on the server as follows:

try {
    // formFile represents the uploaded file
    FormFile formFile = programForm.getTheFile();
    String path = getServlet().getServletContext().getRealPath("") + "/"
        + formFile.getFileName();
    System.out.println(path);
    file = new File(path);
    outputStream = new FileOutputStream(file);
    outputStream.write(formFile.getFileData());
}

where, the formFile represents the uploaded file.

Now, the problem is that it is running fine on some servers but on some servers the getServlet().getServletContext().getRealPath("") is returning null so the final path that I am getting is null/filename and the file doesn’t store on the server.

When I checked the API for ServletContext.getRealPath() method, I found the following:

public java.lang.String getRealPath(java.lang.String path)

Returns a String containing the real path for a given virtual path. For example, the path "/index.html" returns the absolute file path on the server’s filesystem would be served by a request for "http://host/contextPath/index.html", where contextPath is the context path of this ServletContext.

The real path returned will be in a form appropriate to the computer and operating system on which the servlet container is running, including the proper path separators. This method returns null if the servlet container cannot translate the virtual path to a real path for any reason (such as when the content is being made available from a .war archive).

So, Is there any other way by which I can store files on those servers also which is returning null for getServlet().getServletContext().getRealPath("")

Answer 1

Writing to the file system from a Java EE container is not really recommended, especially if you need to process the written data:

• it is not transactional
• it harms the portability (what if you are in a clustered environment)
• it requires to setup external parameters for the target location

If this is an option, I would store the files in database or use a JCR repository (like Jackrabbit).