Writing to a Web Log (Text File) Java EE

Question

I'm having real trouble generating a text file per 'operation' to store operation specific information, no matter what approach I take, I can't create a text file on the web server, let alone store information within it, the first example is ideally what I'd like (create and store per operation)

Note - I'm trying to do this in a servlet currently for testing purposes. Help much appreciated.

 try {
               FileWriter fstream = new FileWriter("out.txt");
                BufferedWriter out = new BufferedWriter(fstream);
                out.write("test");
                out.close();
            } catch (Exception ex) {
                 System.out.println(ex);
            }

Different Approach

 try {

            URL                url; 
            URLConnection      urlConn; 
            DataOutputStream   dos;
            DataInputStream dis;

            url = new URL("http://localhost:8080/" + request.getContextPath() + "/tmp/myfile.txt");
            System.out.println(url);
            urlConn = url.openConnection(); 
            urlConn.setDoInput(true); 
            urlConn.setDoOutput(true); 
            urlConn.setUseCaches(false); 
            urlConn.setRequestProperty ("Content-Type", "text/plain");

            dos = new DataOutputStream (urlConn.getOutputStream()); 
            dos.writeUTF("test");
            dos.flush(); 
            dos.close();

            //to test
            dis = new DataInputStream(urlConn.getInputStream()); 
            String s = dis.readLine(); 
            System.out.println(s);
            dis.close(); 

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

Does your have permission to write the file to the filesystem? — jamesmortensen
– jamesmortensen, Commented Mar 12, 2012 at 21:50
I'm developing locally on Windows at the moment, I'll try CHMOD some folders now, thanks! — Ash
– Ash, Commented Mar 12, 2012 at 21:52

Dave Newton · Accepted Answer · 2012-03-12 22:33:28Z

1

Not sure why you'd want to do this like this; there's already robust logging solutions, and databases.

In the first case, it's almost certainly creating a file if you're not getting exceptions, you just don't know where it is. Use either an absolute path to a known-accessible location, or something relative to the application itself using .getRealPath.

(Noting that trying to write to an app-relative path won't work if you're deploying a war.)

In the second case, not sure why you thought that would work.

edited Mar 12, 2012 at 22:33

answered Mar 12, 2012 at 21:56

Dave Newton

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2 Comments

Ash Over a year ago

I've managed generate/locate the filepath using .getRealPath. I'm already using a database to log data, I just need to use a text file too. No doubt I'll encounter permission issues when on a server, but until then this will have to do, thanks!

Dave Newton Over a year ago

@Ash No problem; glad you got it working. Still seems a bit weird to me, though.

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