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Java - Creating files

Started by Mastermind25200 Apr 24, 2005 at 2:12 AM 1 reply 550+ views

Original Post

Apr 24, 2005 at 2:12 AM

I have a small problem. I was messing around in Java with the file IO for a game I'm going to make. Well, I want to be able to create a file if it doesn't exist, however if it DOES exist, then do absolutely nothing. It's probably real simple, but I don't know how to do this in Java. Any help? Thanks.

stormrunner

Apr 24, 2005 at 2:23 AM

Yeah, it's pretty simple. Just use the java.io.File class, and check to see if it exists e.g. :

import java.io.*;// ...// inside some function somewhere// ...File file = new File("myFile.txt");if(file.exists()){   System.out.println("The file [" + filename + "] exists");   // since it exists, just return, continue or break   return;}else // create the file using a FileOutputStream or something{   // here, we use a FileOutputStream,   // but you should use a BufferedOutputStream   // in most situations for performance reasons   // if you're going to keep the stream open and use it   try {      FileOutputStream filestream = new FileOutputStream(file);   // the file has been created   // close it ... or do something else   }   catch(IOException ex) {      // save the day   }}

You should (might) probably need to wrap that in a try/catch block, but that should do the trick. For directories you can do something like the following

File f = new File("omgDir");f.mkDir();

to create a directory, though be careful - java.io functions aren't known for their reliability.

<edit :: I just realized you could substitute the FileOutputStream code with a simple file.createNewFile() (it's late). I just assumed you would want to replace the data but that should be a little easier.

Spudder

Apr 24, 2005 at 6:47 AM

Your going to need a try/catch block for FileNotFoundException, the compiler won't let you get away without one since it's a checked exception.

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