CODEWITHSUNDEEP
javafileoutputstreamfile-writing
Gilian Joosen
Gilian Joosen

Reputation: 486

Copying a file from a location to another location

I am trying to read a file and write it to a specific folder. I am using this code:

private void saveFile(File file){
    try {
        OutputStream out = new FileOutputStream(new File("/Users/default/Desktop/fotos/test.png"));
        Files.copy(file.toPath(), out);
                System.exit(0);

    } catch (IOException ex) {
        Logger.getLogger(GetFiles.class.getName()).log(Level.SEVERE, null, ex);
    }
}

The file is a .png file. If I use this method it will create a new .png in the fotos directory, but when I double click it it says that it's empty. How is this possible and how can I solve this?

Upvotes: 0

Views: 49

Answers (1)

Jon Skeet
Jon Skeet

Reputation: 1500645

You're not closing the output stream. Therefore any data buffered within it before being written out to disk will be lost.

You could use a try-with-resources statement to close the stream automatically - or you could just use:

// Alternatives, pass in the `File` to copy to, or make the method generally
// more flexible in other ways.
Files.copy(file.toPath(), Paths.get("/Users/default/Desktop/fotos/test.png"));

As an aside, it's unusual to call System.exit in a method like this - it's not like the method is saveFileAndTerminateApplication. Likewise your exception "handling" isn't ideal. I would basically let the exception bubble up, i.e. declare that your method throws it. Currently, there are three possibilities:

  • Everything works, and the app terminates
  • The copy works, but System.exit throws an unchecked exception
  • The copy fails, so the method returns - the caller could infer that something went wrong, but with no idea what

That doesn't sound like an obvious set of results to me...

Upvotes: 4

Related Questions