The system cannot find the path specified with FileWriter

Question

I have this code:

private static void saveMetricsToCSV(String fileName, double[] metrics) {
        try {
            FileWriter fWriter = new FileWriter(
                    System.getProperty("user.dir") + "\\output\\" +
                    fileTimestamp + "_" + fileDBSize + "-" + fileName + ".csv"
            );

            BufferedWriter csvFile = new BufferedWriter(fWriter);

            for(int i = 0; i < 4; i++) {
                for(int j = 0; j < 5; j++) {
                    csvFile.write(String.format("%,10f;", metrics[i+j]));
                }

                csvFile.write(System.getProperty("line.separator"));
            }

            csvFile.close();
        } catch(IOException e) {
            System.out.println(e.getMessage());
        }
    }

But I get this error:

C:\Users\Nazgulled\Documents\Workspace\Só Amigos\output\1274715228419_5000-List-ImportDatabase.csv (The system cannot find the path specified)

Any idea why?

I'm using NetBeans on Windows 7 if it matters...

Answer 1

In general, a non existent file will be created by Java only if the parent directory exists. You should check/create the directory tree:

  String filenameFullNoPath = fileTimestamp + "_"  + fileDBSize + "-" 
        + fileName + ".csv";
  File myFile =  new File(System.getProperty("user.dir")  + File.separator 
        + "output" + File.separator + filenameFullNoPath);
  File parentDir = myFile.getParentFile();
  if(! parentDir.exists()) 
      parentDir.mkdirs(); // create parent dir and ancestors if necessary
  // FileWriter does not allow to specify charset, better use this:
  Writer w = new OutputStreamWriter(new FileOutputStream(myFile),charset);

Answer 2

You can use getParentFile (Java Doc) to make sure that the parent directory exists. The following will check that the parent directory exists, and create it if it doesn't.

File myFile =  new File(fileName);
if(!myFile.getParentFile.exists()) {
     myFile.getParentFile.mkdirs();
}