How to append to existing file

Question

I am trying to redirect the console input to a file. Problem is that every time i create a file it overwrites it or creates new files if I select the name of file to include unix timestamp. I saw similar questions here but I am not sure which approach or class to use.

    PrintStream out;
    PrintStream oldout = new PrintStream(System.out);

    try {
        out = new PrintStream(
                new FileOutputStream(
                        workFolder + File.separator + "output" + Instant.now().getEpochSecond() + ".txt"));


         System.setOut(out);
    } catch (FileNotFoundException e) {
        // TODO Auto-generated catch block
        e.printStackTrace();
    }
System.setOut(oldout);

So if there isn't a file to create it, but if there is already a file to just append new data, but not overwrite or create new files.

There's a pretty current guide available at https://www.baeldung.com/java-append-to-file — Ryan Dawson, Aug 07 '18 at 11:33

score -1 · Accepted Answer · answered Aug 07 '18 at 11:34

As per Java docs

public FileOutputStream(String name,
                boolean append)
                 throws FileNotFoundException

Parameters: name - the system-dependent file name

append - if true, then bytes will be written to the end of the file rather than the beginning

There is a constructor which allows passing the boolean value which decides whether to append the data in file or not.

You can use it.

How to append to existing file

1 Answers1