Writing output from console in java to text file

Question

I'd like to show my Console's output in a text file.

public static void main(String [ ] args){
    DataFilter df = new DataFilter();   
    df.displayCategorizedList();
    PrintStream out;
    try {
        out = new PrintStream(new FileOutputStream("C:\\test1.txt", true));
        System.setOut(out);
    } catch (FileNotFoundException e) {
        // TODO Auto-generated catch block
        e.printStackTrace();
    }

}

I get my result correctly on the screen but not result in the textfile ? the test file is genereted but it is empty??

does df.displayCategorizedList(); print to stdout? Then you should probably move it behind System.setOut() — Andreas Fester
– Andreas Fester, Commented Apr 5, 2013 at 7:26
This topic seems to have been dealt with fairly thoroughly over here. — Steven
– Steven, Commented Apr 5, 2013 at 7:27
@SaharSj He means that the output seems to be done before you call setOut(). Just move df.displayCategorizedList(); below your try/catch block. — Axel
– Axel, Commented Apr 5, 2013 at 7:29

giorashc · Accepted Answer · 2013-04-05 07:26:37Z

5

You should print to "console" after you have set the system output stream into a file.

    DataFilter df = new DataFilter();   
    PrintStream out;
    try {
        out = new PrintStream(new FileOutputStream("C:\\test1.txt", true));
        System.setOut(out);
        df.displayCategorizedList();
    } catch (FileNotFoundException e) {
        // TODO Auto-generated catch block
        e.printStackTrace();
    } finally {
        if (out != null)
            out.close();
    }

Also use a finally block to always close the stream otherwise data might not be flushed to the file.

answered Apr 5, 2013 at 7:26

giorashc

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1 Comment

m suresh Over a year ago

you set the o/p stream to file then save in c folder

Olimpiu POP · Accepted Answer · 2013-04-05 07:34:23Z

0

I would suggest the following approach:

public static void main(String [ ] args){
    DataFilter df = new DataFilter();   
    try (PrintStream out = new PrintStream(new FileOutputStream("d:\\file.txt", true))) {
          System.setOut(out);
          df.displayCategorizedList();
    } catch (FileNotFoundException e) {
        System.err.println(String.format("An error %s occurred!", e.getMessage()));
    }
}

This is using the JDK 7 try-with-resources feature - meaning that it deals with exceptions (like FileNotFoundException) that you have and it also closes the resources (instead of the finally block).

If you cannot use JDK 7, use one of the approaches suggested in the other responses.

answered Apr 5, 2013 at 7:34

Olimpiu POP

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