Write the console output over several runs to a text file

Question

My question is related to this one. However, I am looking for a way to append the text file over several runs. is there a way to write console output to a text file without erasing the old runs information? I am working on 30+ classes and it would be tedious to change System.out.println statements so I prefer sticking with the System.setOut solution.

I have the following code based on @Mac answer

   PrintStream out = new PrintStream(new FileOutputStream("aa.txt"),true);
   System.setOut(out);

but the file aa.txtdoes not append the results, am I missing something here?

3 great answers within minutes is really a great surprise. Thanks all — seteropere, Jul 13 '13 at 08:49
No, it is NOT a duplicate of that question. Read carefully - it is asking something quite different. — Dawood ibn Kareem, Jul 13 '13 at 09:17
Did you try `new PrintStream(new FileOutputStream("aa.txt",true))` ? As I said in my comment on Mac's answer, he/she had the parentheses wrong. — Dawood ibn Kareem, Jul 13 '13 at 09:19

Dawood ibn Kareem · Accepted Answer · 2013-07-13T09:20:27.097

5

When you create a FileWriter or FileOutputStream for your file, pass true as a second argument to the constructor of the FileWriter or FileOutputStream.

FileWriter(File file, boolean append)

edited Jul 13 '13 at 09:20

answered Jul 13 '13 at 08:44

Dawood ibn Kareem

77,785
15
98
110

I am using PrintStream but it doesn't append – seteropere Jul 13 '13 at 09:07
Paste your code, so we can let you know what you have done wrong. – Dawood ibn Kareem Jul 13 '13 at 09:13

score 3 · Answer 2 · answered Jul 13 '13 at 08:44

3

FileWriter and FileOutputStream provide a constructor with an append flag. Just modify the referenced code accordingly

answered Jul 13 '13 at 08:44

Michael Butscher

10,028
4
24
25

score 3 · Answer 3 · answered Jul 13 '13 at 08:44

3

You should use:

PrintStream out = new PrintStream(new FileOutputStream("output.txt"),true);
System.setOut(out);

answered Jul 13 '13 at 08:44

Mac

1,711
3
12
26

1

Are you sure? It seems to me that you may've put the parentheses in the wrong places. – Dawood ibn Kareem Jul 13 '13 at 08:47
@DavidWallace copy pasted the code and it works :) – seteropere Jul 13 '13 at 08:48
1

@seteropere But not as desired (no append) – Michael Butscher Jul 13 '13 at 08:54

Write the console output over several runs to a text file

3 Answers3