问题
My program is currently using
FileOutputStream output = new FileOutputStream("output", true);
A while loop creates the output file if it is not yet created and appends some data to this file for every iteration of the while loop using
output.write(data).
This is fine and is what I want.
If I run the program again the file just doubles in size as it appends the exact information to the end of the file. This is not what I want. I would like to overwrite the file if I run the program again.
回答1:
This documentation suggests that the parameter you're passing is the append parameter.
the signature looks like the following
FileOutputStream(File file, boolean append)
You should set that parameter to false since you don't want to append.
FileOutputStream output = new FileOutputStream("output", false);
回答2:
I would like to overwrite the file if I run the program again.
Pass false as 2nd argument, to set append to false:
FileOutputStream output = new FileOutputStream("output", false);
Check out the constructor documentation:
If the second argument is true, then bytes will be written to the end of the file rather than the beginning.
回答3:
Or you could just delete the file if it's there, and then always create it and job done.
来源：https://stackoverflow.com/questions/17957849/java-overwriting-an-existing-output-file