Java - appending to Excel file with FileOutputStream

Question

This code appends to an already created Excel file:

FileOutputStream fileOut = new FileOutputStream("c:\\Decrypted.xls");

What can we add / modify so that Decrypted.xls should be created if not already created and appended if already created?

There isn't anything specific to Excel files. That could just as well be edited out. — uckelman
– uckelman, Commented Nov 25, 2009 at 19:05
I wonder what the purpose of this is? Somehow I doubt that the result will be a working, bigger Excel file with more data in it. — Carl Smotricz
– Carl Smotricz, Commented Nov 25, 2009 at 19:11

uckelman · Accepted Answer · 2009-11-25 18:59:26Z

1

You want the FileOutputStream(File file, boolean append) constructor for switching on whether you truncate or append.

answered Nov 25, 2009 at 18:59

uckelman

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Comments

delfuego · Accepted Answer · 2009-11-25 19:07:53Z

0

According to the Javadocs for the String-accepting constructor of FileOutputStream, rover12, if the file doesn't already exist then it's created. Are you not seeing this behavior?

(And as others have mentioned, be sure to use the constructor that takes the second boolean argument so you can specify that you want to append the file if it already exists...)

answered Nov 25, 2009 at 18:58

delfuego

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no i am not seeing this behaviour .. if i delete the already existing Decrypted.xls i get an error compliling that says .. file does not exist

Andreas Dolk · Accepted Answer · 2009-11-25 19:00:29Z

0

Use the constructor:

FileOutputStream fileOut = new FileOutputStream("c:\\Decrypted.xls", true);

to append to an existing file, if it doesn't exist. Your example will overwrite the existing one.

answered Nov 25, 2009 at 19:00

Andreas Dolk

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