Get file position

Posted on 2004-08-30
Last Modified: 2010-05-18

I'm writing a text file. For reasons of convienience I use the PrintWriter object.

My problem is that at certain points during the file write operation I need to know
the current file pointer position. If this was a RandomAccessFile I would simply
do getFilePointer() method.

How do I know which byte position I'm at ?   Is there another way of doing this ?

Question by:kxix
LVL 24

Expert Comment

ID: 11930044
You can by using a "channel".
LVL 35

Expert Comment

ID: 11930061
How are you writing the data? Character by character? If yes then you coudl use a counter and count how many characters you write and then save the position somewhere. If you write a String then count the length of the string and get the last position every time. Do likewise for the other constructors (byte array or String with offsets).
LVL 35

Expert Comment

ID: 11930066
> constructors (byte array or String with offsets).

should be

write method signatures (byte array or String with offsets).
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LVL 24

Accepted Solution

sciuriware earned 250 total points
ID: 11930074
Example I used for input monitoring:

import java.nio.channels.FileChannel;

         FileInputStream fi = new FileInputStream(source);
         FileChannel fic = fi.getChannel();
               position = fic.position();

And so on.

LVL 86

Expert Comment

ID: 11930142
>>I need to know the current file pointer position.

Why, may we ask?

Author Comment

ID: 11949152
The simplest answer seems to be to use a Channel as suggested by "sciuriware".
I therefore accept this answer.
LVL 14

Expert Comment

ID: 11949161
>> The simplest answer seems to be to use a Channel as suggested by "sciuriware".

Then we you gave just 'C' to he or she ???
LVL 24

Expert Comment

ID: 11949269
Correct English would be:

"Then, why did you just give 'C' to him or her?"

And his opinion is .......  I don't care too much.


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