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Read from file without loading into the JVM?

Derek White
Greenhorn

Joined: Jul 24, 2008
Posts: 14
Is it possible to read/write (using a stream maybe?) from a file without actually loading the whole thing into the JVM?

I am used to loading the whole file into memory but I realize if a file becomes to large it will hog resources. Is there any way I can maintain low memory usage and the ability to constantly read/write data?
Paul Clapham
Bartender

Joined: Oct 14, 2005
Posts: 18541
    
    8

Of course. Simply read part of the file, process it, then throw it away and read the next part of the file.

A common example of this is where you read a text file one line at a time and process each line separately.
Rob Spoor
Sheriff

Joined: Oct 27, 2005
Posts: 19654
    
  18

By default, FileInputStream and FileReader don't store more than a few kilobytes. Just keep on calling on of the read methods (or readLine() if you've wrapped them in a BufferedReader) and process the bytes / chars / lines directly instead of storing them.


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