Converting File to Bytes and reading it in loop

[Gangrade Sumit]

Hi,

I have somehow got stuck in this -

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Each time I need to read only max 0f 100 bytes from a file and then need to convert bytes to String and do some processing.

Then I want to read next 100 bytes. this needs to go on till EOF.

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Thanks in Advance
Sumit

[clio katz]

if you are using 1.4.x and are dealing with files of size that won't blow you memory, you could read the file into a ByteBuffer and use a byte array (of size 10) to fetch the intermediate chunks.

eg

        String someFile = ... 
 
        byte [] buf;
        byte [] chunk = new byte[10];
 
        try {
            
            // get length
            int len = (int)(new File(someFile).length());
            
            // read entire file
            FileInputStream fis =
                new FileInputStream(someFile);
                
            buf = new byte[len];
            
            fis.read(buf);
            fis.close();
            
      } catch (IOException e) {
            System.out.println("Error: "+e.toString());
            System.exit(-1);
      }
      
      ByteBuffer wBuf = ByteBuffer.wrap(buf);
 
      try {
          do {
              wBuf.get(chunk);
              .
              .
              .
          }while ( condition ... );
 
      } catch (BufferUnderflowException  e) {
            // done
      }
 

I use a variation of this style of code for library IO functions. Note that the example I'm using is adapted from a tip in Sun Performance Tips - you can find more variations on the same there.

hth
[ May 15, 2004: Message edited by: clio katz ]