Creating a very large file using mapping : Input Output Stream « File Input Output « Java

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Creating a very large file using mapping

// : c12:LargeMappedFiles.java // Creating a very large file using mapping. // {RunByHand} // {Clean: test.dat} // From 'Thinking in Java, 3rd ed.' (c) Bruce Eckel 2002 // www.BruceEckel.com. See copyright notice in CopyRight.txt. import java.io.RandomAccessFile; import java.nio.MappedByteBuffer; import java.nio.channels.FileChannel; publicclass LargeMappedFiles { staticint length = 0x8FFFFFF; // 128 Mb publicstaticvoid main(String[] args) throws Exception { MappedByteBuffer out = new RandomAccessFile("test.dat", "rw") .getChannel().map(FileChannel.MapMode.READ_WRITE, 0, length); for (int i = 0; i < length; i++) out.put((byte) 'x'); System.out.println("Finished writing"); for (int i = length / 2; i < length / 2 + 6; i++) System.out.print((char) out.get(i)); } } ///:~ 

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