32 lines
895 B
Java
32 lines
895 B
Java
// newio/LargeMappedFiles.java
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// (c)2020 MindView LLC: see Copyright.txt
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// We make no guarantees that this code is fit for any purpose.
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// Visit http://OnJava8.com for more book information.
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// Creating a very large file using mapping
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import java.nio.*;
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import java.nio.channels.*;
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import java.io.*;
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public class LargeMappedFiles {
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static int length = 0x8000000; // 128 MB
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public static void
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main(String[] args) throws Exception {
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try(
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RandomAccessFile tdat =
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new RandomAccessFile("test.dat", "rw")
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) {
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MappedByteBuffer out = tdat.getChannel().map(
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FileChannel.MapMode.READ_WRITE, 0, length);
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for(int i = 0; i < length; i++)
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out.put((byte)'x');
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System.out.println("Finished writing");
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for(int i = length/2; i < length/2 + 6; i++)
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System.out.print((char)out.get(i));
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}
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}
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}
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/* Output:
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Finished writing
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xxxxxx
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*/
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