Admin: 1 версия

2010-06-01T06:04:06Z

1 версия

в 18:01, 31 мая 2010

2010-05-31T18:01:43Z

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== Map FileChannel to MappedByteBuffer ==



<source lang="java">

import java.io.FileInputStream;
import java.nio.MappedByteBuffer;
import java.nio.channels.FileChannel;
public class Main {
public static void main(String args[]) throws Exception {
String filename = args[0];
int start = 10;
int length = 20;
FileInputStream fin = new FileInputStream(filename);
FileChannel finc = fin.getChannel();
MappedByteBuffer mbb = finc.map(FileChannel.MapMode.READ_ONLY, start, length);
for (int i = 0; i < length; ++i) {
System.out.println(mbb.get(i);
}
fin.close();
}
}

</source>



== Persisting Changes to a Memory-Mapped ByteBuffer ==



<source lang="java">

import java.io.File;
import java.io.RandomAccessFile;
import java.nio.MappedByteBuffer;
import java.nio.channels.FileChannel;
public class Main {
public static void main(String[] argv) throws Exception {
File file = new File("filename");
FileChannel channel = new RandomAccessFile(file, "rw").getChannel();
MappedByteBuffer buf = channel.map(FileChannel.MapMode.READ_WRITE, 0, (int) channel.size());
buf.put(0, (byte) 0xFF);
buf.force();
channel.close();
}
}

</source>



== Read file upside/down with RandomAccessFile ==



<source lang="java">

import java.io.RandomAccessFile;
import java.nio.MappedByteBuffer;
import java.nio.channels.FileChannel;
public class Main {
public static void main(String[] args) throws Exception {
RandomAccessFile f = new RandomAccessFile("hello.txt", "rw");
FileChannel fc = f.getChannel();
MappedByteBuffer mbb = fc.map(FileChannel.MapMode.READ_WRITE, 0, f.length());
int len = (int) f.length();
for (int i = 0, j = len - 1; i < j; i++, j--) {
byte b = mbb.get(i);
mbb.put(i, mbb.get(j));
mbb.put(j, b);
}
fc.close();
}
}

</source>

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Java/File Input Output/MappedByteBuffer - История изменений

Admin: 1 версия

в 18:01, 31 мая 2010