MappedByteBufferTest.java

package com.learnjava.io.nio;

import java.io.RandomAccessFile;
import java.nio.MappedByteBuffer;
import java.nio.channels.FileChannel;

/**
 * @author LuoHaiYang
 */
public class MappedByteBufferTest {
    public static void main(String[] args) throws Exception {

        RandomAccessFile randomAccessFile = new RandomAccessFile("1.txt", "rw");

        // get channel
        FileChannel channel = randomAccessFile.getChannel();

        MappedByteBuffer mappedByteBuffer = channel.map(FileChannel.MapMode.READ_WRITE, 0, 5);

        mappedByteBuffer.put(0, (byte)'H');
        mappedByteBuffer.put(3, (byte)'9');

        // IndexOutOfBoundsException
        mappedByteBuffer.put(5, (byte)'Y');

        randomAccessFile.close();
        System.out.println("change success");
    }
}