【Java学习笔记】FileChannel的学习

作者：gnuhpc
出处：http://www.cnblogs.com/gnuhpc/

定义了各种通道，这些通道表示到能够执行 I/O 操作的实体（如文件 和套接字）的连接；定义了用于多路复用的、非阻塞 I/O 操作的选择器。

写文件

import java.io.FileOutputStream;
import java.io.IOException;
import java.nio.ByteBuffer;
import java.nio.CharBuffer;
import java.nio.channels.FileChannel;
public class NioBlockout {
    public static void main(String arg[]) {
        try {
            FileOutputStream fos = new FileOutputStream("nioblock");
            FileChannel channel = fos.getChannel();
            ByteBuffer bytebuffer = ByteBuffer.allocate(20);
            CharBuffer charbuffer = bytebuffer.asCharBuffer();
            charbuffer.put("ABCDEFGHI");
            channel.position(20);
            channel.write(bytebuffer);
            channel.close();
        } catch(IOException e) {
            System.out.println(e);
        }
    }
}

文件buffer

import java.io.IOException;
import java.io.RandomAccessFile;
import java.nio.channels.FileChannel;
import java.nio.channels.FileChannel.MapMode;
import java.nio.MappedByteBuffer;
import java.nio.CharBuffer;
public class NioMap {
    public static void main(String arg[]) {
        try {
            RandomAccessFile raf = new RandomAccessFile("nioblock","rw");
            FileChannel channel = raf.getChannel();
            MappedByteBuffer bytebuffer = channel.map(
                    FileChannel.MapMode.READ_WRITE,
                    20,18); // position and size
            CharBuffer charbuffer = bytebuffer.asCharBuffer();
            bytebuffer.load();
            char ch = charbuffer.get(3);
            System.out.println("Character: " + ch);
            charbuffer.put(3,'X');
            channel.close();
        } catch(IOException e) {
            System.out.println(e);
        }
    }
}

作者：gnuhpc
出处：http://www.cnblogs.com/gnuhpc/