【Java学习笔记】FileChannel的学习

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); 
        } 
    } 
}

本文转自gnuhpc博客园博客，原文链接：http://www.cnblogs.com/gnuhpc/archive/2012/12/17/2822311.html，如需转载请自行联系原作者