Java6学习笔记70—— 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);
}
}
}