有一本小书，叫<java nio>， 2002年的中文版PDF。

可以看看，尽管是一本历史感很强的书，

讲解还是很细致的。

由此进深入nio2的话，

那java io的秘密，

就全部清晰了。

package com.ronsoft.books.nio.buffers;import java.nio.CharBuffer;import java.nio.Buffer;import java.nio.ByteBuffer;import java.nio.ByteOrder;public class BufferFillDrain {	public static void main(String[] args) throws Exception {		// TODO Auto-generated method stub		CharBuffer buffer = CharBuffer.allocate(100);		while (fillBuffer(buffer)) {			buffer.flip();			drainBuffer(buffer);			buffer.clear();					}				ByteBuffer byteBuffer = ByteBuffer.allocate(7).order(ByteOrder.BIG_ENDIAN);		CharBuffer charBuffer = byteBuffer.asCharBuffer();		byteBuffer.put(0, (byte)0);		byteBuffer.put(1, (byte)'H');		byteBuffer.put(2, (byte)0);		byteBuffer.put(3, (byte)'i');		byteBuffer.put(4, (byte)0);		byteBuffer.put(5, (byte)'!');		byteBuffer.put(6, (byte)0);		println(byteBuffer);		println(charBuffer);	}		private static void drainBuffer(CharBuffer buffer) {		while (buffer.hasRemaining()) {			System.out.print(buffer.get());		}		System.out.println("");	}		private static boolean fillBuffer(CharBuffer buffer) {		if (index >= strings.length) {			return (false);		}		String string = strings[index++];		for (int i = 0; i < string.length(); i++) {			buffer.put(string.charAt(i));		}		return (true);	}		private static int index = 0;	private static String []strings = {			"A random string value",			"The product of an infinite number of monkeys",			"Hey hey we're the Monkees",			"Opening act for the Monkees: Jimi Hendrix",			"'Scuse me while I kill this fly",			"Help Me! Help Me!",	};			private static void println(Buffer buffer) {		System.out.println("post=" + buffer.position()				+ ", limit=" + buffer.limit()				+ ", capacity=" + buffer.capacity()				+ ": '" + buffer.toString() + "'");	}}

A random string valueThe product of an infinite number of monkeysHey hey we're the MonkeesOpening act for the Monkees: Jimi Hendrix'Scuse me while I kill this flyHelp Me! Help Me!post=0, limit=7, capacity=7: 'java.nio.HeapByteBuffer[pos=0 lim=7 cap=7]'post=0, limit=3, capacity=3: 'Hi!'