技术贴：java nio的示例

package com.vista.Server;
import java.io.IOException;
import java.net.InetSocketAddress;
import java.net.ServerSocket;
import java.nio.ByteBuffer;
import java.nio.channels.SelectionKey;
import java.nio.channels.Selector;
import java.nio.channels.ServerSocketChannel;
import java.nio.channels.SocketChannel;
import java.util.Iterator;
import java.util.LinkedList;
import java.util.Set;
public class SelectorServer
{
private static int DEFAULT_SERVERPORT = 6018;//默认端口
private static int DEFAULT_BUFFERSIZE = 1024;//默认缓冲区大小为1024字节
private ServerSocketChannel channel;
private LinkedList<SocketChannel> clients;
private Selector readSelector;
private ByteBuffer buffer;//字节缓冲区
private int port;

public SelectorServer(int port) throws IOException
{
this.port = port;
this.clients = new LinkedList<SocketChannel>();
this.channel = null;
this.readSelector = Selector.open();//打开选择器
this.buffer = ByteBuffer.allocate(DEFAULT_BUFFERSIZE);
}
// 服务器程序在服务循环中调用sericeClients()方法为已接受的客户服务
public void serviceClients()throws IOException
{
Set keys;
Iterator it;
SelectionKey key;
SocketChannel client;
// 在readSelector上调用select()方法，参数1代表如果调用select的时候 那么阻塞最多1秒钟等待可用的客户端连接
if(readSelector.select(1) > 0)
{
keys = readSelector.selectedKeys(); // 取得代表端通道的键集合
it = keys.iterator();
// 遍历，为每一个客户服务
while(it.hasNext())
{
key = (SelectionKey)it.next();
if(key.isReadable())
{ // 如果通道可读，那么读此通道到buffer中
int bytes;
client = (SocketChannel)key.channel();// 取得键对应的通道
buffer.clear(); // 清空缓冲区中的内容，设置好positi