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position,limit，准备接受数据
bytes = client.read(buffer); // 从通道中读数据到缓冲中，返回读取得字节数
if(bytes >= 0)
{
buffer.flip(); // 准备将缓冲中的数据写回到通道中
client.write(buffer);  // 数据写回到通道中
}
else if(bytes < 0)
{ // 如果返回小于零的值代表读到了流的末尾
clients.remove(client);
// 通道关闭时，选择键也被取消
client.close();
}
}
}
}
}

public void registerClient(SocketChannel client) throws IOException
{// 配置和注册代表客户连接的通道对象
client.configureBlocking(false);  // 设置此通道使用非阻塞模式
client.register(readSelector, SelectionKey.OP_READ); // 将这个通道注册到选择器上
clients.add(client); //保存这个通道对象
}
public void listen() throws IOException
{ //服务器开始监听端口，提供服务
ServerSocket socket;
SocketChannel client;
channel = ServerSocketChannel.open(); // 打开通道
socket = channel.socket();   //得到与通到相关的socket对象
socket.bind(new InetSocketAddress(port), 10);   //将scoket榜定在制定的端口上
//配置通到使用非阻塞模式，在非阻塞模式下，可以编写多道程序同时避免使用复杂的多线程
channel.configureBlocking(false);
try
{
while(true)
{//     与通常的程序不同，这里使用channel.accpet()接受客户端连接请求，而不是在socket对象上调用accept(),这里在调用accept()方法时如果通道配置为非阻塞模式,那么accept()方法立即返回null，并不阻塞
client = channel.accept();
if(client != null)
{
registerClient(client); // 注册客户信息
}
serviceClients();  // 为以连接的客户服务
}
}
finally
{
socket.close(); // 关闭socket，关闭socket会同时关闭与此socket关联的通道
}
}
public static void main(String[] args) throws IOException
{
System.out.println("服务器启动");
SelectorServer server = new SelectorServer(SelectorServer.DEFAULT_SERVERPORT);
server.listen(); //服务器开始监听端口，提供服务

}

}

package com.vista.Server;

import java.io.BufferedWriter;
import java.io.FileInputStream;
import java.io.IOException;
import java.io.OutputStreamWriter;
import java.io.PrintWriter;
import java.net.InetSocketAddress;
import java.net.ServerSocket;
import java.nio.ByteBuffer;
import java.nio.CharBuffer;
import java.nio.channels.FileChannel;
import java.nio.channels.SelectionKey;
import java.nio.channels.Selector;
import java.nio.channels.ServerSocketChannel;
import java.nio.channels.SocketChannel;
import java.nio.charset.Charset;
import java.nio.charset.CharsetDecoder;
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 static String DEFAULT_CHARSET = "GB2312";//默认码集
private static String DEFAULT_FILENAME = "bigfile.dat";
private ServerSocketChannel channel;
private LinkedList<SocketChannel> clients;
private Selector selector;//选择器
private ByteBuffer buffer;//字节缓冲区
private int port;
private Charset charset;//字符集
private CharsetDecoder decoder;//解码器

public SelectorServer(int port) throws IOException
{
this.port = port;
this.clients = new LinkedList<SocketChannel>();
this.channel = null;
this.selector = Selector.open();//打开选择器
this.buffer = ByteBuffer.allocate(DEFAULT_BUFFERSIZE);
this.charset = Charset.forName(DEFAULT_CHARSET);
this.decoder = this.charset.newDecoder();

}

private class HandleClient
{
private String strGreeting = "welcome to VistaQQ";
public HandleClient() throws IOException
{
}
public String readBlock()
{//读块数据
return this.strGreeting;
}
public void close()
{

}
}

protected void handleKey(SelectionKey key) throws IOException
{//处理事件
if (key.isAcceptable())
{ // 接收请求
ServerSocketChannel server = (ServerSocketChannel) key.channel();//取出对应的服务器通道
SocketChannel channel = server.accept();
channel.configureBlocking(false);
channel.register(selector, SelectionKey.OP_READ);//客户socket通道注册读操作
}
else if (key.isReadable())
{ // 读信息
SocketChannel channel = (SocketChannel) key.channel();
int count = channel.read(this.buffer);
if (count > 0)
{
this.buffer.flip();
CharBuffer charBuffer = decoder.decode(this.buffer);
System.out.println("Client >>" + charBuffer.toString());
SelectionKey wKey = channel.register(selector,
SelectionKey.OP_WRITE);//为客户sockt通道注册写操作
wKey.attach(new HandleClient());
}
else
{//客户已经断开
channel.close();
}
this.buffer.clear();//清空缓冲区
}
else if (key.isWritable())
{ // 写事件
SocketChannel channel = (SocketChannel) key.channel();
HandleClient handle = (HandleClient) key.attachment();//取出处理者
ByteBuffer block = ByteBuffer.wrap(handle.readBlock().getBytes());
channel.write(block);
// channel.socket().getInputStream().(block);
//              PrintWriter out = new PrintWriter(new BufferedWriter(new OutputStreamWriter(
//                        channel.socket().getOutputStream())), true);
//              out.write(block.toString());

}

}
public void listen() throws IOException
{ //服务器开始监听端口，提供服务
ServerSocket socket;
channel = ServerSocketChannel.open(); // 打开通道
socket = channel.socket();   //得到与通到相关的socket对象
socket.bind(new InetSocketAddress(port));   //将scoket榜定在制定的端口上
//配置通到使用非阻塞模式，在非阻塞模式下，可以编写多道程序同时避免使用复杂的多线程
channel.configureBlocking(false);
channel.register(selector, SelectionKey.OP_ACCEPT);
try
{
while(true)
{//     与通常的程序不同，这里使用channel.accpet()接受客户端连接请求，而不是在socket对象上调用accept(),这里在调用accept()方法时如果通道配置为非阻塞模式,那么accept()方法立即返回null，并不阻塞
this.selector.select();
Iterator iter = this.selector.selectedKeys().iterator();
while(iter.hasNext())
{
SelectionKey key = (SelectionKey)iter.next();
iter.remove();
this.handleKey(key);

}
}
}
catch(IOException ex)
{
ex.printStackTrace();
}
}
public static void main(String[] args) throws IOException
{
System.out.println("服务器启动");
SelectorServer server = new SelectorServer(SelectorServer.DEFAULT_SERVERPORT);
server.listen(); //服务器开始监听端口，提供服务
}

}