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 }}

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