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首先我们必须了解NIO的一些基本概念
channel：是NIO中的一个通道，类似我们说的流。---管道
Buffer：理解为byte数组。与channel交流。----水流
Selector：有一个SelectableChancel实现，用线程管理------选择器
package pattern.nio;import java.io.IOException;import java.net.InetAddress;import java.net.InetSocketAddress;import java.net.ServerSocket;import java.net.Socket;import java.nio.ByteBuffer;import java.nio.channels.*;import java.nio.channels.spi.SelectorProvider;import java.util.*;import java.util.concurrent.ExecutorService;import java.util.concurrent.Executors;/** * Created by ycy on 16/1/19. */public class NioServer { //选择器 private Selector selector; //线程池 private ExecutorService tp = Executors.newCachedThreadPool(); //给定大小的map public static Map time_stat = new HashMap (10240); public void startServer() throws Exception { //1'由selectorPrivider返回一个创建者,并打开一个选择器 selector = SelectorProvider.provider().openSelector(); //2'打开套接字通道 ServerSocketChannel ssc = ServerSocketChannel.open(); //block - 如果为 true，则此通道将被置于阻塞模式；如果为 false，则此通道将被置于非阻塞模式 ssc.configureBlocking(false); InetSocketAddress isa = new InetSocketAddress(65500); // InetSocketAddress isa=new InetSocketAddress(8000); //获取与此通道关联的服务器套接字。将 ServerSocket 绑定到特定地址（IP 地址和端口号） ssc.socket().bind(isa); //将通道注册到选择器, SelectionKey accpetKey = ssc.register(selector, SelectionKey.OP_ACCEPT); try { for (; ; ) { selector.select();//消费阻塞 Set readykeys = selector.selectedKeys();//获取已经准备好的keys Iterator i = readykeys.iterator();//迭代 long e = 0; while (i.hasNext()) { SelectionKey sk = (SelectionKey) i.next(); i.remove();//必须消除,防止重复消费 if (sk.isAcceptable()) { doAccept(sk);//如果为接受状态,接受 } else if (sk.isValid() && sk.isReadable()) {//如果是可读 if (!time_stat.containsKey(((SocketChannel) sk.channel()).socket())) { //将socket方法如map time_stat.put(((SocketChannel) sk.channel()).socket(), System.currentTimeMillis());//增加一个时间戳 //读取 doRead(sk); } } else if (sk.isValid() && sk.isWritable()) { //写 doWrite(sk); e = System.currentTimeMillis(); long b = time_stat.remove(((SocketChannel) sk.channel()).socket()); System.out.println("spend:" + (e - b) + "ms");//输入处理写入耗时 } } } } catch (ClosedSelectorException e) { System.out.println("外面捕捉不做事"); } } /* 与客户端建立连接 */ private void doAccept(SelectionKey sk) { try { ServerSocketChannel server = (ServerSocketChannel) sk.channel(); SocketChannel clientChannel; clientChannel = server.accept();//生成一个channel表示与客户端通信 clientChannel.configureBlocking(false);//非阻塞模式 //Register this channel for reading SelectionKey clientKey = clientChannel.register(selector, SelectionKey.OP_READ); //Allocate an Echoclient instance adn attach it to this selction key EchoClient echoClient = new EchoClient();//回复给客服端口的全部信息 clientKey.attach(echoClient);//附加实例,整个连接共享实例 InetAddress clientAddress = clientChannel.socket().getInetAddress(); System.out.println("Acceprted connection form " + clientAddress.getHostAddress() + ".") ; } catch (Exception e) { e.printStackTrace(); } } //执行读得操作 private void doRead(SelectionKey sk) { SocketChannel channel = (SocketChannel) sk.channel(); ByteBuffer bb = ByteBuffer.allocate(8192); int len; try { len = channel.read(bb); if (len < 0) { disconnect(sk); return; } } catch (Exception e) { System.out.println("faild to read from client"); e.printStackTrace(); disconnect(sk); return; } bb.flip(); tp.execute(new HanldeMsg(sk, bb)); } private void disconnect(SelectionKey sk) { try { SocketChannel channel = (SocketChannel) sk.channel(); channel.close(); //sk.cancel(); sk.selector().close(); } catch (IOException e) { e.printStackTrace(); } } //执行写操作 private void doWrite(SelectionKey sk) { SocketChannel channel = (SocketChannel) sk.channel(); EchoClient echoClient = (EchoClient) sk.attachment(); LinkedList outq = echoClient.getOutputQuquq(); ByteBuffer bb = outq.getLast(); try { int len = channel.write(bb); if (len == -1) { disconnect(sk); return; } if (bb.remaining() == 0) { //已经完成 outq.removeLast(); } } catch (Exception e) { System.out.println("Faild to write to client"); e.printStackTrace(); disconnect(sk); } if (outq.size() == 0) {//很重要 sk.interestOps(SelectionKey.OP_READ); } } /内部匿名类/ class EchoClient { private LinkedList outq; EchoClient() { outq = new LinkedList (); } public LinkedList getOutputQuquq() { return outq; } public void enqueue(ByteBuffer bb) { outq.addFirst(bb); } } //将接受的数据压入EchClient,需要处理业务在这u处理,处理完成之后重新注册事件op_write class HanldeMsg implements Runnable { SelectionKey sk; ByteBuffer bb; public HanldeMsg(SelectionKey sk, ByteBuffer bb) { this.sk = sk; this.bb = bb; } public void run() { EchoClient echoClient = (EchoClient) sk.attachment(); echoClient.enqueue(bb); sk.interestOps(SelectionKey.OP_READ | SelectionKey.OP_WRITE); //强迫selector立即返回 selector.wakeup(); } }} package pattern.nio;/** * Created by ycy on 16/1/20. */public class NioMain { public static void main(String[] args) throws Exception { NioServer nioServer=new NioServer(); nioServer.startServer(); }} package pattern.nio;import java.io.IOException;import java.net.InetSocketAddress;import java.nio.ByteBuffer;import java.nio.channels.SelectionKey;import java.nio.channels.Selector;import java.nio.channels.SocketChannel;import java.nio.channels.spi.SelectorProvider;import java.util.Iterator;/** * Created by ycy on 16/1/20. */public class NioClient { private Selector selector; public void init(String ip,int port) throws IOException { SocketChannel channel=SocketChannel.open(); channel.configureBlocking(false); this.selector= SelectorProvider.provider().openSelector(); channel.connect(new InetSocketAddress(ip,port)); channel.register(selector,SelectionKey.OP_CONNECT); } public void working() throws IOException { while (true){ if (!selector.isOpen()){ break; } selector.select(); Iterator ite=this.selector.selectedKeys().iterator(); while (ite.hasNext()){ SelectionKey key=ite.next(); ite.remove(); //连接事件 if (key.isConnectable()){ connect(key); }else if(key.isReadable()){ read(key); } } } } /* 连接 */ public void connect(SelectionKey key) throws IOException { SocketChannel channel=(SocketChannel)key.channel(); //如果正在连接,则连接完成 if(channel.isConnectionPending()){ channel.finishConnect(); } channel.configureBlocking(false); channel.write(ByteBuffer.wrap(new String("HELLO" ).getBytes())); channel.register(this.selector,SelectionKey.OP_READ); } public void read(SelectionKey key) throws IOException { SocketChannel channel=(SocketChannel)key.channel(); //读取缓冲区 ByteBuffer bb=ByteBuffer.allocate(1000); channel.read(bb); byte[] data=bb.array(); String msg=new String(data).trim(); System.out.println("客户端收到信息:"+msg); channel.close(); key.selector().close(); } public static void main(String[] args) throws IOException { NioClient nioClient=new NioClient(); nioClient.init("127.0.0.1",65500); nioClient.working(); }} 转载地址：http://hjuta.baihongyu.com/