Netty权威指南-NIO实现TimeClient客户端源代码

package com.jianweigang.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.util.Iterator;import java.util.Set;public class TimeClient {    private static int DEFAULT_PORT = 8080;    public static void main(String[] args) throws IOException {        int port = 8080;        if(args != null && args.length > 0 ) {            try {                port = Integer.valueOf(args[0]);            }catch(NumberFormatException e){                //如果没有传，那我们就使用默认的端口                port = DEFAULT_PORT;            }        }        //单独启动一个线程        new Thread(new TimeClientHandle("127.0.0.1", port), "TimeClient-001").start();    }}class TimeClientHandle implements Runnable{    private String host;    private int port;    private Selector selector;    private SocketChannel socketChannel;    private volatile boolean stop;    public TimeClientHandle(String host, int port) {        this.host = host == null ? "127.0.0.1" : host;        this.port = port;        try {            selector = Selector.open();            socketChannel = SocketChannel.open();            socketChannel.configureBlocking(false);//          socketChannel.register(selector, SelectionKey.OP_READ);        } catch (IOException e) {            e.printStackTrace();            System.exit(1);        }        }    public void run() {        // TODO Auto-generated method stub        try {            doConnect();         } catch (IOException e) {            e.printStackTrace();            System.exit(1);         }        while(!stop) {            try {                selector.select(1000);                Set<SelectionKey> selectedKeys = selector.selectedKeys();                Iterator<SelectionKey> it = selectedKeys.iterator();                SelectionKey key = null;                while(it.hasNext()) {                    key = it.next();                    it.remove();                    try {                        handleInput(key);                    }catch(Exception e) {                        if (key != null) {                            key.cancel();                           if (key.channel() != null)                           key.channel().close();                                        }                    }                }            }catch(Exception e){            }        }        // 多路复用器关闭后，所有注册在上面的Channel和Pipe等资源都会被自动去注册并关闭，所以不需要重复释放资源        if (selector != null)            try {                selector.close();            } catch (IOException e) {                e.printStackTrace();           }    }    private void handleInput(SelectionKey key) throws IOException {        if (key.isValid()) {            // 判断是否连接成功            SocketChannel sc = (SocketChannel) key.channel();            if (key.isConnectable()) {                if (sc.finishConnect()) {                    sc.register(selector, SelectionKey.OP_READ);                    doWrite(sc);           } else               System.exit(1);// 连接失败，进程退出           }           if (key.isReadable()) {               ByteBuffer readBuffer = ByteBuffer.allocate(1024);               int readBytes = sc.read(readBuffer);           if (readBytes > 0) {               readBuffer.flip();               byte[] bytes = new byte[readBuffer.remaining()];               readBuffer.get(bytes);               String body = new String(bytes, "UTF-8");               System.out.println("Now is : " + body);               this.stop = true;           } else if (readBytes < 0) {               // 对端链路关闭               key.cancel();               sc.close();           } else               ; // 读到0字节，忽略           }       }   }   private void doConnect() throws IOException {   // 如果直接连接成功，则注册到多路复用器上，发送请求消息，读应答   if (socketChannel.connect(new InetSocketAddress(host, port))) {       socketChannel.register(selector, SelectionKey.OP_READ);       doWrite(socketChannel);   } else       socketChannel.register(selector, SelectionKey.OP_CONNECT);   }   private void doWrite(SocketChannel sc) throws IOException {       byte[] req = "QUERY TIME ORDER".getBytes();       ByteBuffer writeBuffer = ByteBuffer.allocate(req.length);       writeBuffer.put(req);       writeBuffer.flip();       sc.write(writeBuffer);       if (!writeBuffer.hasRemaining())           System.out.println("Send order 2 server succeed.");       }}