netty学习（6）---NIO服务器端实现

来源：互联网发布：unity3d云雾特效编辑：程序博客网时间：2024/06/16 06:08

NIO服务器创建的步骤：

步骤一：打开ServerSocketChannel，用于监听客户端的连接，它是所有客户端连接的父管道：

serverSocketChannel = ServerSocketChannel.open()

步骤二：绑定监听端口，设置连接为非阻塞模式：

serverSocketChannel.configureBlocking(false);//设置连接为非阻塞模式 serverSocketChannel.socket().bind(new InetSocketAddress(port), 1024)

步骤三：创建Reactor线程，创建多路复用器并启动线程：

selector = Selector.open(); //创建多路复用器Selectornew Thread(new ReactorTask()).start();

步骤四：将ServerSocketChannel注册到Reactor线程的多路复用器Selector上，监听ACCEPT事件：

 serverSocketChannel.register(selector, SelectionKey.OP_ACCEPT);

步骤五：多路复用器在线程run方法的无限循环体内轮询准备就绪的Key

步骤六：多路复用器接收到有新的客户端接入，处理新的接入请求，完成TCP三次握手，建立物理链路：

SocketChannel sc = ssc.accept(); //处理新的请求，完成TCP三次握手，建立物理链路

步骤七：设置客户端链路为非阻塞模式

 sc.configureBlocking(false); //设置客户端链路为非阻塞模式

步骤八：将新接入的客户端连接注册到Reactor线程的多路复用器上，监听读操作，用来读取客户端发送的网络消息：

                //add the new connection to the selector                sc.register(selector, SelectionKey.OP_READ); //将客户端连接注册到多路复用器上，监听读操作，用来监听客户端发送的网络消息

步骤九：异步读取客户端的请求消息到缓冲区：

int readBytes = sc.read(readBuffer);

步骤十：对ByteBuffer消息进行编码，如果有半包消息指针reset，继续读取后续的保温，将解码成功的消息封装成Task，投递到业务线程池中，进行业务逻辑编排.

步骤十一：将POJO对象encode成ByteBuffer，调用SocketChannel的异步write接口，将消息异步发送给客户端:

channel.write(writeBuffer);

下面用NIO实现TimeServer：

TimeServer

package com.panther.dong.netty.nio;/** * Created by panther on 15-8-26. */public class TimeServer {    public static void main(String[] args) {        int port = 12306;        if (args != null && args.length > 0) {            try {                port = Integer.valueOf(args[0]);            } catch (Exception e) {            }        }        MultiplexerTimeServer timeServer = new MultiplexerTimeServer(port);        new Thread(timeServer, "NIO-MultiplexerTimeServer-001").start();    }}

MultiplexerTimeServer:

package com.panther.dong.netty.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.ServerSocketChannel;import java.nio.channels.SocketChannel;import java.util.Date;import java.util.Iterator;import java.util.Set;/** * Created by panther on 15-8-26. */public class MultiplexerTimeServer implements Runnable {    private Selector selector;    private ServerSocketChannel serverSocketChannel;    private volatile boolean stop;    /**     * 初始化多路复用器、绑定监听端口     *     * @param port     */    public MultiplexerTimeServer(int port) {        try {            selector = Selector.open(); //创建多路复用器Selector            serverSocketChannel = ServerSocketChannel.open(); //打开ServerSocketChannel,用于监听客户端的连接            serverSocketChannel.configureBlocking(false);//设置连接为非阻塞模式            serverSocketChannel.socket().bind(new InetSocketAddress(port), 1024);//绑定监听端口，设置连接为非阻塞模式            serverSocketChannel                    .register(selector, SelectionKey.OP_ACCEPT); //将serversocketchannel注册到多路复用器Selector上，监听ACCEPT事件            System.out.println("The time server is start in port : " + port);        } catch (IOException e) {            e.printStackTrace();            System.exit(1);        }    }    public void stop() {        this.stop = true;    }    @Override    public void run() {        //多路复用器无限轮询准备就绪的key        while (!stop) {            try {                selector.select(1000);                Set<SelectionKey> selectionKeys = selector.selectedKeys();                Iterator<SelectionKey> iterator = selectionKeys.iterator();                SelectionKey key = null;                while (iterator.hasNext()) {                    key = iterator.next();                    handleInput(key); //多路复用器处理ACCEPT事件                    iterator.remove();                }            } catch (IOException e) {                e.printStackTrace();            }        }    }    private void handleInput(SelectionKey key) throws IOException {        if (key.isValid()) {            //处理新接入的请求消息            if (key.isAcceptable()) {                //Accept the new Connection                ServerSocketChannel ssc = (ServerSocketChannel) key.channel();                SocketChannel sc = ssc.accept(); //处理新的请求，完成TCP三次握手，建立物理链路                sc.configureBlocking(false); //设置客户端链路为非阻塞模式                //add the new connection to the selector                sc.register(selector, SelectionKey.OP_READ); //将客户端连接注册到多路复用器上，监听读操作，用来监听客户端发送的网络消息            }            if (key.isReadable()) {                //read the data                SocketChannel sc = (SocketChannel) key.channel();                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("the time server receive order : " + body);                    String currentTime = "QUERY TIME ORDER".equalsIgnoreCase(body) ?                            new Date(System.currentTimeMillis()).toString() :                            "BAD ORDER";                    doWrite(sc, currentTime);                } else if (readBytes < 0) {                    key.cancel();                    sc.close();                } else {                    ; //读到0字节，忽略                }            }        }    }    private void doWrite(SocketChannel channel, String response) throws IOException {        if (response != null && response.trim().length() > 0) {            byte[] bytes = response.getBytes();            ByteBuffer writeBuffer = ByteBuffer.allocate(bytes.length);            writeBuffer.put(bytes);            writeBuffer.flip();            channel.write(writeBuffer);        }    }}

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