netty学习十一:NIO客户端服务端通讯demo

来源：互联网发布：大数据分析的案例编辑：程序博客网时间：2024/05/24 01:55

概述

本文展示了如何使用NIO来进行客户端和服务端的通讯.

服务端代码

package nio;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.nio.charset.Charset;import java.util.HashMap;import java.util.Iterator;import java.util.Map;import java.util.Set;import java.util.UUID;public class NioServer {    private static Map<String,SocketChannel> clientMap = new HashMap<>();    public static void main(String[] args) throws IOException {        //创建一个服务端的socket channel,但是还未绑定监听地址        ServerSocketChannel serverSocketChannel = ServerSocketChannel.open();        //非阻塞        serverSocketChannel.configureBlocking(false);        ServerSocket serverSocket = serverSocketChannel.socket();        //通过ServerSocet为ServerSocketChannel指定监听地址        //如果不绑定的话,调用ServerSocketChannel的accept方法会抛出NotYetBoundException        serverSocket.bind(new InetSocketAddress(8899));        Selector selector = Selector.open();        //注册连接建立的事件        serverSocketChannel.register(selector, SelectionKey.OP_ACCEPT);        while (true) {            //一直阻塞,直到有感兴趣的事件发生,select方法才会返回            selector.select();            //注册selector在上的事件可能不止一个,这些事件也可能同时发生,所以这里是SelectionKey Set集合            Set<SelectionKey> selectedKeys = selector.selectedKeys();            for (Iterator<SelectionKey> iterator = selectedKeys.iterator(); iterator.hasNext();) {                SelectionKey selectionKey = (SelectionKey) iterator.next();                final SocketChannel client;                //isAcceptable==true,说明客户端和服务端已经建立好连接了                if(selectionKey.isAcceptable()) {                    ServerSocketChannel server = (ServerSocketChannel)selectionKey.channel();                    client = server.accept();                    client.configureBlocking(false);                    client.register(selector,SelectionKey.OP_READ);                    String key = "【"+UUID.randomUUID()+"】";                    clientMap.put(key, client);                    continue;                }                //isReadable==true,说明可以从SocketChannel中读取数据了                if(selectionKey.isReadable()) {                    client = (SocketChannel)selectionKey.channel();                    ByteBuffer readBuffer = ByteBuffer.allocate(1024);                    //从channel中读取数据                    int count = client.read(readBuffer);                    if(count > 0) {                        readBuffer.flip();                        Charset charset = Charset.forName("utf-8");                        //将bytebuffer转换成字符串                        String receiveMessage = String.valueOf(charset.decode(readBuffer).array());                        System.out.println(client+":"+receiveMessage);                        //找出发送消息的客户端                        String sendKey = "";                        for (String key : clientMap.keySet()) {                            SocketChannel socketChannel = clientMap.get(key);                            if (socketChannel == client) {                                sendKey = key;                                break;                            }                        }                        for (String key : clientMap.keySet()) {                            SocketChannel socketChannel = clientMap.get(key);                            ByteBuffer writeBuffer = ByteBuffer.allocate(1024);                            writeBuffer.put((sendKey + ":" +receiveMessage).getBytes());                            writeBuffer.flip();                            socketChannel.write(writeBuffer);                        }                    }                }            }            //清除事件            selectedKeys.clear();        }    }}

客户端代码

package nio;import java.io.BufferedReader;import java.io.IOException;import java.io.InputStreamReader;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.time.LocalDateTime;import java.util.Set;import java.util.concurrent.ExecutorService;import java.util.concurrent.Executors;public class NioClient {    public static void main(String[] args) throws IOException {        SocketChannel socketChannel = SocketChannel.open();        //非阻塞        socketChannel.configureBlocking(false);        //客户端同样需要selector去监听channel        Selector selector = Selector.open();        socketChannel.register(selector, SelectionKey.OP_CONNECT);        socketChannel.connect(new InetSocketAddress("127.0.0.1", 8899));        while(true) {            selector.select();            Set<SelectionKey> selectedKeys = selector.selectedKeys();            for (SelectionKey selectionKey : selectedKeys) {                //isConnectable=true,说明已经跟服务端建立连接了                if(selectionKey.isConnectable()) {                    SocketChannel client = (SocketChannel)selectionKey.channel();                    if (client.isConnectionPending()) {                        client.finishConnect();                        ByteBuffer writeBuffer = ByteBuffer.allocate(1024);                        writeBuffer.put((LocalDateTime.now() + "连接成功").getBytes());                        writeBuffer.flip();                        client.write(writeBuffer);                        //异步给服务端写信息,避免阻塞主线程                        ExecutorService executorService = Executors.newSingleThreadExecutor(Executors.defaultThreadFactory());                        executorService.submit(new Runnable() {                            @Override                            public void run() {                                while(true) {                                    writeBuffer.clear();                                    InputStreamReader inputStreamReader = new InputStreamReader(System.in);                                    BufferedReader bufferedReader = new BufferedReader(inputStreamReader);                                    try {                                        String sendMessage = bufferedReader.readLine();                                        writeBuffer.put(sendMessage.getBytes());                                        writeBuffer.flip();                                        client.write(writeBuffer);                                    } catch (IOException e) {                                        e.printStackTrace();                                    }                                }                            }                        });                    }                    //一旦客户端和服务端建立连接了,立刻注册读事件                    client.register(selector, SelectionKey.OP_READ);                    continue;                }                if(selectionKey.isReadable()) {                    SocketChannel client = (SocketChannel)selectionKey.channel();                    ByteBuffer readBuffer = ByteBuffer.allocate(1024);                    int count = client.read(readBuffer);                    if (count > 0) {                        String receiveMessage = new String(readBuffer.array(),0,count);                        System.out.println(receiveMessage);                    }                }            }            //清除事件            selectedKeys.clear();        }    }}

csdn code 路径

这个项目的源代码放置在csdn code上,欢迎访问。
netty_study

阅读全文

3 0