Java基于NIO如何实现群聊系统

2023-06-21 20:06:56 283人浏览薄情痞子

摘要

这篇文章主要为大家展示了“Java基于NIO如何实现群聊系统”，内容简而易懂，条理清晰，希望能够帮助大家解决疑惑，下面让小编带领大家一起研究并学习一下“Java基于Nio如何实现群聊系统”这篇文章吧。具体内容如下实例要求：编写一个 NIO

这篇文章主要为大家展示了“Java基于NIO如何实现群聊系统”，内容简而易懂，条理清晰，希望能够帮助大家解决疑惑，下面让小编带领大家一起研究并学习一下“Java基于Nio如何实现群聊系统”这篇文章吧。

具体内容如下

实例要求：

编写一个 NIO 群聊系统，实现服务器端和客户端之间的数据简单通讯（非阻塞）

实现多人群聊

服务器端：可以监测用户上线，离线，并实现消息转发功能

客户端：通过 Channel 可以无阻塞发送消息给其它所有用户，同时可以接受其它用户发送的消息（有服务器转发得到）

目的：进一步理解 NIO 非阻塞网络编程机制

示意图分析和代码

Java基于NIO如何实现群聊系统

// 服务端：

package com.atguigu.nio.groupchat;import java.io.IOException;import java.net.InetSocketAddress;import java.nio.ByteBuffer;import java.nio.channels.Channel;import java.nio.channels.SelectionKey;import java.nio.channels.Selector;import java.nio.channels.ServerSocketChannel;import java.nio.channels.SocketChannel;import java.util.Iterator;public class GroupChatServer {    //定义属性    private Selector selector;    private ServerSocketChannel listenChannel;    private static final int PORT = 6667;    //构造器    //初始化工作    public GroupChatServer() {        try {            //得到选择器            selector = Selector.open();            //ServerSocketChannel            listenChannel = ServerSocketChannel.open();            //绑定端口            listenChannel.socket().bind(new InetSocketAddress(PORT));            //设置非阻塞模式            listenChannel.configureBlocking(false);            //将该 listenChannel 注册到 selector            listenChannel.reGISter(selector, SelectionKey.OP_ACCEPT);        } catch (IOException e) {            e.printStackTrace();        }    }    public void listen() {        try {            //循环处理            while (true) {                int count = selector.select();                if (count > 0) { //有事件处理                    // 遍历得到 selectionKey 集合                    Iterator<SelectionKey> iterator = selector.selectedKeys().iterator();                    while (iterator.hasNext()) {                        //取出 selectionkey                        SelectionKey key = iterator.next();                        //监听到 accept                        if (key.isAcceptable()) {                            SocketChannel sc = listenChannel.accept();                            sc.configureBlocking(false);                            //将该 sc 注册到 seletor                            sc.register(selector, SelectionKey.OP_READ);                            //提示                            System.out.println(sc.getRemoteAddress() + " 上线 ");                        }                        if (key.isReadable()) {//通道发送read事件，即通道是可读的状态                            // 处理读(专门写方法..)                            readData(key);                        }                        //当前的 key 删除，防止重复处理                        iterator.remove();                    }                } else {                    System.out.println("等待....");                }            }        } catch (Exception e) {            e.printStackTrace();        } finally {            //发生异常处理....        }    }    //读取客户端消息    public void readData(SelectionKey key) {        SocketChannel channel = null;        try {            //得到 channel            channel = (SocketChannel) key.channel();            //创建 buffer            ByteBuffer buffer = ByteBuffer.allocate(1024);            int count = channel.read(buffer);            //根据 count 的值做处理            if (count > 0) {                //把缓存区的数据转成字符串                String msg = new String(buffer.array());                //输出该消息                System.out.println("fORM客户端:" + msg);                //向其它的客户端转发消息(去掉自己),专门写一个方法来处理                sendInfoToOtherClients(msg, channel);            }        } catch (IOException e) {            try {                System.out.println(channel.getRemoteAddress() + "离线了..");                //取消注册                key.cancel();                //关闭通道                channel.close();            } catch (IOException e2) {                e2.printStackTrace();            }        }    }    //转发消息给其它客户(通道)    private void sendInfoToOtherClients(String msg, SocketChannel self) throws IOException {        System.out.println("服务器转发消息中...");        //遍历所有注册到 selector 上的 SocketChannel,并排除 self        for (SelectionKey key : selector.keys()) {            //通过 key 取出对应的 SocketChannel            Channel targetChannel = key.channel();            //排除自己            if (targetChannel instanceof SocketChannel && targetChannel != self) {                //转型                SocketChannel dest = (SocketChannel) targetChannel;                //将 msg 存储到 buffer                ByteBuffer buffer = ByteBuffer.wrap(msg.getBytes());                //将 buffer 的数据写入通道                dest.write(buffer);            }        }    }    public static void main(String[] args) {        //创建服务器对象        GroupChatServer groupChatServer = new GroupChatServer();        groupChatServer.listen();    }}

// 客户端：

package com.atguigu.nio.groupchat;~~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.Scanner;public class GroupChatClient {    //定义相关的属性    private final String HOST = "127.0.0.1";//服务器的ip    private final int PORT = 6667;//服务器端口    private Selector selector;    private SocketChannel socketChannel;    private String username;    //构造器,完成初始化工作    public GroupChatClient() throws IOException {                selector = Selector.open();        //连接服务器        socketChannel = SocketChannel.open(new InetSocketAddress(HOST, PORT));        //设置非阻塞        socketChannel.configureBlocking(false);        //将 channel 注册到selector        socketChannel.register(selector, SelectionKey.OP_READ);        //得到 username        username = socketChannel.getLocalAddress().toString().substring(1);        System.out.println(username + " is ok...");    }    //向服务器发送消息    public void sendInfo(String info) {        info = username + " 说：" + info;        try {            socketChannel.write(ByteBuffer.wrap(info.getBytes()));        } catch (IOException e) {            e.printStackTrace();        }    }    //读取从服务器端回复的消息    public void readInfo() {        try {            int readChannels = selector.select();            if (readChannels > 0) {//有可以用的通道                Iterator<SelectionKey> iterator = selector.selectedKeys().iterator();                while (iterator.hasNext()) {                    SelectionKey key = iterator.next();                    if (key.isReadable()) {                        //得到相关的通道                        SocketChannel sc = (SocketChannel) key.channel();                        //得到一个 Buffer                        ByteBuffer buffer = ByteBuffer.allocate(1024);                        //读取                        sc.read(buffer);                        //把读到的缓冲区的数据转成字符串                        String msg = new String(buffer.array());                        System.out.println(msg.trim());                    }                }                iterator.remove(); //删除当前的 selectionKey,防止重复操作            } else {                //System.out.println("没有可以用的通道...");            }        } catch (Exception e) {            e.printStackTrace();        }    }    public static void main(String[] args) throws Exception {        //启动我们客户端        GroupChatClient chatClient = new GroupChatClient();        //启动一个线程,每个 3 秒，读取从服务器发送数据        new Thread() {            public void run() {                while (true) {                    chatClient.readInfo();                    try {                        Thread.currentThread().sleep(3000);                    } catch (InterruptedException e) {                        e.printStackTrace();                    }                }            }        }.start();        //发送数据给服务器端        Scanner scanner = new Scanner(System.in);        while (scanner.hasNextLine()) {            String s = scanner.nextLine();            chatClient.sendInfo(s);        }    }}

运行结果

Java基于NIO如何实现群聊系统