Java基于NIO实现群聊系统

本文实例为大家分享了java基于nio实现群聊系统的具体代码，供大家参考，具体内容如下

实例要求：

1.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）

2.实现多人群聊

3.服务器端：可以监测用户上线，离线，并实现消息转发功能

4.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）

5.目的：进一步理解 nio 非阻塞网络编程机制

6.示意图分析和代码

// 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

以上就是本文的全部内容，希望对大家的学习有所帮助，也希望大家多多支持。