背景内容：

经历了多个版本，基础内容在前面，可以使用之前的基础环境：

v1：
https://blog.csdn.net/wtt234/article/details/132139454

v2：
https://blog.csdn.net/wtt234/article/details/132144907

v3：
https://blog.csdn.net/wtt234/article/details/132148572

v4：
https://blog.csdn.net/wtt234/article/details/132169338

一、修改内容

二、代码

2.1main.go

package main

func main() {
	server := NewServer("127.0.0.1", 8000)
	server.Start()
}

2.2server.go

package main

import (
	"fmt"
	"io"
	"net"
	"sync"
)

type Server struct {
	Ip   string
	Port int

	//在线用户的列表
	OnlineMap map[string]*User
	mapLock   sync.RWMutex

	//消息广播的channel
	Message chan string
}

//创建一个server的接口
func NewServer(ip string, port int) *Server {
	server := &Server{
		Ip:        ip,
		Port:      port,
		OnlineMap: make(map[string]*User),
		Message:   make(chan string),
	}

	return server
}

//监听Message广播消息channel的goroutine，一旦有消息就发送给全部的在线User
func (this *Server) ListenMessager() {
	for {
		msg := <-this.Message

		//将msg发送给全部的在线User
		this.mapLock.Lock()
		for _, cli := range this.OnlineMap {
			cli.C <- msg
		}
		this.mapLock.Unlock()
	}
}

//广播消息的方法
func (this *Server) BroadCast(user *User, msg string) {
	sendMsg := "[" + user.Addr + "]" + user.Name + ":" + msg

	this.Message <- sendMsg
}

func (this *Server) Handler(conn net.Conn) {
	//...当前链接的业务
	//fmt.Println("链接建立成功")

	user := NewUser(conn, this)

	user.Online()

	//接受客户端发送的消息
	go func() {
		buf := make([]byte, 4096)
		for {
			n, err := conn.Read(buf)
			if n == 0 {
				user.Offline()
				return
			}

			if err != nil && err != io.EOF {
				fmt.Println("Conn Read err:", err)
				return
			}

			//提取用户的消息(去除'\n')
			msg := string(buf[:n-1])

			//用户针对msg进行消息处理
			user.DoMessage(msg)
		}
	}()

	//当前handler阻塞
	select {}
}

//启动服务器的接口
func (this *Server) Start() {
	//socket listen
	listener, err := net.Listen("tcp", fmt.Sprintf("%s:%d", this.Ip, this.Port))
	if err != nil {
		fmt.Println("net.Listen err:", err)
		return
	}
	//close listen socket
	defer listener.Close()

	//启动监听Message的goroutine
	go this.ListenMessager()

	for {
		//accept
		conn, err := listener.Accept()
		if err != nil {
			fmt.Println("listener accept err:", err)
			continue
		}

		//do handler
		go this.Handler(conn)
	}
}

2.3user.go

package main

import "net"

type User struct {
	Name string
	Addr string
	C    chan string
	conn net.Conn

	server *Server
}

//创建一个用户的API
func NewUser(conn net.Conn, server *Server) *User {
	userAddr := conn.RemoteAddr().String()

	user := &User{
		Name: userAddr,
		Addr: userAddr,
		C:    make(chan string),
		conn: conn,

		server: server,
	}

	//启动监听当前user channel消息的goroutine
	go user.ListenMessage()

	return user
}

//用户的上线业务
func (this *User) Online() {

	//用户上线,将用户加入到onlineMap中
	this.server.mapLock.Lock()
	this.server.OnlineMap[this.Name] = this
	this.server.mapLock.Unlock()

	//广播当前用户上线消息
	this.server.BroadCast(this, "已上线")
}

//用户的下线业务
func (this *User) Offline() {

	//用户下线,将用户从onlineMap中删除
	this.server.mapLock.Lock()
	delete(this.server.OnlineMap, this.Name)
	this.server.mapLock.Unlock()

	//广播当前用户上线消息
	this.server.BroadCast(this, "下线")

}

//给当前User对应的客户端发送消息
func (this *User) SendMsg(msg string) {
	this.conn.Write([]byte(msg))
}

//用户处理消息的业务
func (this *User) DoMessage(msg string) {
	if msg == "who" {
		//查询当前在线用户都有哪些

		this.server.mapLock.Lock()
		for _, user := range this.server.OnlineMap {
			onlineMsg := "[" + user.Addr + "]" + user.Name + ":" + "在线...\n"
			this.SendMsg(onlineMsg)
		}
		this.server.mapLock.Unlock()

	} else {
		this.server.BroadCast(this, msg)
	}
}

//监听当前User channel的 方法,一旦有消息，就直接发送给对端客户端
func (this *User) ListenMessage() {
	for {
		msg := <-this.C

		this.conn.Write([]byte(msg + "\n"))
	}
}

三、客户端登录

3.1服务运行

go run main.go server.go user.go 
 

 3.2客户端运行