Golang微服务开发可以应用于哪些实际应用案例？

package main

import (
    "log"
    "net/http"
    "github.com/gorilla/websocket"
)

var clients = make(map[*websocket.Conn]bool) // 连接池，用于管理客户端连接
var broadcast = make(chan Message) // 广播消息通道

type Message struct {
    Username string `json:"username"`
    Content  string `json:"content"`
}

func main() {
    upgrader := websocket.Upgrader{} // 创建一个WebSocket升级器

    http.HandleFunc("/ws", func(w http.ResponseWriter, r *http.Request) {
        conn, err := upgrader.Upgrade(w, r, nil) // 升级HTTP连接为WebSocket连接
        if err != nil {
            log.Println(err)
            return
        }

        clients[conn] = true // 将新连接添加到连接池中

        for {
            var msg Message
            err := conn.ReadJSON(&msg) // 读取客户端发送的JSON数据
            if err != nil {
                log.Println(err)
                delete(clients, conn) // 如果读取失败，说明客户端已经断开连接，将其从连接池中删除
                break
            }

            broadcast <- msg // 将消息发送到广播通道
        }
    })

    go handleMessages()

    log.Fatal(http.ListenAndServe(":8080", nil)) // 启动HTTP服务器
}

func handleMessages() {
    for {
        msg := <-broadcast // 从广播通道中接收消息

        // 向所有连接的客户端发送消息
        for client := range clients {
            err := client.WriteJSON(msg)
            if err != nil {
                log.Println(err)
                client.Close()
                delete(clients, client) // 如果发送失败，说明客户端已经断开连接，将其从连接池中删除
            }
        }
    }
}

package main

import (
    "log"
    "net/http"
    "encoding/json"
)

type User struct {
    ID       int    `json:"id"`
    Username string `json:"username"`
    Email    string `json:"email"`
}

func main() {
    http.HandleFunc("/users", func(w http.ResponseWriter, r *http.Request) {
        switch r.Method {
        case http.MethodGet:
            users := []User{
                {ID: 1, Username: "user1", Email: "user1@example.com"},
                {ID: 2, Username: "user2", Email: "user2@example.com"},
                {ID: 3, Username: "user3", Email: "user3@example.com"},
            }

            w.Header().Set("Content-Type", "application/json")
            err := json.NewEncoder(w).Encode(users)
            if err != nil {
                log.Println(err)
                http.Error(w, http.StatusText(http.StatusInternalServerError), http.StatusInternalServerError)
                return
            }
        default:
            http.Error(w, http.StatusText(http.StatusMethodNotAllowed), http.StatusMethodNotAllowed)
            return
        }
    })

    log.Fatal(http.ListenAndServe(":8080", nil))
}

package main

import (
    "fmt"
    "sync"
)

var wg sync.WaitGroup // 等待组，用于等待所有任务结束

func main() {
    numbers := []int{1, 2, 3, 4, 5}

    wg.Add(len(numbers)) // 设置等待组的计数值

    for _, n := range numbers {
        go func(num int) {
            defer wg.Done() // 任务结束时减少等待组的计数值

            result := fibonacci(num)
            fmt.Printf("Fibonacci(%d) = %d
", num, result)
        }(n)
    }

    wg.Wait() // 等待所有任务结束
}

func fibonacci(n int) int {
    if n <= 1 {
        return n
    }

    return fibonacci(n-1) + fibonacci(n-2)
}