详解Golang开启http服务的三种方式

//v1
func main() {
  http.HandleFunc("/", func(w http.ResponseWriter, r *http.Request) {
     w.Write([]byte("httpserver v1"))
    })
    http.HandleFunc("/bye", sayBye)
    log.Println("Starting v1 server ...")
    log.Fatal(http.ListenAndServe(":1210", nil))
 }

func sayBye(w http.ResponseWriter, r *http.Request) {
   w.Write([]byte("bye bye ,this is v1 httpServer"))
}

// v2
func main() {
  mux := http.NewServeMux()
  mux.Handle("/", &myHandler{})
  mux.HandleFunc("/bye", sayBye)

  log.Println("Starting v2 httpserver")
  log.Fatal(http.ListenAndServe(":1210", mux))
}
type myHandler struct{}

func (*myHandler) ServeHTTP(w http.ResponseWriter, r *http.Request) {
   w.Write([]byte("this is version 2"))
}
func sayBye(w http.ResponseWriter, r *http.Request) {
   w.Write([]byte("bye bye ,this is v2 httpServer"))
}

// v3
func main() {
  mux := http.NewServeMux()
  mux.Handle("/", &myHandler{})
  mux.HandleFunc("/bye", sayBye)

  server := &http.Server{
    Addr:     ":1210",
    WriteTimeout: time.Second * 3,      //设置3秒的写超时
    Handler:   mux,
  }
  log.Println("Starting v3 httpserver")
  log.Fatal(server.ListenAndServe())
}

type myHandler struct{}

func (*myHandler) ServeHTTP(w http.ResponseWriter, r *http.Request) {
  w.Write([]byte("this is version 3"))
}

func sayBye(w http.ResponseWriter, r *http.Request) {
    // 睡眠4秒 上面配置了3秒写超时，所以访问 “/bye“路由会出现没有响应的现象
  time.Sleep(4 * time.Second)       
  w.Write([]byte("bye bye ,this is v3 httpServer"))
}

// 主动关闭服务器
var server *http.Server
func main() {
  
 // 一个通知退出的chan
quit := make(chan os.Signal)
signal.Notify(quit, os.Interrupt)

mux := http.NewServeMux()
mux.Handle("/", &myHandler{})
mux.HandleFunc("/bye", sayBye)

server = &http.Server{
  Addr:     ":1210",
  WriteTimeout: time.Second * 4,
  Handler:   mux,
}

go func() {
  // 接收退出信号
  <-quit
  if err := server.Close(); err != nil {
    log.Fatal("Close server:", err)
  }
}()

log.Println("Starting v3 httpserver")
err := server.ListenAndServe()
if err != nil {
  // 正常退出
  if err == http.ErrServerClosed {
    log.Fatal("Server closed under request")
  } else {
    log.Fatal("Server closed unexpected", err)
  }
}
 log.Fatal("Server exited")

}

type myHandler struct{}

func (*myHandler) ServeHTTP(w http.ResponseWriter, r *http.Request) {
 w.Write([]byte("this is version 3"))
}

 // 关闭http
func sayBye(w http.ResponseWriter, r *http.Request) {
   w.Write([]byte("bye bye ,shutdown the server"))   // 没有输出
   err := server.Shutdown(nil)
   if err != nil {
    log.([]byte("shutdown the server err"))
   }
 }