go语言中，main函数调用其它文件夹下的函数

需求，main.go调用httpServer.go下的Start方法。

结构目录：

main.go中import 需要引用的文件路径

package main

import (
	"fmt"
	// 这里的路径开头为项目go.mod中的module
	"engine_stability_platform/src/app/httpServer"
)
 
func main() {
	
	fmt.Println("main.....")
	httpServer.Start()
}

go.mod
这里要注意，如果不是根目录或者显示的是*.go的，说明go.mod的时候地址不对，把当前go.mod删除，然后进入到项目根目录，按照上述代码为engine_stability_platform，在控制台的终端，进入到该目录下

go mod init 模块名称

即

go mod init engine_stability_platform

然后会生成新的go.mod文件，内容如下所示

module engine_stability_platform

go 1.17

httpServer.go

package httpServer

import (
	. "fmt"
	"html"
	"net/http"
	"time"
)

var count int = 1
// 测试demo
func Task(w http.ResponseWriter, r *http.Request) {
	Printf(" ------ here is Task[%d] ------- \n", count)
	//defer r.Body.Close()
	// 模拟延时
	time.Sleep(time.Second * 2)
 
	Fprintf(w, "Response.No.%d: Your request is %q\n\n", count, html.EscapeString(r.URL.Path))
	count++
	answer := `{"status:":"OK"}`
	w.Write([]byte(answer))
}
 
func Task1(w http.ResponseWriter, r *http.Request) {
	Printf(" ------ here is Task1[%d] ------- \n", count)
	//defer r.Body.Close()
	// 模拟延时
	time.Sleep(time.Second * 2)
 
	Fprintf(w, "Response.No[%d]: Your request is %q\n\n", count, html.EscapeString(r.URL.Path))
	count++
	answer := `{"status:":"OK"}`
	w.Write([]byte(answer))
}
var server *http.Server

func Start() {
	Println("===== This is http server =====")
	mux := http.NewServeMux()
	mux.HandleFunc("/hello/world", Task)
	mux.HandleFunc("/hello/world1", Task1)
	// 启动静态服务
	http.Handle("/static/css/", http.FileServer(http.Dir("dist")))
    http.Handle("/static/js/", http.FileServer(http.Dir("dist")))

	if server != nil {
		// 避免重复start server 端口泄露
		server.Close()
	}
	// 设置服务器
	server := &http.Server{
		Addr: "127.0.0.1:8090",
		Handler: mux,
	}
	// 设置服务器监听端口
	server.ListenAndServe()
}

运行结果：

问题：

# command-line-arguments
./main.go:5:2: imported and not used: "engine_stability_platform/src/app/httpServer" as app
./main.go:13:2: undefined: httpserver
DIDI-C02G51DQQ05G:engine_stability_platform didi$ go run *.go
# command-line-arguments
./main.go:5:2: imported and not used: "engine_stability_platform/src/app/httpServer" as app
./main.go:13:2: undefined: httpserver
DIDI-C02G51DQQ05G:engine_stability_platform didi$ go run main.go
# command-line-arguments
./main.go:5:2: imported and not used: "engine_stability_platform/src/app/httpServer" as app
./main.go:13:2: undefined: httpServer
DIDI-C02G51DQQ05G:engine_stability_platform didi$ go run main.go
main.go:5:2: package engine_stability_platform/src/app/httpServer/httpServer is not in GOROOT (/usr/local/go/src/engine_stability_platform/src/app/httpServer/httpServer)

如果是在运行中出现以下类似问题，说明go.mod的时候地址不对，把当前go.mod删除，然后进入到项目根目录，按照上述代码为engine_stability_platform，在控制台的终端，进入到该目录下

go mod init 模块名称

既

go mod init engine_stability_platform

此时会生成一个新的mod文件，然后该文件的module就是根目录了

更多go mod命令使用，参考：https://blog.youkuaiyun.com/weixin_39689347/article/details/111215800