godemo/v2/main.go 

只有 main.go 

go run main.go
main.go:8:2: cannot find package "github.com/gorilla/mux" in any of:
        /usr/local/go/src/github.com/gorilla/mux (from $GOROOT)
        /Users/dugang/go/src/github.com/gorilla/mux (from $GOPATH)

go env
GO111MODULE="auto"
GOPROXY="https://goproxy.cn"

GOPROXY 推荐设置成 goproxy.cn
export GOPROXY=https://goproxy.cn


go mod init main
go: creating new go.mod: module main
go: to add module requirements and sums:
        go mod tidy

此时 go.mod 内容
module main

go 1.19



自动添加依赖
go mod tidy  
go: finding module for package github.com/gorilla/mux
go: found github.com/gorilla/mux in github.com/gorilla/mux v1.8.0

go.mod 内容
module main

go 1.19

require github.com/gorilla/mux v1.8.0

自动生成 go.sum 


go run main.go
启动后 浏览器测试
http://127.0.0.1:8080 
http://127.0.0.1:8080/todos 
http://127.0.0.1:8080/todos/1



main.go 

package main

import (
	"fmt"
	"log"
	"net/http"

	"github.com/gorilla/mux"
)

func main() {

	router := mux.NewRouter().StrictSlash(true)
	router.HandleFunc("/", Index)
	router.HandleFunc("/todos", TodoIndex)
	router.HandleFunc("/todos/{todoId}", TodoShow)

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

func Index(w http.ResponseWriter, r *http.Request) {
	fmt.Fprint(w, "Welcome!\n")
}

func TodoIndex(w http.ResponseWriter, r *http.Request) {
	fmt.Fprint(w, "Todo Index!\n")
}

func TodoShow(w http.ResponseWriter, r *http.Request) {
	vars := mux.Vars(r)
	todoId := vars["todoId"]
	fmt.Fprintf(w, "Todo show: %s\n", todoId)
}


完整代码 

https://gitee.com/dyyx/hellocode/tree/master/demo/go/rest-json-api/v3