mkdir gomodtest

cd gomodtest

go mod init gomodtest

package main

import "github.com/astaxie/beego"

func main() {

    beego.Run()

}

go run server.go

自动查找依赖并且下载依赖的包到$GOPATH/pkg/mod/github.com/astaxie

go run server.go

go: finding github.com/astaxie/beego v1.12.0

go: downloading github.com/astaxie/beego v1.12.0

go: extracting github.com/astaxie/beego v1.12.0

go: downloading golang.org/x/crypto v0.0.0--eb0de9b17e85

go: downloading gopkg.in/yaml.v2 v2.2.1

go: finding github.com/shiena/ansicolor latest

go: extracting gopkg.in/yaml.v2 v2.2.1

go: downloading github.com/shiena/ansicolor v0.0.0--a422bbe96644

go: extracting golang.org/x/crypto v0.0.0--eb0de9b17e85

go: extracting github.com/shiena/ansicolor v0.0.0--a422bbe96644

go: finding gopkg.in/yaml.v2 v2.2.1

go: finding golang.org/x/crypto v0.0.0--eb0de9b17e85

module gomodtest

go 1.13

require (

    github.com/astaxie/beego v1.12.0 // indirect

    github.com/shiena/ansicolor v0.0.0--a422bbe96644 // indirect

)