go env
go env -w GO111MODULE=on
go env -w GOPROXY=https://goproxy.cn,direct 
go get golang.org/x/tools/cmd/godoc

GOPATH="/Users/dugang/go"
/Users/dugang/go/bin/godoc

/Users/dugang/go/bin/godoc -http :8000
 
http://127.0.0.1:8000/pkg/


https://golang.google.cn/pkg/


ide执行main.go报错cannot find main module; see ‘go help modules’
建议关闭module模式 go env -w GO111MODULE=