求助！！Mac 下go get github.com/astaxie/beego “提示无法识别导入路径”

package bytes: unrecognized import path "bytes" (import path does not begin with hostname) package crypto/tls: unrecognized import path "crypto/tls" (import path does not begin with hostname) package crypto/x509: unrecognized import path "crypto/x509" (import path does not begin with hostname) package encoding/json: unrecognized import path "encoding/json" (import path does not begin with hostname) package errors: unrecognized import path "errors" (import path does not begin with hostname) package fmt: unrecognized import path "fmt" (import path does not begin with hostname) package bufio: unrecognized import path "bufio" (import path does not begin with hostname) package io: unrecognized import path "io" (import path does not begin with hostname) package io/ioutil: unrecognized import path "io/ioutil" (import path does not begin with hostname) package os: unrecognized import path "os" (import path does not begin with hostname) package os/user: unrecognized import path "os/user" (import path does not begin with hostname) package path/filepath: unrecognized import path "path/filepath" (import path does not begin with hostname) package reflect: unrecognized import path "reflect" (import path does not begin with hostname)