golang本地反向代理被拒绝

func main() {
    http.HandleFunc("/a", func(writer http.ResponseWriter, request *http.Request) {
        remote, _ := url.Parse("http://localhost:9000")
        proxy := httputil.NewSingleHostReverseProxy(remote)
        proxy.ServeHTTP(writer, request)
    })

    err := http.ListenAndServe(":8080", nil)
    if err != nil {
        fmt.Println(err)
    }
}

在本地环境的反向代理提示 http: proxy error: dial tcp 127.0.0.1:9000: connect: connection refused 防火墙已经关了 哪位可以告诉下怎么解决