ws := new(restful.WebService)
	ws.Path("/download").Consumes(restful.MIME_JSON,restful.MIME_OCTET).
		Produces(restful.MIME_JSON, restful.MIME_OCTET)

MIME_XML   = "application/xml"          // Accept or Content-Type used in Consumes() and/or Produces()
	MIME_JSON  = "application/json"         // Accept or Content-Type used in Consumes() and/or Produces()
	MIME_OCTET = "application/octet-stream" // If Content-Type is not present in request, use the default

ws.Route(ws.GET("/img").To(download.DownLoadRequest).Doc("Add user").
		Returns(http.StatusOK, "下載成功", ""))
	//注冊webservice
	restful.Add(ws)
	log.Fatal(http.ListenAndServe(":8080", nil)) // 啟動監(jiān)聽

func DownLoadRequest(request *restful.Request, response *restful.Response) {
	// 建立客戶端去Get請求一個資源，此處以一張圖片為例子
	client := http.Client{}
	defer client.CloseIdleConnections()
	res, err := client.Get("https://img-home.csdnimg.cn/images/20201124032511.png")
	if err != nil {
		response.WriteError(http.StatusInternalServerError, errors.New("下載失敗"))
	}
	//此處是關鍵
	response.ResponseWriter.Header().Set(restful.HEADER_ContentType, restful.MIME_OCTET)
	response.ResponseWriter.Header().Set("Content-Disposition", "attachment;filename=20201124032511.png")
	// 將客戶端請求的結果序列化出來
	// 不要忘了關閉Body
	defer res.Body.Close()
	b, err := ioutil.ReadAll(res.Body)
	if err != nil {
		response.WriteError(http.StatusInternalServerError, errors.New("下載失敗"))
	}
	_, err = response.ResponseWriter.Write(b)
	if err != nil {
		response.WriteError(http.StatusInternalServerError, errors.New("文件讀取失敗"))
	}
}