Go文件上传下载

Go自带很多包，本例使用io包和net包相应的API简单实现基于http的文件上传下载(仅为demo)

定义文件存储文件

//假设文件上传为本地的服务器，上传的基础路径const BaseUploadPath = "/var/file"

main函数中监听http服务

func main() {	http.HandleFunc("/upload", handleUpload)	http.HandleFunc("/download", handleDownload)	err := http.ListenAndServe(":3000", nil)	if err != nil  {		log.Fatal("Server run fail")	}}

文件上传处理器

func handleUpload (w http.ResponseWriter, request *http.Request)  {	//文件上传只允许POST方法	if request.Method != http.MethodPost {		w.WriteHeader(http.StatusMethodNotAllowed)		_, _ = w.Write([]byte("Method not allowed"))		return	}	//从表单中读取文件	file, fileHeader, err := request.FormFile("file")	if err != nil {		_, _ = io.WriteString(w, "Read file error")		return	}	//defer 结束时关闭文件	defer file.Close()	log.Println("filename: " + fileHeader.Filename)	//创建文件	newFile, err := os.Create(BaseUploadPath + "/" + fileHeader.Filename)	if err != nil {		_, _ = io.WriteString(w, "Create file error")		return	}	//defer 结束时关闭文件	defer newFile.Close()	//将文件写到本地	_, err = io.Copy(newFile, file)	if err != nil {		_, _ = io.WriteString(w, "Write file error")		return	}	_,_ = io.WriteString(w, "Upload success")}

文件下载处理器

func handleDownload (w http.ResponseWriter, request *http.Request) {	//文件上传只允许GET方法	if request.Method != http.MethodGet {		w.WriteHeader(http.StatusMethodNotAllowed)		_, _ = w.Write([]byte("Method not allowed"))		return	}	//文件名	filename := request.FormValue("filename")	if filename == "" {		w.WriteHeader(http.StatusBadRequest)		_, _ = io.WriteString(w, "Bad request")		return	}	log.Println("filename: " + filename)	//打开文件	file, err := os.Open(BaseUploadPath + "/" + filename)	if err != nil {		w.WriteHeader(http.StatusBadRequest)		_, _ = io.WriteString(w, "Bad request")		return	}	//结束后关闭文件	defer file.Close()	//设置响应的header头	w.Header().Add("Content-type", "application/octet-stream")	w.Header().Add("content-disposition", "attachment; filename=/""+filename+"/"")	//将文件写至responseBody	_, err = io.Copy(w, file)	if err != nil {		w.WriteHeader(http.StatusBadRequest)		_, _ = io.WriteString(w, "Bad request")		return	}}

参考资料：golang.org/pkg/