go语言实现上传下载功能

以下是一个简单的Go语言实现文件上传和下载的示例代码：

上传文件：

func handleUpload(w http.ResponseWriter, r *http.Request) {
    if r.Method != "POST" {
        http.Error(w, "Method not allowed", http.StatusMethodNotAllowed)
        return
    }

    file, _, err := r.FormFile("file")
    if err != nil {
        http.Error(w, err.Error(), http.StatusBadRequest)
        return
    }
    defer file.Close()

    // 将文件保存到本地
    f, err := os.OpenFile("uploaded_file", os.O_WRONLY|os.O_CREATE, 0666)
    if err != nil {
        http.Error(w, err.Error(), http.StatusInternalServerError)
        return
    }
    defer f.Close()

    io.Copy(f, file)

    w.WriteHeader(http.StatusOK)
}

下载文件：

func handleDownload(w http.ResponseWriter, r *http.Request) {
    if r.Method != "GET" {
        http.Error(w, "Method not allowed", http.StatusMethodNotAllowed)
        return
    }

    f, err := os.Open("uploaded_file")
    if err != nil {
        http.Error(w, err.Error(), http.StatusInternalServerError)
        return
    }
    defer f.Close()

    // 设置响应头，告诉浏览器文件类型和文件名
    w.Header().Set("Content-Type", "application/octet-stream")
    w.Header().Set("Content-Disposition", fmt.Sprintf("attachment; filename=\"%s\"", "uploaded_file"))

    io.Copy(w, f)
}

在main函数中，可以将这两个函数绑定到HTTP路由上：

func main() {
    http.HandleFunc("/upload", handleUpload)
    http.HandleFunc("/download", handleDownload)

    http.ListenAndServe(":8080", nil)
}

现在，访问http://localhost:8080/upload可以上传文件，访问http://localhost:8080/download可以下载刚刚上传的文件。