关于http:HTTP中通过get方法下载文件

http下载文件的实质就是在响应体中拿到响应数据并写入到文件的操作，第二种形式是实现了一个实时显示下载进度的性能

package mainimport (   "fmt"   "io"   "net/http"   "os")func downloadFile(url, fileName string) {   resp, err := http.Get(url)   if err != nil {      panic(err)   }   defer func() {_ = resp.Body.Close()}()   file, err := os.Create(fileName)   if err != nil {      panic(err)   }   defer file.Close()   n, err := io.Copy(file, resp.Body)   fmt.Println(n, err)}type Reader struct {   io.Reader   Total int64   Currnet int64}func (r *Reader) Read(p []byte) (n int, err error) {   n, err = r.Reader.Read(p)   r.Currnet += int64(n)   fmt.Printf("\r %.2f%%", float64(r.Currnet * 10000 / r.Total) / 100)   return}func DownloadFileProgress(url, fileName string){   resp, err := http.Get(url)   if err != nil {      panic(err)   }   defer func() {_ = resp.Body.Close()}()   file, err := os.Create(fileName)   if err != nil {      panic(err)   }   defer file.Close()   reader := &Reader{      Reader:  resp.Body,      Total:   resp.ContentLength,   }   io.Copy(file, reader)}func main(){   //下载文件url   url := "https://i1.hdslb.com/bfs/face/0d2f52b9e1dae83b2cd710b38ee911533db32774.jpg"   //下载后保留的文件名   fileName := "example.png"   //downloadFile(url, fileName)   DownloadFileProgress(url, fileName)}