读文件

  1. package main
  3. import (
  4.     "bufio"
  5.     "fmt"
  6.     "io"
  7.     "io/ioutil"
  8.     "os"
  9. )
  11. func customRead() {
  12.     fileContent, err := os.Open("./shiwo.txt")
  13.     if err != nil {
  14.         fmt.Println("open file error", err)
  15.     }
  16.     defer fileContent.Close()
  17.     var tmp [128]byte
  18.     n, err := fileContent.Read(tmp[:])
  19.     fmt.Println(string(tmp[:n]))
  20. }
  22. func BufioRead() {
  23.     fileContent, err := os.Open("./shiwo.txt")
  24.     if err != nil {
  25.         fmt.Println("open file error", err)
  26.     }
  27.     defer fileContent.Close()
  28.     render := bufio.NewReader(fileContent)
  30.     for {
  31.         //问题：当读到最后时如果最后不存在换行符会导致最后一行无法读取
  32.         line, err := render.ReadString('\n')
  33.         if err == io.EOF {
  34.             return
  35.         }
  36.         if err != nil {
  37.             fmt.Println("render error ", err)
  38.             return
  39.         }
  41.         fmt.Println(line)
  43.     }
  44. }
  46. func IoutilRead() {
  47.     ret, err := ioutil.ReadFile("./shiwo.txt")
  48.     if err != nil {
  49.         fmt.Println("read file error", err)
  50.     }
  51.     fmt.Println(string(ret))
  52. }
  53. func main() {
  54.     customRead()
  55. }

写文件

  1. package main
  3. import (
  4.     "fmt"
  5.     "io/ioutil"
  6.     "os"
  7. )
  9. func IoutilWrite() {
  10.     err := ioutil.WriteFile("./yy.txt", []byte("niwo"), 0664)
  11.     if err != nil {
  12.         fmt.Println("writer file failed", err)
  13.     }
  14. }
  16. func main() {
  17.     //O_RDONLY int = syscall.O_RDONLY // open the file read-only.
  18.     //O_WRONLY int = syscall.O_WRONLY // open the file write-only.
  19.     //O_RDWR   int = syscall.O_RDWR   // open the file read-write.
  20.     //// The remaining values may be or'ed in to control behavior.
  21.     //O_APPEND int = syscall.O_APPEND // append data to the file when writing.
  22.     //O_CREATE int = syscall.O_CREAT  // create a new file if none exists.
  23.     //O_EXCL   int = syscall.O_EXCL   // used with O_CREATE, file must not exist.
  24.     //O_SYNC   int = syscall.O_SYNC   // open for synchronous I/O.
  25.     //O_TRUNC  int = syscall.O_TRUNC // truncate regular writable file when opened.
  26.     //参数说明，OpenFile（文件名，操作模式，文件权限），文件权限只在linux下生效
  27.     file, err := os.OpenFile("./zz.txt", os.O_CREATE|os.O_APPEND, 0644)
  28.     if err != nil {
  29.         fmt.Println("open file failed", err)
  30.     }
  31.     file.WriteString("hahaha")
  32.     file.Close()
  33. }