194 lines
4.5 KiB
Markdown
194 lines
4.5 KiB
Markdown
# Golang 文件操作
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os.File 封装了所有文件相关的操作，File 是一个结构体，有很多方法。
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## 1.os 包
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### 1.1.创建文件
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```go
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func Create(name string) (file *File, err error)
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func NewFile(fd uintptr, name string) *File
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```
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Create 方法示例如下：
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```go
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f,err := os.Create(fileName)
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defer f.Close()
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if err !=nil {
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fmt.Println(err.Error())
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} else {
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_,err=f.Write([]byte("要写入的文本内容"))
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checkErr(err)
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}
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```
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### 1.2.打开文件
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```go
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func Open(name string) (*File, error)
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func OpenFile(name string, flag int, perm FileMode) (*File, error)
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```
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flag 如下：
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```go
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//打开方式
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const (
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//只读模式
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O_RDONLY int = syscall.O_RDONLY // open the file read-only.
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//只写模式
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O_WRONLY int = syscall.O_WRONLY // open the file write-only.
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//可读可写
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O_RDWR int = syscall.O_RDWR // open the file read-write.
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//追加内容
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O_APPEND int = syscall.O_APPEND // append data to the file when writing.
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//创建文件,如果文件不存在
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O_CREATE int = syscall.O_CREAT // create a new file if none exists.
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//与创建文件一同使用,文件必须存在
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O_EXCL int = syscall.O_EXCL // used with O_CREATE, file must not exist
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//打开一个同步的文件流
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O_SYNC int = syscall.O_SYNC // open for synchronous I/O.
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//如果可能,打开时缩短文件
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O_TRUNC int = syscall.O_TRUNC // if possible, truncate file when opened.
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)
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```
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perm 模式如下：
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```go
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const (
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// The single letters are the abbreviations
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// used by the String method's formatting.
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// 文件夹模式
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ModeDir FileMode = 1 << (32 - 1 - iota) // d: is a directory
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// 追加模式
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ModeAppend // a: append-only
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// 单独使用
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ModeExclusive // l: exclusive use
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// 临时文件
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ModeTemporary // T: temporary file; Plan 9 only
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// 象征性的关联
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ModeSymlink // L: symbolic link
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// 设备文件
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ModeDevice // D: device file
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// 命名管道
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ModeNamedPipe // p: named pipe (FIFO)
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// Unix 主机 socket
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ModeSocket // S: Unix domain socket
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// 设置uid
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ModeSetuid // u: setuid
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// 设置gid
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ModeSetgid // g: setgid
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// UNIX 字符串设备，当设备模式是设置unix
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ModeCharDevice // c: Unix character device, when ModeDevice is set
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// 粘性的
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ModeSticky // t: sticky
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// 非常规文件；对该文件一无所知
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ModeIrregular // ?: non-regular file; nothing else is known about this file
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// bit位遮盖，不变的文件设置为none
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// Mask for the type bits. For regular files, none will be set.
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ModeType = ModeDir | ModeSymlink | ModeNamedPipe | ModeSocket | ModeDevice | ModeCharDevice | ModeIrregular
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// 权限位
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ModePerm FileMode = 0777 // Unix permission bits
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)
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```
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### 1.3.获取文件状态
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```go
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func (f *File) Stat() (fi FileInfo, err error)
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```
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### 1.4.读取文件
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```go
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func (f *File) Read(b []byte) (n int, err error)
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```
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### 1.5.写入文件
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```go
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func (f *File) Write(b []byte) (n int, err error)
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```
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### 1.6.设置读写位置
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```go
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/**
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* @param whence
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* os.SEEK_SET: seek relative to the origin of the file
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* os.SEEK_CUR: seek relative to the current offset
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* os.SEEK_END: seek relative to the end
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*/
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func (f *File) Seek(offset int64, whence int) (ret int64, err error)
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```
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## 2.ioutil 包
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### 2.1.读取
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示例如下：
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```go
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package main
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import(
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"io/ioutil"
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"fmt"
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)
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func main(){
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b, err := ioutil.ReadFile("C:/example.txt")
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if err != nil{
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fmt.Println(err)
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}
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fmt.Println(b)
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fmt.Println(string(b))
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}
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```
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### 2.2.写入
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示例如下：
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```go
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package main
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import(
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"io/ioutil"
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"fmt"
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)
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func main(){
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str := []byte("Hello,Go!")
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err := ioutil.WriteFile("C:/example.txt", str, 0644)
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if err != nil{
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panic(err)
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}else{
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fmt.Println("WriteFile Success!")
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}
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}
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```
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## 3.bufio 包
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### 3.1.读文件
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```go
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func NewReader(rd io.Reader) *Reader
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func (b *Reader) Read(p []byte) (n int, err error)
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func (b *Reader) ReadLine() (line []byte, isPrefix bool, err error)
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```
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### 3.2.写文件
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```go
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func NewWriter(w io.Writer) *Writer
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func (b *Writer) Write(p []byte) (nn int, err error)
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```
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