bufio.NewWriter、Writer.WriteString、Writer.Flush

耐心和持久胜过激烈和狂热。

哈喽大家好，我是陈明勇，今天分享的知识是 Go 文件的写入操作。如果本文对你有帮助，不妨点个赞，如果你是 Go 语言初学者，不妨点个关注，一起成长一起进步，如果本文有错误的地方，欢迎指出！

前言

Goosbufio

File.Write、File.WriteString、File.WriteAt

File.Write(b []byte) (n int, err error)bnerrFile.WriteString(s string) (n int, err error)snerrFile.WriteAt(b []byte, off int64) (n int, err error)offboffnerr

文件写入操作

import (
	"fmt"
	"os"
)

func main() {
	file, err := os.OpenFile("test.txt", os.O_CREATE, 0)
	if err != nil {
		fmt.Println(err)
		return
	}
	defer file.Close()
	count, err := file.Write([]byte{'H', 'e', 'l', 'l', 'o', ' ', 'W', 'o', 'r', 'l', 'd', '\n'})
	if err != nil {
		return
	}
	fmt.Printf("写入了 %d 字节\n", count)
	count, err = file.WriteString("Hello Golang")
	if err != nil {
		return
	}
	fmt.Printf("写入了长度为 %d 的字符串\n", count)
	count, err = file.WriteAt([]byte{'x', 'x', 'x', 'x', 'x', 'x', 'x', 'x', 'x', 'x', 'x'}, 0)
	if err != nil {
		return
	}
	fmt.Printf("写入了 %d 字节\n", count)
}

Hello World
Hello Golang

xxxxxxxxxxx
Hello Golang

File.Seek

File.Seek(offset int64, whence int)offsetoffsetwhence012

应用

import (
	"fmt"
	"os"
)

func main() {
	file, err := os.OpenFile("test.txt", os.O_CREATE, 0)
	if err != nil {
		fmt.Println(err)
		return
	}
	defer file.Close()
	_, err = file.WriteString("G0lang")
	if err != nil {
		return
	}
	_, err = file.Seek(1, 0)
	if err != nil {
		fmt.Println(err)
		return
	}
	_, err = file.Write([]byte{'o'})
	if err != nil {
		fmt.Println(err)
		return
	}
}

test.txtos.O_CREATEWriteStringG0lang0oSeeko0o0

bufio.NewWriter、Writer.WriteString、Writer.Flush

bufioWriter4096

NewWriter(w io.Writer) *Writer4096WriterwWriterFile*WriterWriterWriter.WriteString(s string) (int, error)sWriter.Flush() error

文件写入操作

import (
	"bufio"
	"fmt"
	"os"
)

func main() {
	file, err := os.OpenFile("test.txt", os.O_CREATE, 0)
	if err != nil {
		fmt.Println(err)
		return
	}
	defer file.Close()
	writer := bufio.NewWriter(file)
	_, err = writer.WriteString("Hello World\n")
	if err != nil {
		fmt.Println(err)
		return
	}
	_, err = writer.WriteString("Hello Golang\n")
	if err != nil {
		fmt.Println(err)
		return
	}
	_, err = writer.WriteString("Hello Gopher\n")
	if err != nil {
		fmt.Println(err)
		return
	}
	writer.Flush()
}

test.txtos.O_CREATENewWriterWriterwriterwriterWriteStringFlush

小结

File.WriteFile.WriteStringFile.WriteAtFile.Seekbufio.NewWriterWriter.WriteStringWriter.Flush