标签：func byte fat pac scan world 文件写入 st3 written
一、文件读取
1. 将整个文件读取到内存中
package main
import (
"flag"
"fmt"
"io/ioutil"
)
func main() {
//从命令行标记参数中获取文件路径
fptr := flag.String("fpath", "test.txt", "the file path to read from")
flag.Parse()
data, err := ioutil.ReadFile(*fptr)
if err != nil {
fmt.Println("File reading error: ", err)
}
fmt.Println(string(data))
}
2. 分块读取文件
package main
import (
"bufio"
"flag"
"fmt"
"io"
"log"
"os"
)
func main() {
fptr := flag.String("fpath", "test.txt", "the file path to read from")
flag.Parse()
f, err := os.Open(*fptr)
if err != nil {
log.Fatal(err)
}
defer func() {
if err := f.Close(); err != nil {
log.Fatal(err)
}
}()
r := bufio.NewReader(f)
b := make([]byte, 10)
for {
_, err := r.Read(b)
if err != nil {
if err == io.EOF {
break
}
log.Fatal(err)
}
fmt.Println(string(b))
}
}
3. 逐行读取文件
package main
import (
"bufio"
"flag"
"fmt"
"log"
"os"
)
func main() {
fptr := flag.String("fpath", "test.txt", "the file path to read from")
flag.Parse()
f, err := os.Open(*fptr)
if err != nil {
log.Fatal(err)
}
defer func() {
if err = f.Close(); err != nil {
log.Fatal(err)
}
}()
s := bufio.NewScanner(f)
for s.Scan() {
fmt.Println(s.Text())
}
err = s.Err()
if err != nil {
log.Fatal(err)
}
}
二、文件写入
1. 将字符串写入文件
package main
import (
"fmt"
"log"
"os"
)
func main() {
f, err := os.Create("test2.txt")
if err != nil {
log.Fatal(err)
}
defer func() {
if err = f.Close(); err != nil {
log.Fatal(err)
}
}()
l, err := f.WriteString("Hello world")
if err != nil {
log.Fatal(err)
}
fmt.Println(l, " bytes written successfully!")
}
2. 将字节写入文件
package main
import (
"fmt"
"log"
"os"
)
func main() {
f, err := os.Create("test2.txt")
if err != nil {
log.Fatal(err)
}
defer func() {
if err = f.Close(); err != nil {
log.Fatal(err)
}
}()
d := []byte{104, 101, 108, 108, 111, 32, 119, 111, 114, 108, 100}
l, err := f.Write(d)
if err != nil {
log.Fatal(err)
}
fmt.Println(l, " bytes written successfully!")
}
3. 追加到文件
package main
import (
"fmt"
"log"
"os"
)
func main() {
f, err := os.OpenFile("test3.txt", os.O_APPEND|os.O_WRONLY, 0644)
if err != nil {
log.Fatal(err)
}
defer func() {
if err = f.Close(); err != nil {
log.Fatal(err)
}
}()
_, err = fmt.Fprintln(f, "Hello, my name is jet.")
if err != nil {
log.Fatal(err)
}
}
标签：func byte fat pac scan world 文件写入 st3 written
原文地址：https://www.cnblogs.com/wujuntian/p/11612987.html
