GoLang几种读文件方式的比较
package mainimport(
"fmt"
"os"
"flag"
"io"
"io/ioutil"
"bufio"
"time"
)
func read1(path string)string{
fi,err := os.Open(path)
if err != nil{
panic(err)
}
defer fi.Close()
chunks := make([]byte,1024,1024)
buf := make([]byte,1024)
for{
n,err := fi.Read(buf)
if err != nil && err != io.EOF{panic(err)}
if 0 ==n {break}
chunks=append(chunks,buf[:n]...)
// fmt.Println(string(buf[:n]))
}
return string(chunks)
}
func read2(path string)string{
fi,err := os.Open(path)
if err != nil{panic(err)}
defer fi.Close()
r := bufio.NewReader(fi)
chunks := make([]byte,1024,1024)
buf := make([]byte,1024)
for{
n,err := r.Read(buf)
if err != nil && err != io.EOF{panic(err)}
if 0 ==n {break}
chunks=append(chunks,buf[:n]...)
// fmt.Println(string(buf[:n]))
}
return string(chunks)
}
func read3(path string)string{
fi,err := os.Open(path)
if err != nil{panic(err)}
defer fi.Close()
fd,err := ioutil.ReadAll(fi)
// fmt.Println(string(fd))
return string(fd)
}
func main(){
flag.Parse()
file := flag.Arg(0)
f,err := ioutil.ReadFile(file)
if err != nil{
fmt.Printf("%s\n",err)
panic(err)
}
fmt.Println(string(f))
start := time.Now()
read1(file)
t1 := time.Now()
fmt.Printf("Cost time %v\n",t1.Sub(start))
read2(file)
t2 := time.Now()
fmt.Printf("Cost time %v\n",t2.Sub(t1))
read3(file)
t3 := time.Now()
fmt.Printf("Cost time %v\n",t3.Sub(t2))
}
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