golang几种文件读取方式的效率问题

package main 
 
import( 
 "fmt" 
 "os" 
 "flag" 
 "io" 
 "io/ioutil" 
 "bufio" 
 "time" 
) 
 
func read1(path 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])) 
 } 
} 
 
func read2(path 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])) 
 } 
} 
 
func read3(path string){ 
 fi,err := os.Open(path) 
 if err != nil{panic(err)} 
 defer fi.Close() 
 _,err = ioutil.ReadAll(fi) 
 // fmt.Println(string(fd)) 
} 
 
func main(){ 
 
 flag.Parse() 
 file := flag.Arg(0) 
 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)) 
} 

正确结论是
bufio > ioutil > file.Read

本文来自:简书

感谢作者:哆啦在这A梦在哪

查看原文:golang几种文件读取方式的效率问题

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