浅谈GoLang几种读文件方式的比较

package main  import(   "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))  } 

Cost time 105.006ms Cost time 68.0039ms Cost time 31.0018ms 

Cost time 390.0223ms Cost time 194.0111ms Cost time 83.0048ms 

Cost time 40.8043338s Cost time 1m5.0407201s Cost time 8.8155043s