1 package main
2
3 import (
4 "fmt"
5 "io"
6 "io/ioutil"
7 "os"
8 )
9
10 // 该函数：用于通过io操作实现文件的拷贝，返回值是拷贝的总数量(字节),错误
11 func CopyFile1(srcFile, destFile string) (int, error) {
12 file1, err := os.Open(srcFile)
13 if err != nil {
14 return 0, err
15 }
16 file2, err := os.OpenFile(destFile, os.O_WRONLY|os.O_CREATE, os.ModePerm)
17 if err != nil {
18 return 0, err
19 }
20 defer file1.Close()
21 defer file2.Close()
22
23 //读写
24 bs := make([]byte, 1024, 1024)
25 n := -1 //读取的数据量
26 total := 0
27 for {
28 n, err = file1.Read(bs)
29 if err == io.EOF || n == 0 {
30 fmt.Println("拷贝完毕。。")
31 break
32 } else if err != nil {
33 fmt.Println("报错了。。")
34 return total, err
35 }
36 total += n
37 file2.Write(bs[:n])
38 }
39 return total, nil
40 }
41
42 func CopyFile2(srcFile, destFile string) (int64, error) {
43 file1, err := os.Open(srcFile)
44 if err != nil {
45 return 0, err
46 }
47 file2, err := os.OpenFile(destFile, os.O_WRONLY|os.O_CREATE, os.ModePerm)
48 if err != nil {
49 return 0, err
50 }
51 defer file1.Close()
52 defer file2.Close()
53 return io.Copy(file2, file1)
54 }
55
56 func CopyFile3(srcFile, destFile string) (int, error) {
57 bs, err := ioutil.ReadFile(srcFile)
58 if err != nil {
59 return 0, err
60 }
61 err = ioutil.WriteFile(destFile, bs, 0777)
62 if err != nil {
63 return 0, err
64 }
65 return len(bs), nil
66 }
67
68 func main() {
69 /*
70 拷贝文件：
71 */
72
73 srcFile := "D:\\Go\\web2\\aa.txt"
74 destFile := "bb.txt"
75 // 覆盖 destFile 内容 size = srcFile 的部分
76 // total, err := CopyFile1(srcFile, destFile)
77 // 覆盖 destFile 内容 size = srcFile 的部分
78 // total, err := CopyFile2(srcFile, destFile)
79 // 完全重写
80 total, err := CopyFile3(srcFile, destFile)
81 fmt.Println(total, err)
82 }
