根据维基百科，数据压缩或文件压缩可以理解为在保留原始数据的同时减小特定文件/文件夹/任何数据的大小的过程。较小的文件大小有很多好处，因为它会占用较少的存储区域，为您提供更多空间供其他数据占用，由于文件大小较小，因此文件传输速度更快，并且在文件压缩时可以解锁各种其他特权。压缩文件以“.zip ”、“. rar ”、“. tar.gz ”、“. arj ”和“ .tgz ”等压缩文件扩展名文件夹的形式存储。压缩将文件大小减小到最大压缩大小。如果不能进一步压缩，则大小应保持不变而不是更小。
数据压缩后，我们经常觉得需要撤消它们，以使其易于访问。这个撤销过程称为解压缩。从压缩文件中提取普通文件/文件夹的过程称为解压缩。
但是如何解压缩文件？
有各种软件可以为我们执行此类任务；我知道的一个最好的例子是 WinRAR/WinZip。它们能够压缩和解压缩数据文件。但是我们单独依赖软件多久？他们的大部分功能都是付费的，除了财务方面，我们编码人员是否必须永远依赖外包应用程序来满足我们的需求？或者我们可以挖掘出我们自己的方式来满足我们的要求吗？那么，数据解压缩也可以手动完成。下面将使用 GoLang 讨论一种这样的手动方法。
例子：
案例场景：文件存在于已归档的文件夹中。该程序将所有文件提取到目标目的地。
Go
package main
import (
"archive/zip"
"fmt"
"io"
"log"
"os"
"path/filepath"
"strings"
)
func main() {
// Unzip accepts two arguments:
// First argument represents
// the source directory
// path where archived files are present.
// Second argument represents the
// destination directory path where unzipped
// files will be stored after uncompression.
// Note that destination folder will be created
// inside pwd and then files will be
// extracted into the destination folder.
// Unzip returns 2 values:
// names of files in archived directory & error (if any)
files, err := Unzip("compression-test.zip", "uncompressed files")
// If any error is present then that
// error value will be assigned to err
// In case of no error, err will be equal to nill
// condition check to ensure if any error
// is present we'd print the error message
// and log the error using log.Fatal
if err != nil {
log.Fatal(err)
}
fmt.Println("Unzipped the following files:\n" + strings.Join(files, "\n"))
//end of main function
}
// Unzip will decompress a zip archived file,
// copying all files and folders
// within the zip file (parameter 1)
// to an output directory (parameter 2).
func Unzip(src string, destination string) ([]string, error) {
// a variable that will store any
//file names available in a array of strings
var filenames []string
// OpenReader will open the Zip file
// specified by name and return a ReadCloser
// Readcloser closes the Zip file,
// rendering it unusable for I/O
// It returns two values:
// 1. a pointer value to ReadCloser
// 2. an error message (if any)
r, err := zip.OpenReader(src)
// if there is any error then
// (err!=nill) becomes true
if err != nil {
// and this block will break the loop
// and return filenames gathered so far
// with an err message, and move
// back to the main function
return filenames, err
}
defer r.Close()
// defer makes sure the file is closed
// at the end of the program no matter what.
for _, f := range r.File {
// this loop will run until there are
// files in the source directory & will
// keep storing the filenames and then
// extracts into destination folder until an err arises
// Store "path/filename" for returning and using later on
fpath := filepath.Join(destination, f.Name)
// Checking for any invalid file paths
if !strings.HasPrefix(fpath, filepath.Clean(destination)+string(os.PathSeparator)){
return filenames, fmt.Errorf("%s is an illegal filepath", fpath)
}
// the filename that is accessed is now appended
// into the filenames string array with its path
filenames = append(filenames, fpath)
if f.FileInfo().IsDir() {
// Creating a new Folder
os.MkdirAll(fpath, os.ModePerm)
continue
}
// Creating the files in the target directory
if err = os.MkdirAll(filepath.Dir(fpath), os.ModePerm); err != nil {
return filenames, err
}
// The created file will be stored in
// outFile with permissions to write &/or truncate
outFile, err := os.OpenFile(fpath,
os.O_WRONLY|os.O_CREATE|os.O_TRUNC,
f.Mode())
// again if there is any error this block
// will be executed and process
// will return to main function
if err != nil {
// with filenames gathered so far
// and err message
return filenames, err
}
rc, err := f.Open()
// again if there is any error this block
// will be executed and process
// will return to main function
if err != nil {
// with filenames gathered so far
// and err message back to main function
return filenames, err
}
_, err = io.Copy(outFile, rc)
// Close the file without defer so that
// it closes the outfile before the loop
// moves to the next iteration. this kinda
// saves an iteration of memory & time in
// the worst case scenario.
outFile.Close()
rc.Close()
// again if there is any error this block
// will be executed and process
// will return to main function
if err != nil {
// with filenames gathered so far
// and err message back to main function
return filenames, err
}
}
// Finally after every file has been appended
// into the filenames string[] and all the
// files have been extracted into the
// target directory, we return filenames
// and nil as error value as the process executed
// successfully without any errors*
// *only if it reaches until here.
return filenames, nil
}My pwd path : ../src/myprograms/unzip and zip
Source zip folder : ../src/myprograms/unzip and zip/compression-test.zip
Compression-test.zip contains : Hello world.txt main.go
Destination path : ../src/myprograms/unzip and zip/uncompressed files
Output on my screen:
Unzipped the following files:
uncompressed files\compression-test\Hello world.txt
uncompressed files\compression-test\main.go
Visual Studio Code 上的可视化演示：