How to use gzip package for compression

In the Go language, you can use the gzip package to perform compression and decompression operations. The gzip package provides two functions: gzip.NewReader() and gzip.NewWriter() to create readers and writers. Below we will introduce in detail how to use the gzip package for compression.

1. Compression operation

First, we need to create an output file and use the gzip.NewWriter() function to create a writer. We can then use the write() function to write the data to the gzip file. After writing is completed, call the Close() function to close the gzip file.

The following is a simple compression program that compresses a text file into a gzip format file:

package main
  
import (
    "compress/gzip"
    "os"
)
  
func main() {
    // 创建压缩文件
    output, err := os.Create("test.gz")
    if err != nil {
        panic(err)
    }
    defer output.Close()
  
    // 创建写入器
    writer := gzip.NewWriter(output)
    defer writer.Close()
  
    // 读取数据并压缩
    data := []byte("Hello, Golang!")
    _, err = writer.Write(data)
    if err != nil {
        panic(err)
    }
    writer.Flush()
}

When we run the program, a gzip format named test.gz will be generated. document.

In the above example, we used the writer.Flush() function, which is a method of writing data from the cache to the output stream. It's very important because the gzip package uses caching to improve performance. If we do not call the Flush() function, the data output to the file may be incomplete.

2. Decompression operation

The above describes how to perform the compression operation. Next we will take a look at how to perform the decompression operation.

First, we need to create a gzip file and then create a reader using the gzip.NewReader() function. Next, we can use the read() function to read data from the gzip file. After completion, we call the Close() function to close the gzip file.

The following is a simple decompression program that decompresses a gzip file named test.gz into a text file:

package main
  
import (
    "compress/gzip"
    "io"
    "os"
)
  
func main() {
    // 打开gzip文件并创建读取器
    input, err := os.Open("test.gz")
    if err != nil {
        panic(err)
    }
    defer input.Close()
    reader, err := gzip.NewReader(input)
    defer reader.Close()
  
    // 读取数据并解压缩
    output, err := os.Create("test.txt")
    if err != nil {
        panic(err)
    }
    defer output.Close()
    _, err = io.Copy(output, reader)
    if err != nil {
        panic(err)
    }
}

When we run the program, a name will be generated The file is test.txt.

3. Summary

In the Go language, it is very convenient and simple to use the gzip package for compression and decompression. The gzip package provides the gzip.NewReader() and gzip.NewWriter() functions for creating readers and writers, and the io.Copy() function for reading data from readers and writing to writers. in the vessel.

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