What should I do if golang reads garbled files?

As a development language, golang can be said to be relatively convenient in terms of file reading and writing, but there are still some problems encountered in actual development, such as garbled characters after files are read. This article will introduce the reasons and solutions for reading garbled files in golang.

1. Problem background

When we use golang to read files, sometimes the content after reading will be garbled, as shown in the following figure:

2. Cause of the problem

There are many reasons for garbled characters. The following are some common situations:

2.1. File encoding format does not match

The file encoding format refers to the encoding format of the file content when it is stored, not the extension. When golang reads files, it reads them in UTF-8 encoding format by default. If the read file is not in UTF-8 encoding format, garbled characters will appear.

For example, we can create a txt text file through the cmd command line tool of the Windows system and save it using the "gbk" encoding format, as shown in the following figure:

Then, we use the golang program to read, as shown in the following figure:

It can be found that the content of the read file is garbled. This is due to The default encoding format of golang is UTF-8.

2.2. Endianness is not handled correctly

In golang, when reading files, if the encoding format is UTF-16 (including UTF-16LE and UTF-16BE), you need to Correctly handle endianness. UTF-16LE means that in memory, the low-order bytes are stored in front and the high-order bytes are stored in the back, while UTF-16BE is the opposite.

If we do not handle the byte order correctly when reading UTF-16 files, garbled characters will appear.

2.3. Other encoding format conversion issues

Sometimes, we may need to convert files in other formats (such as CSV, XML, etc.) to the format supported by golang for reading, but during the conversion There may be encoding format conversion problems resulting in garbled characters.

3. Solution

For the above situations, we can adopt the following solutions:

3.1. Confirm the file encoding format and read it

If we already know the encoding format of the file, we need to specify the corresponding encoding format when reading the file.

golang provides a ReadFile method of the ioutil package, which can be used to read files very conveniently. When using this method, you can specify the file encoding format through methods such as bufio.NewReader and ioutil.NopCloser. The code is as follows:

func ReadFileWithCharset(filename string, charset string) ([]byte, error) {
    f, err := os.Open(filename)
    if err != nil {
        return nil, err
    }
    defer f.Close()

    r, err := charset.NewReader(f)
    if err != nil {
        return nil, err
    }
    defer r.Close()

    return ioutil.ReadAll(r)
}

where The charset.NewReader method will generate a new ReadCloser object according to the specified encoding format, and use this object to read the file.

3.2. Use the unicode/utf16 library for byte order conversion

When using the unicode/utf16 library, you need to pay attention to the maximum size in the library The length is 32767 bytes, if the file size exceeds this limit, segmented reading is required.

Code example:

package main

import (
    "fmt"
    "io/ioutil"
    "unicode/utf16"
)

func readUTF16File(filename string) ([]byte, error) {
    data, err := ioutil.ReadFile(filename)
    if err != nil {
        return nil, err
    }

    u := utf16.Decode(data)

    return []byte(string(u)), nil
}

func main() {
    data, _ := readUTF16File("test.txt")
    fmt.Println(string(data))
}

3.3. Use golang.org/x/text library for encoding format conversion

golang.org/ The x/text library provides a very detailed encoding format conversion function that can solve most problems related to encoding formats.

Code example:

package main

import(
    "fmt"
    "io/ioutil"
    "golang.org/x/text/encoding/charmap"
)

func ReadFileWithCharset(filename string, charset string) ([]byte, error) {
    data, err := ioutil.ReadFile(filename)
    if err != nil {
        return nil, err
    }

    charmap := charmap.Windows1252.NewDecoder()

    return charmap.Bytes(data)
}

func main() {
    data,_:=ReadFileWithCharset("test.txt","UTF-8")
    fmt.Println(string(data))
}

4. Summary

The problem of garbled characters is a very common problem in development, and in golang, solutions should be chosen according to the specific situation. If the file encoding format is determined, the corresponding encoding format should be specified during the file reading process; if byte order issues are involved, you need to use the unicode/utf16 library for byte order conversion; for other For encoding format conversion issues, you can use the golang.org/x/text library for conversion. Through the above methods, the problem of reading garbled characters in golang files can be effectively solved and development efficiency improved.

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