将JSON [] byte封送为Go中的字符串 [英] Marshaling JSON []byte as strings in Go

问题描述

我有一个结构，其中包含要作为[] byte字段的字符串，我想将其编码为JSON.但是，生成的JSON包含切片内容的非预期字符串表示形式.这是我所引用的示例:

package main

import (
    "fmt"
    "encoding/json"
    )

type Msg struct {
    Content []byte
}

func main() {
    helloStr := "Hello"
    helloSlc := []byte(helloStr)
    fmt.Println(helloStr, helloSlc)

    obj := Msg{helloSlc}
    json, _ := json.Marshal(obj)
    fmt.Println(string(json))
}

这将产生以下输出:

Hello [72 101 108 108 111]
{"Content":"SGVsbG8="}

json.Marshal()方法执行哪种转换? []字节编码的字符串.如何使用字符串{"Content":"Hello"}的原始内容生成JSON?

解决方案

[]byte被编组为base64编码的字符串.从文档:

数组和切片值编码为JSON数组，但[]byte编码为base64编码的字符串，而nil slice编码为空JSON对象.

未编组时，这些值会正确解码.

完成此操作的原因是JSON没有原始字节的本地表示形式.有关详细说明，请参见此问题. >

I have a struct containing strings as []byte fields which I'd like to encode into JSON. However, the generated JSON contains a non expected string representation of the slice contents. Here is an example of what I refer:

package main

import (
    "fmt"
    "encoding/json"
    )

type Msg struct {
    Content []byte
}

func main() {
    helloStr := "Hello"
    helloSlc := []byte(helloStr)
    fmt.Println(helloStr, helloSlc)

    obj := Msg{helloSlc}
    json, _ := json.Marshal(obj)
    fmt.Println(string(json))
}

This produces the following output:

Hello [72 101 108 108 111]
{"Content":"SGVsbG8="}

What kind of conversion is the json.Marshal() method performing to the []byte encoded string. How can I generate a JSON with the original content of my string {"Content":"Hello"}?

解决方案

A []byte is marshalled as base64 encoded string. From the documentation:

Array and slice values encode as JSON arrays, except that []byte encodes as a base64-encoded string, and a nil slice encodes as the null JSON object.

These values are decoded properly when unmarshalled.

The reason why this is done is that JSON does not have a native representation for raw bytes. See this question for a detailed explanation.

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