json.Unmarshal到对象的json字符串为空结果 [英] json.Unmarshal json string to object is empty result

问题描述

我有一个非常简单的程序，如下所示:

I've got a very simple program like this:

package main

import (
    "encoding/json"
    "fmt"
)

type RunCommand struct{
    level string `json:"level"`
    caller string `json:"caller"`
    msg string `json:"msg"`
    cmd string `json:"cmd"`
}

func main() {
    content := `{"level":"info","caller":"my.go:10","msg":"run","cmd":"--parse"}`
    runCommand := RunCommand{}
    e := json.Unmarshal([]byte(content), &runCommand)
    if e != nil {
        fmt.Println("Unmarshal error")
    }
    fmt.Println(runCommand.level)
}

我希望可以将"content"内的所有json字段解析为"runCommand"对象，但实际上，最终的"fmt.Println"不会打印任何内容.我在哪里弄错了?

I wish that I could parse out all the json fields inside "content" into "runCommand" object, but actually, the final "fmt.Println" prints nothing. Where did I get wrong?

推荐答案

您必须具有如下导出的字段:

You have to have exported fields, like this:

type RunCommand struct{
    Level string `json:"level"`
    Caller string `json:"caller"`
    Msg string `json:"msg"`
    Cmd string `json:"cmd"`
}

，现在您可以使用:fmt.Println(runCommand.Level)否则json.Unmarshal将忽略未导出的字段.

and now you can use: fmt.Println(runCommand.Level) otherwise json.Unmarshal will ignore non-exported fields.

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