如何替换json字符串和正则表达式中的双引号?

How do I replace a double quote in json string and regular expressions?

Input Json is:

"RegDateTime" : 1481641851263, "Code":"123213",....

and Output should be:

"RegDateTime" : "1481641851263", "Code":"123213",....

I want to fix only json key value that is RegDateTime.
Please suggest any regular expression and replace with double quote in go language.

func ReplaceAllNumber(json string)(string) {
    re := regexp.MustCompile("(:\\s*)(\\d+)(\\s*[,}\\]])")
    return re.ReplaceAllString(json, "$1\"$2\"$3")
}


func ReplaceNumberWithField(json string, fieldName string)(string) {
    regString := fmt.Sprintf("(\"%s\"\\s*:\\s*)(\\d+)(\\s*[,}\\]])", fieldName)

    re := regexp.MustCompile(regString)
    return re.ReplaceAllString(json, "$1\"$2\"$3")
}

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