golang中 将string转化为json

func str2json(){
    cmd := "['read': 2.0, 'write': 1.2}, {'read_mb': 4.0, 'write': 3.2}]"
    str := strings.Replace(string(cmd), "'", "\"", -1)
    str = strings.Replace(str, "\n", "", -1)


    var dat []map[string]interface{}
    if err := json.Unmarshal([]byte(str), &dat); err == nil {
        fmt.Println(dat)
        //fmt.Println(dat["status"])
    } else {
        fmt.Println(err)
    }
}