golang-利用反射给结构体赋值

由于想给一个结构体的部分成员赋值，但是有不知道具体名字，故将tag的json名字作为索引，按照json名字来一一赋值

1.通过tag反射
//将结构体里的成员按照json名字来赋值
func SetStructFieldByJsonName(ptr interface{}, fields map[string]interface{}) {
    logger.Debug("fields:", fields)

    v := reflect.ValueOf(ptr).Elem() // the struct variable

    for i := 0; i < v.NumField(); i++ {

        fieldInfo := v.Type().Field(i) // a reflect.StructField
        tag := fieldInfo.Tag           // a reflect.StructTag
        name := tag.Get("json")

        if name == "" {
            name = strings.ToLower(fieldInfo.Name)
        }
        //去掉逗号后面内容 如 `json:"voucher_usage,omitempty"`
        name = strings.Split(name, ",")[0]
        logger.Debug("JSONnAME:", name)

        if value, ok := fields[name]; ok {

            logger.Debug("fieldInfo.Name:", fieldInfo.Name)
            //给结构体赋值
            //保证赋值时数据类型一致
            logger.Debug("类型1：", reflect.ValueOf(value).Type(), "类型2：", v.FieldByName(fieldInfo.Name).Type())
            if reflect.ValueOf(value).Type() == v.FieldByName(fieldInfo.Name).Type() {
                v.FieldByName(fieldInfo.Name).Set(reflect.ValueOf(value))
            }

        }
    }

    return
}

 2.通过结构体字段名称进行反射

// 通过反射，对user进行赋值
type user struct{
    name string
    age int
    feature map[string]interface{}
}


func main() {
    var u interface{}
    u=new(user)
    value:=reflect.ValueOf(u)
    if value.Kind()==reflect.Ptr{
        elem:=value.Elem()
        name:=elem.FieldByName("name")
        if name.Kind()==reflect.String{
            *(*string)(unsafe.Pointer(name.Addr().Pointer())) = "fangwendong"
        }

        age:=elem.FieldByName("age")
        if age.Kind()==reflect.Int{
            *(*int)(unsafe.Pointer(age.Addr().Pointer())) =24
        }

        feature:=elem.FieldByName("feature")
        if feature.Kind()==reflect.Map{
            *(*map[string]interface{})(unsafe.Pointer(feature.Addr().Pointer())) =map[string]interface{}{
                "爱好":"篮球",
                "体重":60,
                "视力":5.2,
            }
        }

    }

    fmt.Println(u)
}