如何创建可由Gin序列化到json的排序键值映射

在我的例子中，解决方案是在sortedmap.SortedMap左右编写一个包装器，并为此包装器编写一个定制MarshalJSON:

type TopicBundle struct {
    Content      SortedMapWrapper `json:"content"`
}
type SortedMapWrapper struct {
    topics *sortedmap.SortedMap
}

func (wrapper SortedMapWrapper) MarshalJSON() ([]byte, error) {
    var sb strings.Builder
    var counter = 0
    sb.WriteString("{")
    for _, key := range wrapper.topics.Keys() {
        sb.WriteString("\"")
        sb.WriteString(key.(string))
        sb.WriteString("\":")
        sb.Write(first(json.Marshal(first(wrapper.topics.Get(key)))))
        counter += 1
        if counter < wrapper.topics.Len() {
            sb.WriteString(",")
        }
    }
    sb.WriteString("}")
    return []byte(sb.String()), nil
}
func loadTopic(c *gin.Context) {
    var contentMap = sortedmap.New(1, comparisonFunc)
    contentMap.Insert("val1", Topic{"val1", "val2", "val3"})
    contentMap.Insert("val33", Topic{"val1", "val2", "val3"})
    var topicBundle = TopicBundle{}
    topicBundle.Content = SortedMapWrapper{contentMap}
    c.JSON(200, topicBundle)
}

注意，MarshalJSON的定义应该使用SortedMapWrapper(not *SortedMapWrapper).否则它不会被发现.