没有空值的 Gson 转换器

如何解决没有空值的 Gson 转换器

我有两个 apis ，一个向我发送一个 Appointment 对象，它的主体是这样的

<script>
      let calendar = null;
      $(document).ready(function() {
        let calendarEl = $('#calendar')[0];
        calendar = new FullCalendar.Calendar(calendarEl,{
          headerToolbar: {
            left: 'prev,next today',center: 'title',right: 'dayGridMonth,dayGridWeek,customDayView'
          },eventOrder: 'start',initialView: 'dayGridMonth',events: {
            url: '{{ path('apps_scheduler_pro_events') }}',method: 'POST',failure: function() {
              alert('There was an error while fetching events');
            },},customButtons: {
            customDayView: {
              text: 'day',click: function() {
                window.location = "{{ path('apps_scheduler_pro_day') }}";
              }
            }
          },datesSet: function(dateInfo) {
            console.log('dateSet');
            calendar.removeAllEvents();
            calendar.refetchEvents();
          },eventClick: function(event) {
            // https://stackoverflow.com/questions/58485165/fullcalendar-how-to-have-event-opening-in-new-tab-window-calendar-view
            if (event.event.url) {
              event.jsEvent.preventDefault();
              window.open(event.event.url,"_blank");
            }
          },eventDidMount: function (info) {
            let html = `
<div class="fc-event-main">
                <div class="fc-event-main-frame">
                    <div class="fc-event-title-container">
                        <div class="fc-event-title fc-sticky" style="padding-left: 12px;">
` + info.event.title + `
<div style="position: absolute; left: 0; top: 0; width: 10px; height: 100%;">&nbsp;</div>
                        </div>
                    </div>
                </div>
            </div>
            `;
            $(info.el).html(html);
          },});
        calendar.render();
      });

      function RefreshCalendar() {
        calendar.refetchEvents();
      }
    </script>

另一个应该从我这里收到这个身体

data class Appointment(
    id:Long = 4,name:String = "name"
   ...
)

没有id字段 在 kotlin 代码中，我想将 Id 设置为 null 并且 Gson 应该忽略它，因为它是 null 怎么做 ？ 如何在没有空值的情况下将 kotlin 类转换为 json

解决方法

Gson 默认跳过空值。假设您有一个 id 可为空的 Appointment 类：

data class Appointment(
    val id: Long?,val name: String,)

如果id为null，则不会出现在json中：

val gson = Gson()
gson.toJson(Appointment(null,"hello")) // => {"name":"hello"}

如果要序列化空值，请在 gson builder 中使用 serializeNulls() 方法：

val gson = GsonBuilder().serializeNulls().create()
gson.toJson(Appointment(null,"hello")) // => {"id":null,"name":"hello"}