Thymeleaf - SpringBoot中的绑定对象

Question

我使用Spring生成了一个Spring应用程序，使用了嵌入式Tomcat + Thymeleaf模板引擎，并将其打包为一个可执行的JAR文件。

所使用的技术：

Spring Boot 1.4.2 Thymeleaf，Spring 4.3.4 Thymeleaf，Thymeleaf 2.1.5 Thymeleaf，Tomcat Embed 8.5.6，Maven 3，Java 8

我有这门课

public class AlarmNotification {

    private Long id;

    private Action action;

    private Application aplication;

    private Device device;

    private TimeLapse timeLapse;

    private Guardian guardian;

    private List<SystemAlarm.Level> level;

    ...
}

而这个模板

<form class="form-style-9" action="#" th:action="@{/alarmNotification/save}" th:object="${alarmNotification}" method="post">
    <ul>
    <li>

       <input type="hidden" th:field="*{id}"       />

        <select name="device" class="field-style field-split align-left">
        <option value="ANDROID">ANDROID</option>
        <option value="IOS">IOS</option>
    </select>
       <select th:field="*{guardian}">
         <option th:each="guardian : ${guardians}" 
             th:value="${guardian.id}" 
             th:text="${guardian.name}"></option>
    </select>   
    </li>   
    <li>
       <select th:field="*{timeLapse}">
         <option th:each="timeLapse : ${timeLapses}" 
            th:value="${timeLapse.id}"
             th:text="${timeLapse.description}"></option>
    </select>   
    </li>
     <li>
       <select th:field="*{level}" multiple="multiple">
         <option th:each="level : ${alarmLevels}" 
             th:value="${level}" 
             th:text="${level}"></option>
    </select> 
    </li>
    <li>        
    </li>
    <li>
        <input type="submit" value="SAVE" />
    </li>
    </ul>
</form>

控制员：

@RequestMapping(value = { "/save" }, method = RequestMethod.POST)
    public String saveAlarmNotification (@Valid AlarmNotification alarmNotification, BindingResult bindingResult, Model model) throws DataAccessException, SQLException {

        System.out.println  ("<-------------------------------------->");
        System.out.println  (alarmNotification);
        System.out.println  ("<-------------------------------------->");
..
}

但是，除了设备和级别之外，对象alarmNotification的所有值都是空的：

 AlarmNotification [id=null, action=null, aplication=null,
 device=Device [id=null, deviceKey=ANDROID], 
timeLapse=null, guardian=null, 
level=[HIGH, MEDIUM, LOW]]

Answer 1

我认为在选择标记中th:value不正确，id没有正确设置。

对监护人来说应该是这样的

<select th:field="*{guardian}">
      <option th:each="guardian : ${guardians}" 
             th:value="${guardian.id}" 
             th:text="${guardian.name}"></option>
</select>

因为timeLapse应该是这样声明的

<select th:field="*{timeLapse}">
     <option th:each="timeLapse : ${timeLapses}" 
         th:value="${timeLapse.id}" 
         th:text="${timeLapse.description}"></option>
</select>  

在这个级别上，我认为你通过了错误的字段(看起来可能是那样的)

<select th:field="*{level}" multiple="multiple">
             <option th:each="level : ${alarmLevels}" 
                 th:value="${level}" 
                 th:text="${level}"></option>
        </select>

我希望这能帮到你。