Question

你好我有2个实体

主要实体

@Entity
@Table(name = "Events")
public class Event {

//Some fields ...

@ManyToMany(cascade = CascadeType.ALL)
@JoinTable(name = "event_eventtypes" ,
        joinColumns = @JoinColumn(name = "event_id"),
inverseJoinColumns = @JoinColumn(name = "event_type_id"))
private Set<EventType> eventTypes;

//Getters and setters...

现在我有一个使用spring form-taglib

创建的表单

<form:form modelAttribute="event" method="post" action="/event/registerEvent" commandName="event">

<form:label path="name">Event display name</form:label>
<form:input  path="name" type="text" cssClass="form-control" placeholder="Display name"/>

<form:label path="description" >Description</form:label>
<form:textarea path="description" cssClass="form-control"/>

<form:label path="priv" cssClass="">Make private? <span style="font-family:'Open Sans', sans-serif; font-size:11px; color: dodgerblue;">(It will be seen by your friends and people who you send invitation.)</span></form:label>       
<form:checkbox path="priv" cssClass="form-check-input"/>

<form:label path="age">Age limit</form:label>
<form:select path="age">
  <form:options items="${age}"/>
</form:select>


<form:hidden path="lng" id="formLang" />
<form:hidden path="lat" id="formLat"/>
<%--Question appear here--%>
<form:select path="eventTypes" items="${eventTypes}" multiple="true"/>

<input type="submit" value="Submit">

控制器

@Controller
public class EventController {

   private static final Logger logger = LoggerFactory.getLogger(EventController.class);

   @Autowired
   private EventService eventService;
   @Autowired
   private UserService userService;
   @Autowired
   private EventTypeService eventTypeService;

   @RequestMapping(path = "/event/create", method = RequestMethod.GET)
   public String init(ModelMap modelMap) {
       List<String> tags = eventTypeService.listEventTypes().stream().map(EventType::getName).collect(Collectors.toList());
       ArrayList<Integer> ageArr = new ArrayList();
       ageArr.add(0);
       ageArr.add(6);
       ageArr.add(12);
       ageArr.add(16);
       ageArr.add(18);
       modelMap.addAttribute("event", new Event());
       modelMap.addAttribute("age", ageArr);
       modelMap.addAttribute("eventTypes", tags);
       return "/event/create";
   }

   @RequestMapping(path = "/event/registerEvent", method = RequestMethod.POST)
   public String createEvent(@ModelAttribute("event") Event event, @ModelAttribute("eventTypes1") List<String> eventTypes){
       event.setDate(new Date());
       event.setUser(userService.getUserByUsername(
            AuthenticationService.getLoggedInUser())
       );
       eventService.addEvent(event);

       return "redirect:/";
   }

完成包含值的表单后，单击“提交”，“获取错误”

400客户端发送的请求在语法上是不正确的。

因为eventTypes属性是String类型。如何将该列表作为控制器中的另一个参数发送，或者我应该怎么做？

Answer 1

也许你需要一个DTO来包含事件和事件类型列表。

Answer 2

当我这样做时，我发送一个DTO，其中包含事件类型的ID /字符串列表到表单，然后从DTO创建一个新事件。

对于select语句，循环遍历DTO中返回的每个选项，并使用服务findById检索每个eventType，然后将其添加到事件模型中。

for (String tag : eventDTO.getEventTags()) {

    EventType eventTag = eventTypeService.findById(Long.valueOf(tag));

    if (eventTag != null) {
        event.getEventTypes().add(eventTag );
    }
}

Answer 3

找到了解酒。只需将基于jsp的表单实现为：

<form:form modelAttribute="event" method="post" action="/event/registerEvent" commandName="event">

     ... 

    <%--There I'm not using more jsp tabs.--%>
    <select multiple name="et" id="tags">
       <c:forEach items="${eventTypes}" var="e">
           <option value=${e}>${e}</option>
       </c:forEach>
    </select>

    <input type="submit" value="Submit">
</form:form>

在Controller中我获取参数request.getParameterValues("et")) - 从HttpServletRequest返回String[]

如何在POST请求中继续处理复杂对象

3 个答案: