Question

我有一个带有hibernate web应用程序的spring。在其中一个页面中，我有列表框，其中包含多个主题。在同一页面中，我有一个textarea和4个text-box，其中我将在4个文本框中输入问题文本textarea和问题选项。我的目的是当我点击提交按钮时，我想将问题和它的4个选项以及所选主题存储到数据库中。

问题模型类：

@Entity
@Table(name="QUESTION")
public class Question 
{
  @Id
  @Column(name="questionId")
  @GeneratedValue(strategy=GenerationType.IDENTITY)
  private long questionId;
  @Column(length=1000)
  private String questionText;
  private String choiceOne;
  private String choiceTwo;
  private String choiceThree;
  private String choiceFour;
  private String choiceFive;
  private String answer;
  private String explanation;
  private boolean status;
  @ManyToMany(fetch = FetchType.LAZY , cascade = CascadeType.ALL)
  @JoinTable(name = "QSUBJECTTAG", joinColumns = { @JoinColumn (name = "questionId")}, inverseJoinColumns = { @JoinColumn(name = "subjectId")})
  private Set<Subject> subjects = new HashSet<Subject>();

//setter and getter methods for the fields
}

查看：question.jsp：

<c:url var="addAction" value="/question/add" ></c:url>

<form:form action="${addAction}" commandName="question">

<table border="1">
<tr>
    <c:if test="${!empty listSubjects}">
        <td colspan="2">
            <form:label path="subjects">
                <spring:message text="Subjects List"/>
            </form:label>
        </td>
        <td colspan="4">
        <form:select path="subjects" size="3" >
            <form:options items="${listSubjects}" itemValue="subjectId"  itemLabel="subjectDesc"/>
        </form:select>
        </td>
    </c:if>
    <c:if test="${empty listSubjects}">
        <td>
            <form:label path="questionId">
                <spring:message text="Question ID"/>
            </form:label>
        </td>
        <td>
        <form:select path="subjects">
            <form:option value="NONE">--Select Subject--</form:option>
        </form:select>
        </td>
    </c:if>

  </tr>
  <c:if test="${!empty question.questionText}">
  <tr>
    <td>
        <form:label path="questionId">
            <spring:message text="Question ID"/>
        </form:label>
    </td>
    <td>
        <form:input path="questionId" readonly="true" size="8"  disabled="true" />
        <form:hidden path="questionId" />
    </td> 
  </tr>
  </c:if>
  <tr rowspan="4">
    <td>
        <form:label path="questionText">
            <spring:message text="Question"/>
        </form:label>
    </td>
    <td colspan="6">
        <form:textarea path="questionText" size="1000" rows="20" cols="50"/>
    </td>

  </tr>
  <tr>  
    <td>
        <form:label path="choiceOne">
            <spring:message text="Choice One"/>
        </form:label>
    </td>
    <td>
        <form:textarea path="choiceOne" size="200"/>
    </td>
    <td>
        <form:label path="choiceTwo">
            <spring:message text="Choice Two"/>
        </form:label>
    </td>
    <td>
        <form:textarea path="choiceTwo" size="200"/>
    </td>
    <td>
        <form:label path="choiceThree">
            <spring:message text="Choice Three"/>
        </form:label>
    </td>
    <td>
        <form:textarea path="choiceThree" size="200"/>
    </td>
    <td>
        <form:label path="choiceFour">
            <spring:message text="Choice Four"/>
        </form:label>
    </td>
    <td>
        <form:textarea path="choiceFour" size="200"/>
    </td>
</tr> 
<tr>
    <td>
        <form:label path="answer">
            <spring:message text="Select Answer"/>
        </form:label>
    </td>
    <td>
        <form:select path="answer">
            <form:option value="NONE">--select the anser--</form:option>
            <form:option value="CHOICE_ONE">Choice One</form:option>
            <form:option value="CHOICE_TWO">Choice TWO</form:option>
            <form:option value="CHOICE_THREE">Choice Three</form:option>
            <form:option value="CHOICE_FOUR">Choice Four</form:option>
        </form:select>
    </td>
 </tr>
 <tr>
    <td colspan="2">
        <c:if test="${!empty question.answer}">
            <input type="submit"
                value="<spring:message text="Edit Question"/>" />
        </c:if>
        <c:if test="${empty question.answer}">
            <input type="submit"
                value="<spring:message text="Add Question"/>" />
        </c:if>
    </td>
 </tr> 
 </table>   
</form:form>

控制器：QuestionController.java

@Controller
public class QuestionController {


private QuestionService questionService;
private SubjectService subjectService;

@Autowired(required=true)
@Qualifier(value="questionService")
public void setQuestionService(QuestionService questionService)
{
    this.questionService = questionService;
}
@Autowired(required=true)
@Qualifier(value="subjectService")
public void setSubjectService(SubjectService subjectService)
{
    this.subjectService = subjectService;
}

@RequestMapping(value="/questions", method = RequestMethod.GET)
public String listQuestions(Model model)
{
    model.addAttribute("question",new Question());
    model.addAttribute("listSubjects", this.subjectService.listSubjects());
    return "questions";
}

//For add and update subject both
@RequestMapping(value= "/question/add", method = RequestMethod.POST)
public String addQuestion(@ModelAttribute("question") Question question){

    if(question.getQuestionId() == 0){
        //new Subject, add it
        this.questionService.addQuestion(question);
    }else{
        //existing subject, call update
        this.questionService.updateQuestion(question);
    }

    return "questions";

}
}

问题：我已将一些主题插入Subject表，并且视图页面中填充了带有插入主题的ListBox。现在，当我从ListBox中选择多个值并将一些数据输入到textarea和text-box时，所选主题不会被插入＆＃34;主题＆＃34; ＆＃34;问题＆＃34;类。如何捕获选定的选项并将其放入我的Question模型类字段Set<Subject> subjects = new HashSet<Subject>();？当我点击我的视图页面中的添加问题提交按钮时，我收到404 error with message "The request sent by the client was syntactically incorrect ()"

Answer 1

<强>解决方案

@InitBinder("question")
public void dataBinding(WebDataBinder binder){
    binder.registerCustomEditor(Set.class,"subjects", new CustomCollectionEditor(Set.class){
        @Override
        protected Object convertElement(Object element){
if (element!=null && element instanceof String){
                return  subjectService.getSubjectById(Long.parseLong((String)element));
            }
            return null;
        }
    });
}


@RequestMapping(value= "/questions/addQuestion", method = RequestMethod.POST)
public String addQuestion(@ModelAttribute("question") Question question,BindingResult result,Model model){

    if(question.getQuestionId() == 0){
        //new Subject, add it
        this.questionService.addQuestion(question);
    }else{
        //existing subject, call update
        this.questionService.updateQuestion(question);
    }

    return "redirect:/questions";

}

Spring MVC：将listBox选中（多个）值绑定到Controller类方法

1 个答案: