jquery - 无法使用 jQuery 加载 JSON 上的完整数据

Question

我正在尝试将 Json 与 struts 2 和 jquery 一起使用，我能够达到一定水平，但过去两天我一直遇到一些问题。这是我为此使用的代码和配置

<package name="default" extends="struts-default,json-default" namespace="/">    

    <result-types>
        <result-type name="tiles" class="org.apache.struts2.views.tiles.TilesResult"></result-type>
    </result-types>

    <action name="showUpdateAjax" class="courseCreateAction" method="showUpdateAjax">
            <result type="json">
                <param name="includeProperties">courseInfo, fetchedAllSubjects, selectedFetchedSubs, subjectList, fetchedAllExamType, examTypeList, selectedExmTypes, fetchedAllCourse, isUpdate, btnPressed, updateCourseId, nextCourse, previousCourse</param>
                <param name="prefix">true</param>
                <param name="ignoreHierarchy">false</param>
            </result>
    </action>

这是我这部分的 Jsp 代码

<tr><td><input type="submit" value="Refresh" onclick="refreshData()" id="refreshBtn"/></td></tr>

    <tr><td><s:a href="/SASIS/showUpdateAjax.action?updateCourseId=4">click Here 2</s:a></td></tr>
</table>
</center>
<script type="text/javascript"> 
    $(document).ready(function(){
            $("#refreshBtn").click(function(){
                $.getJSON("/SASIS/showUpdateAjax.action?updateCourseId=4",function(data){
                    alert('its working '+data);

                    });

                });
        });
</script>

这是我的java代码

public class CourseCreateAction extends ActionSupport implements ServletRequestAware{
private CourseInfo courseInfo;
private List fetchedAllSubjects;
private List<SubjectInfo> selectedFetchedSubs;
private List subjectList;
private List fetchedAllExamType;
private List examTypeList;
private List<ExamType> selectedExmTypes;
private List fetchedAllCourse;
private String nextCourse;
private String previousCourse;
private DAOInterface dao;
private String btnPressed;
private String updateCourseId;  
private HttpServletRequest request; 
private boolean isUpdate;

public void setServletRequest(HttpServletRequest request) {
    request=request;
}

public List getFetchedAllSubjects() {
    return fetchedAllSubjects;
}

public void setFetchedAllSubjects(List fetchedAllSubjects) {
    this.fetchedAllSubjects = fetchedAllSubjects;
}

public List<SubjectInfo> getSelectedFetchedSubs() {
    return selectedFetchedSubs;
}

public void setSelectedFetchedSubs(List<SubjectInfo> selectedFetchedSubs) {
    this.selectedFetchedSubs = selectedFetchedSubs;
}

public List getSubjectList() {
    return subjectList;
}

public void setSubjectList(List subjectList) {
    this.subjectList = subjectList;
}

public CourseInfo getCourseInfo() {
    return courseInfo;
}

public void setCourseInfo(CourseInfo courseInfo) {
    this.courseInfo = courseInfo;
}
public List getFetchedAllExamType() {
    return fetchedAllExamType;
}

public void setFetchedAllExamType(List fetchedAllExamType) {
    this.fetchedAllExamType = fetchedAllExamType;
}

public List getExamTypeList() {
    return examTypeList;
}

public void setExamTypeList(List examTypeList) {
    this.examTypeList = examTypeList;
}

public List<ExamType> getSelectedExmTypes() {
    return selectedExmTypes;
}

public void setSelectedExmTypes(List<ExamType> selectedExmTypes) {
    this.selectedExmTypes = selectedExmTypes;
}

public List getFetchedAllCourse() {
    return fetchedAllCourse;
}

public void setFetchedAllCourse(List fetchedAllCourse) {
    this.fetchedAllCourse = fetchedAllCourse;
}

public String getNextCourse() {
    return nextCourse;
}

public void setNextCourse(String nextCourse) {
    this.nextCourse = nextCourse;
}

public String getPreviousCourse() {
    return previousCourse;
}

public void setPreviousCourse(String previousCourse) {
    this.previousCourse = previousCourse;
}

public DAOInterface getDao() {
    return dao;
}

public void setDao(DAOInterface dao) {
    this.dao = dao;
}

public String getBtnPressed() {
    return btnPressed;
}

public void setBtnPressed(String btnPressed) {
    this.btnPressed = btnPressed;
}

public String getUpdateCourseId() {
    return updateCourseId;
}

public void setUpdateCourseId(String updateCourseId) {
    this.updateCourseId = updateCourseId;
}

public boolean getIsUpdate() {
    return isUpdate;
}

public void setIsUpdate(boolean isUpdate) {
    this.isUpdate = isUpdate;
}

public String showUpdateAjax(){
        try{
        System.out.println("Ajax calling...........");
        showUpdateCourse();
        }catch (Exception e) {
            e.printStackTrace();
        }
        return SUCCESS;
    }

public String showUpdateCourse(){
    try {
        isUpdate=true;
        courseInfo=dao.getCourse(Integer.parseInt(updateCourseId));
        System.out.println(courseInfo.getCourseId());
        selectedFetchedSubs=courseInfo.getSubjectList();
        selectedExmTypes=courseInfo.getExamTypeList();
        fetchedAllSubjects=dao.getAllSubjects();
        fetchedAllExamType=dao.getActiveExamTypes();
        for(ExamType exmType:selectedExmTypes)
            for (int i = 0; i < fetchedAllExamType.size(); i++) {
                if(exmType!=null&&((ExamType)fetchedAllExamType.get(i)).getExamTypeId()==exmType.getExamTypeId()){
                    fetchedAllExamType.remove(i);
                    break;
                }
            }
        for(SubjectInfo subInfo:selectedFetchedSubs)
            for (int i = 0; i < fetchedAllSubjects.size(); i++) {
                if(subInfo!=null&&((SubjectInfo)fetchedAllSubjects.get(i)).getSubjectId()==subInfo.getSubjectId()){
                    fetchedAllSubjects.remove(i);
                    break;
                }
            }
    } catch (Exception e) {
        e.printStackTrace();
    }
    return SUCCESS;
}

我也在项目中使用了spring和hibernate。在执行此操作时，当我单击调用 showUpdateAction.action 的链接时，我得到了如下响应

{}&& {"btnPressed":null,"courseInfo":{},"examTypeList":null,"fetchedAllCourse":[],"fetchedAllExamType":[],"fetchedAllSubjects":[],"isUpdate":true,"nextCourse":null,"previousCourse":null,"selectedExmTypes":[],"selectedFetchedSubs":[],"subjectList":null,"updateCourseId":"4"}

但是当我单击按钮时，它没有显示任何内容，但该函数被调用。此外，这里的 CourseInfo 是一个对象，其中有带有 setter getter 方法的变量，并且当调用 showUpdateAction.action 时该对象处于满状态，但在输出中我们可以看到 courseInfo 带有空花括号。请帮助解决这个问题我已经浏览了几篇文章并用谷歌搜索了很多。现在除了询问我别无选择。请帮忙

Answer 1

我看了你的代码(对struts一无所知)，我注意到，

<action name="showUpdateAjax" class="courseCreateAction" method="showUpdateAjax">

你的ajax调用是，

"/SASIS/showUpdateAjax.action?updateCourseId=4"

我相信您的 Controller 是“courseCreateAction”，操作是“showUpdateAjax”，典型的 GET url 看起来像 /controller/action?param1=value1&param2=value2...

但是您的网址不包含 Controller 。

处理此请求的操作，

public String showUpdateAjax(){
  try{
  System.out.println("Ajax calling...........");
  showUpdateCourse();
  }catch (Exception e) {
      e.printStackTrace();
  }
  return SUCCESS;
}

courseId 在哪里传递给 showUpdateAjax() ？

最后，就像 mprabhat 提到的那样，您已经绑定(bind)了按钮以在单击时触发 ajax 调用。所以不需要 onclick="refreshData()"