动态更改视图中的选择标记

Question

我有以下模型，Major，University和Application。在创建新的应用程序时，我希望包含该应用程序的主要列表根据大学字段的选择动态更改。

我在我的代码中使用了dojo，但它无法正常工作..

创建应用程序标记

<?xml version="1.0" encoding="UTF-8" standalone="no"?>
<div xmlns:c="http://java.sun.com/jsp/jstl/core"
    xmlns:field="urn:jsptagdir:/WEB-INF/tags/form/fields"
    xmlns:form="urn:jsptagdir:/WEB-INF/tags/form"
    xmlns:jsp="http://java.sun.com/JSP/Page"
    xmlns:spring="http://www.springframework.org/tags" version="2.0">
    <jsp:directive.page contentType="text/html;charset=UTF-8" />
    <jsp:output omit-xml-declaration="yes" />
    <spring:url value="/applications/majorsByUniversity?university="
        var="ajax_url" />
    <script type="text/javascript">
        // DOM is ready
        dojo.addOnLoad(function() {
            var universityID = dijit.byId("_university_id");                            
            //var majors = dijit.byId("_majors_id");
            var _fragment_item_ = dojo.byId("_fragment_item_");
            dojo.connect(universityID, "onChange", function(evt) {
                var url = "${ajax_url}?university=" + universityID.get("Value");
                dojo.xhrGet({url : "applications/majorsbyuniversity", timeout : 2000, content : {
                    universityId : dojo.trim(universityID.value)}, load : function(result) {
                        _fragment_item_.innerHTML = "" + result;
                        Spring.addDecoration(new Spring.ElementDecoration({
                            elementId : '_major_id',
                            widgetType : 'dijit.form.FilteringSelect',
                            widgetAttrs : {
                                hasDownArrow : true
                            }
                        }));
                    }
                });
            });
        });

    </script>
    <form:create id="fc_eu_gju_domain_Application"
        modelAttribute="application" path="/applications"
        render="${empty dependencies}" z="kI5rm14J9r0TDsEBqiWG5a6bVnw=">
        <field:input field="status" id="c_eu_gju_domain_Application_status"
            z="v09RNw9OQd32sgV0gnb/TcG4NLY=" />
        <field:select field="university"
            id="c_eu_gju_domain_Application_university" itemValue="id"
            items="${universitys}" path="/universitys"
            z="O6M+L2bFaYs9ILR85JMqyqOe3jg=" />

        <div id="_fragment_item_">
            <field:select field="majors" id="c_eu_gju_domain_Application_majors"
            itemValue="id" items="${result}" multiple="true" path="/majors"
            z="SToc0qAE7C9u/cHqpb1wizsN1N0=" />
        </div>

    </form:create>
    <form:dependency dependencies="${dependencies}"
        id="d_eu_gju_domain_Application" render="${not empty dependencies}"
        z="zaFd2zq80iviSNmKnrMKaVLPQQY=" />
</div>

Application.java

@RooJavaBean
@RooToString
@RooJpaActiveRecord
public class Application {

    private String status;


    @ManyToOne
    private University university;

    @ManyToMany(cascade = CascadeType.ALL)
    private Set<Major> majors = new HashSet<Major>();
}

ApplicationController.java

@RequestMapping("/applications")
@Controller
@RooWebScaffold(path = "applications", formBackingObject = Application.class)
public class ApplicationController {
    public @ResponseBody List<Major> majorsByUniversity(@RequestParam Long universityId) {

        List<Major> majors = Major.findMajorsByUniversity(University.findUniversity(universityId)).getResultList();
        return majors;
}