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我正在尝试使用单元格编辑器创建一个数据表。我有一个名为“组”的列，其中显示了组列表。单击单元格编辑器图标时，它会显示一个复选框菜单，用户可以在其中检查他们想要的任何组，然后单击提交。

我什至还没有我的 rowEditEvent 处理程序，并且我得到了一个集合不可修改的异常。我无法弄清楚我做错了什么，我得到了这个例外。

任何帮助表示赞赏。

group_admin.xhtml

<h:form>
    <p:dataTable value="#{userBacking.users}" var="users" editable="true">

        <p:column headerText="Groups">
            <p:cellEditor>
                <f:facet name="output">
                    <h:outputText value="#{users.groups}" />
                </f:facet>
                <f:facet name="input">
                    <p:selectCheckboxMenu value="#{users.groups}" label="Groups">
                        <f:selectItems value="#{groupBacking.groupsAsSelectItems}" />
                    </p:selectCheckboxMenu>
                </f:facet>
            </p:cellEditor>
        </p:column>

        <p:column headerText="Actions">
            <p:rowEditor />
        </p:column>

    </p:dataTable>
</h:form>

获取用户

public List<UserBean> getUsers() throws Exception {

        ContentManager cm = null;
        cm = getContentManager();

        if(users == null) {

            users = new ArrayList<UserBean>();

            UserManager um = cm.getUserManager();
            List<? extends Group> cmsGroups = um.getCmsDefinedGroups();
            List<? extends User> allUsers = um.getAllUsers(0, Integer.MAX_VALUE);

            // loop through each user
            for(User u : allUsers) {

                Set<? extends Group> groups = u.getGroups();

                UserBean user = new UserBean();
                user.setUserName(u.getUserName());
                user.setGroups(groups);  // THIS LINE CAUSES THE EXCEPTION
                users.add(user);
            }

        }

        return users;
    }

用户Bean

public class UserBean implements User {

        private String userName;
        private String firstName;
        private String lastName;
        private Set<? extends Group> groups = null;

        public UserBean() {}

        public UserBean(String userName, String firstName, String lastName, Set<? extends Group> groups) {
            this.userName = userName;
            this.firstName = firstName;
            this.lastName = lastName;
            this.groups = groups;
        }
        public void setUserName(String userName) {
            this.userName = userName;
        }
        public String getUserName() {
            return userName;
        }
        public String getFirstName() {
            return firstName;
        }
        public void setFirstName(String firstName) {
            this.firstName = firstName;
        }
        public String getLastName() {
            return lastName;
        }
        public void setLastName(String lastName) {
            this.lastName = lastName;
        }
        public Set<? extends Group> getGroups() {
            return groups;
        }
        public void setGroups(Set<? extends Group> groups) {
            this.groups = groups;
        }
        public void removeGroups() {
            groups = null;
        }

        @Override
        public boolean isDisabled() {
            // TODO Auto-generated method stub
            return false;
        }

        @Override
        public UserProfile getProfile() {
            // TODO Auto-generated method stub
            return null;
        }
    }

堆栈跟踪

Oct 9, 2012 1:09:08 PM com.sun.faces.renderkit.html_basic.MenuRenderer createCollection
SEVERE: Unable to create new Collection instance for type java.util.Collections$UnmodifiableSet
java.lang.InstantiationException: java.util.Collections$UnmodifiableSet
    at java.lang.Class.newInstance0(Class.java:340)
    at java.lang.Class.newInstance(Class.java:308)
    at com.sun.faces.renderkit.html_basic.MenuRenderer.createCollection(MenuRenderer.java:907)
    at com.sun.faces.renderkit.html_basic.MenuRenderer.convertSelectManyValuesForModel(MenuRenderer.java:367)
    at com.sun.faces.renderkit.html_basic.MenuRenderer.convertSelectManyValue(MenuRenderer.java:129)
    at com.sun.faces.renderkit.html_basic.MenuRenderer.getConvertedValue(MenuRenderer.java:315)
    at org.primefaces.component.selectcheckboxmenu.SelectCheckboxMenuRenderer.getConvertedValue(SelectCheckboxMenuRenderer.java:34)
    at javax.faces.component.UIInput.getConvertedValue(UIInput.java:1028)
    at javax.faces.component.UIInput.validate(UIInput.java:958)
    at javax.faces.component.UIInput.executeValidate(UIInput.java:1209)
    at javax.faces.component.UIInput.processValidators(UIInput.java:698)
    at javax.faces.component.UIComponentBase.processValidators(UIComponentBase.java:1086)
    at javax.faces.component.UIData.iterate(UIData.java:1501)
    at javax.faces.component.UIData.processValidators(UIData.java:1026)
    at com.sun.faces.context.PartialViewContextImpl$PhaseAwareVisitCallback.visit(PartialViewContextImpl.java:485)
    at com.sun.faces.component.visit.PartialVisitContext.invokeVisitCallback(PartialVisitContext.java:183)
    at javax.faces.component.UIData.visitTree(UIData.java:1233)
    at javax.faces.component.UIComponent.visitTree(UIComponent.java:1518)
    at javax.faces.component.UIForm.visitTree(UIForm.java:335)
    at javax.faces.component.UIComponent.visitTree(UIComponent.java:1518)
    at org.primefaces.component.tabview.TabView.visitTree(TabView.java:400)
    at javax.faces.component.UIComponent.visitTree(UIComponent.java:1518)
    at javax.faces.component.UIComponent.visitTree(UIComponent.java:1518)
    at com.sun.faces.context.PartialViewContextImpl.processComponents(PartialViewContextImpl.java:366)
    at com.sun.faces.context.PartialViewContextImpl.processPartial(PartialViewContextImpl.java:246)
    at javax.faces.context.PartialViewContextWrapper.processPartial(PartialViewContextWrapper.java:183)
    at javax.faces.component.UIViewRoot.processValidators(UIViewRoot.java:1163)
    at com.sun.faces.lifecycle.ProcessValidationsPhase.execute(ProcessValidationsPhase.java:76)
    at com.sun.faces.lifecycle.Phase.doPhase(Phase.java:101)
    at com.sun.faces.lifecycle.LifecycleImpl.execute(LifecycleImpl.java:118)
    at javax.faces.webapp.FacesServlet.service(FacesServlet.java:508)
    at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:290)
    at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:206)
    at org.primefaces.webapp.filter.FileUploadFilter.doFilter(FileUploadFilter.java:79)
    at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:235)
    at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:206)
    at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:235)
    at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:206)
    at org.apache.catalina.core.StandardWrapperValve.invoke(StandardWrapperValve.java:233)
    at org.apache.catalina.core.StandardContextValve.invoke(StandardContextValve.java:191)
    at org.apache.catalina.authenticator.AuthenticatorBase.invoke(AuthenticatorBase.java:563)
    at org.apache.catalina.core.StandardHostValve.invoke(StandardHostValve.java:127)
    at org.apache.catalina.valves.ErrorReportValve.invoke(ErrorReportValve.java:102)
    at org.apache.catalina.core.StandardEngineValve.invoke(StandardEngineValve.java:109)
    at org.apache.catalina.connector.CoyoteAdapter.service(CoyoteAdapter.java:293)
    at org.apache.coyote.http11.Http11Processor.process(Http11Processor.java:859)
    at org.apache.coyote.http11.Http11Protocol$Http11ConnectionHandler.process(Http11Protocol.java:602)
    at org.apache.tomcat.util.net.JIoEndpoint$Worker.run(JIoEndpoint.java:489)
    at java.lang.Thread.run(Thre

广告.java:662)

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1 回答 1

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堆栈跟踪表明u.getGroups()返回了一个Collections#unmodifiableSet(). 当 JSF 需要处理来自复选框组的提交值时，它会尝试实例化相同类型的集合，但该类型是不可实例化的。

将其包装在可修改的集合中，例如HashSet应该解决特定问题：

user.setGroups(new HashSet<Group>(groups));

与具体问题无关，到目前为止发布的代码中还有更多其他潜在问题，但它们与您遇到的特定异常无关。因此，修复当前问题可能会导致不同的异常，但这与当前问题完全无关。

于 2012-10-09T18:36:48.647 回答