1

我有这个 JDO 服务返回List<Order>：

public List<Order> getOnGoingOrders() {

        List<Order> orderList = null;
        JDOPersistenceManager pm = (JDOPersistenceManager) persistenceManager.getPM();

        try {

            Query<Order> q = pm.newQuery(Order.class);

            q.setFilter("orderStatus != 'COMPLETED' && orderStatus != 'CANCELLED'");
            q.setOrdering("orderPlacedTime desc");

            orderList = (List<Order>) q.execute();

        } catch (Exception e) {
            e.printStackTrace();
        }

        return orderList;
    }

当前端调用Collections#sort()它时，我得到以下异常：

 com.sun.faces.application.view.FaceletViewHandlingStrategy handleRenderException
SEVERE: Error Rendering View[/index.xhtml]
java.lang.UnsupportedOperationException: Query result sets are not modifiable
    at org.datanucleus.store.query.AbstractQueryResultIterator.set(AbstractQueryResultIterator.java:86)
    at java.util.List.sort(List.java:482)
    at java.util.Collections.sort(Collections.java:175)
    at org.primefaces.component.datatable.feature.SortFeature.singleSort(SortFeature.java:148)
    at org.primefaces.component.datatable.feature.SortFeature.encode(SortFeature.java:106)
    at org.primefaces.component.datatable.DataTableRenderer.encodeEnd(DataTableRenderer.java:80)
    at javax.faces.component.UIComponentBase.encodeEnd(UIComponentBase.java:920)
    at javax.faces.component.UIComponent.encodeAll(UIComponent.java:1863)
    at com.sun.faces.context.PartialViewContextImpl$PhaseAwareVisitCallback.visit(PartialViewContextImpl.java:582)
    at com.sun.faces.component.visit.PartialVisitContext.invokeVisitCallback(PartialVisitContext.java:183)
    at org.primefaces.component.api.UIData.visitTree(UIData.java:827)
    at javax.faces.component.UIComponent.visitTree(UIComponent.java:1700)
    at javax.faces.component.UIForm.visitTree(UIForm.java:371)
    at javax.faces.component.UIComponent.visitTree(UIComponent.java:1700)
    at javax.faces.component.UIComponent.visitTree(UIComponent.java:1700)
    at org.primefaces.component.api.UITabPanel.visitTree(UITabPanel.java:920)
    at javax.faces.component.UIComponent.visitTree(UIComponent.java:1700)
    at javax.faces.component.UIComponent.visitTree(UIComponent.java:1700)
    at com.sun.faces.context.PartialViewContextImpl.processComponents(PartialViewContextImpl.java:403)
    at com.sun.faces.context.PartialViewContextImpl.processPartial(PartialViewContextImpl.java:322)
    at org.primefaces.context.PrimePartialViewContext.processPartial(PrimePartialViewContext.java:57)
    at javax.faces.context.PartialViewContextWrapper.processPartial(PartialViewContextWrapper.java:219)
    at org.omnifaces.context.OmniPartialViewContext.processPartial(OmniPartialViewContext.java:139)
    at javax.faces.component.UIViewRoot.encodeChildren(UIViewRoot.java:1004)
    at javax.faces.component.UIComponent.encodeAll(UIComponent.java:1856)
    at com.sun.faces.application.view.FaceletViewHandlingStrategy.renderView(FaceletViewHandlingStrategy.java:432)
    at com.sun.faces.application.view.MultiViewHandler.renderView(MultiViewHandler.java:134)
    at javax.faces.application.ViewHandlerWrapper.renderView(ViewHandlerWrapper.java:337)
    at javax.faces.application.ViewHandlerWrapper.renderView(ViewHandlerWrapper.java:337)
    at javax.faces.application.ViewHandlerWrapper.renderView(ViewHandlerWrapper.java:337)
    at javax.faces.application.ViewHandlerWrapper.renderView(ViewHandlerWrapper.java:337)
    at org.omnifaces.viewhandler.NoAutoGeneratedIdViewHandler.renderView(NoAutoGeneratedIdViewHandler.java:93)
    at javax.faces.application.ViewHandlerWrapper.renderView(ViewHandlerWrapper.java:337)
    at com.sun.faces.lifecycle.RenderResponsePhase.execute(RenderResponsePhase.java:120)
    at com.sun.faces.lifecycle.Phase.doPhase(Phase.java:101)
    at com.sun.faces.lifecycle.LifecycleImpl.render(LifecycleImpl.java:219)
    at org.apache.deltaspike.jsf.impl.listener.request.DeltaSpikeLifecycleWrapper.render(DeltaSpikeLifecycleWrapper.java:111)
    at javax.faces.lifecycle.LifecycleWrapper.render(LifecycleWrapper.java:92)
    at org.apache.deltaspike.jsf.impl.listener.request.JsfClientWindowAwareLifecycleWrapper.render(JsfClientWindowAwareLifecycleWrapper.java:160)
    at javax.faces.webapp.FacesServlet.service(FacesServlet.java:659)
    at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:291)
    at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:206)
    at org.apache.tomcat.websocket.server.WsFilter.doFilter(WsFilter.java:52)
    at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:239)
    at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:206)
    at org.apache.shiro.web.servlet.AbstractShiroFilter.executeChain(AbstractShiroFilter.java:449)
    at org.apache.shiro.web.servlet.AbstractShiroFilter$1.call(AbstractShiroFilter.java:365)
    at org.apache.shiro.subject.support.SubjectCallable.doCall(SubjectCallable.java:90)
    at org.apache.shiro.subject.support.SubjectCallable.call(SubjectCallable.java:83)
    at org.apache.shiro.subject.support.DelegatingSubject.execute(DelegatingSubject.java:383)
    at org.apache.shiro.web.servlet.AbstractShiroFilter.doFilterInternal(AbstractShiroFilter.java:362)
    at org.apache.shiro.web.servlet.OncePerRequestFilter.doFilter(OncePerRequestFilter.java:125)
    at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:239)
    at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:206)
    at org.apache.catalina.core.StandardWrapperValve.invoke(StandardWrapperValve.java:219)
    at org.apache.catalina.core.StandardContextValve.invoke(StandardContextValve.java:106)
    at org.apache.catalina.authenticator.AuthenticatorBase.invoke(AuthenticatorBase.java:502)
    at org.apache.catalina.core.StandardHostValve.invoke(StandardHostValve.java:142)
    at org.apache.catalina.valves.ErrorReportValve.invoke(ErrorReportValve.java:79)
    at org.apache.catalina.valves.AbstractAccessLogValve.invoke(AbstractAccessLogValve.java:610)
    at org.apache.catalina.core.StandardEngineValve.invoke(StandardEngineValve.java:88)
    at org.apache.catalina.connector.CoyoteAdapter.service(CoyoteAdapter.java:518)
    at org.apache.coyote.http11.AbstractHttp11Processor.process(AbstractHttp11Processor.java:1091)
    at org.apache.coyote.AbstractProtocol$AbstractConnectionHandler.process(AbstractProtocol.java:668)
    at org.apache.coyote.http11.Http11NioProtocol$Http11ConnectionHandler.process(Http11NioProtocol.java:223)
    at org.apache.tomcat.util.net.NioEndpoint$SocketProcessor.doRun(NioEndpoint.java:1517)
    at org.apache.tomcat.util.net.NioEndpoint$SocketProcessor.run(NioEndpoint.java:1474)
    at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1142)
    at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:617)
    at org.apache.tomcat.util.threads.TaskThread$WrappingRunnable.run(TaskThread.java:61)
    at java.lang.Thread.run(Thread.java:745)

这是如何引起的，我该如何解决？

4

2 回答 2

4

我不知道您正在使用的 Persistance Manager (JDO)，但查询返回的结果列表似乎不可修改（您可能可以在 JDO 文档中阅读相关内容）。

尝试创建一个新列表，对查询结果执行 addAll()，然后使用该列表。

于 2016-06-20T13:53:10.347 回答
0

我认为这不是 Primefaces / JSF 问题。排序功能太微不足道了。乍一看，您的 xhtml 看起来不错。

尝试将列表初始化为空列表，例如

private ArrayList<Order> orders = new ArrayList<order>()

..在加载数据之前。因此，您可以确保永远不会有“空列表”。此外，您是否检查过数据是否已正确加载？否则，尝试通过 检索数据q.getResultList()。在我的情况下，我一直使用这种方法并且没有任何问题。另一个提示：尝试将检索到的列表从 DB 复制到一个额外的返回列表（如安全副本）addAll()并返回该列表。

于 2016-06-20T14:36:36.237 回答