小贝子编程

将 filterBy 添加到 p：dataTable 会导致 java.lang.NullPointerException at javax.faces.component.StateHolderSa



我正在尝试开发一个延迟加载的数据表。未过滤和过滤的记录通过使用UserService（即简单的DAO）从持久性上下文中正确加载。我 100% 确定问题与正在使用的 DAO 无关，因为它已成功测试并部署在其他包中。

当我尝试插入过滤器时出现错误：过滤项目的集合已正确加载到页面上，但看起来在过程结束时出现问题并抛出 NPE。之后，表不再响应任何命令。

感谢您的任何帮助！

在下文中，配置、视图和正在使用的控制器。

配置

  • 野蝇 8.2.0
  • JDK 1.8.0_25
  • PrimeFaces 5.1

视图（XHTML 页面） 

<?xml version="1.0" encoding="UTF-8" ?>
<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd">
<html xmlns="http://www.w3.org/1999/xhtml"
      xmlns:ui="http://xmlns.jcp.org/jsf/facelets"
      xmlns:h="http://xmlns.jcp.org/jsf/html"
      xmlns:p="http://primefaces.org/ui">
    <ui:composition template="/template/template.xhtml">
        <ui:define name="body">
            <h:form id="UserListForm">
                <p:panel header="#{bundle.ListUserTitle}">
                    <p:dataTable id="UserTable" value="#{userController.users}" var="user" lazy="true" rows="25"
                                 paginator="true" rowKey="#{user.id}" selectionMode="single" selection="#{userController.selected}"
                                 paginatorTemplate="{RowsPerPageDropdown} {FirstPageLink} {PreviousPageLink} {CurrentPageReport} {NextPageLink} {LastPageLink}" >
                        <p:column headerText="#{bundle.User_id}" filterBy="#{user.id}">
                           <h:outputText value="#{user.id}"/>
                        </p:column>
                        <p:column headerText="#{bundle.User_nickname}" filterBy="#{user.nickname}">
                           <h:outputText value="#{user.nickname}"/>
                        </p:column>
                    </p:dataTable>
                </p:panel>
            </h:form>
        </ui:define>
    </ui:composition>
</html>

控制器

import java.io.Serializable;
import javax.annotation.PostConstruct;
import javax.inject.Named;
import javax.enterprise.context.SessionScoped;
import javax.inject.Inject;
import javax.transaction.Transactional;
@Named("userController")
@SessionScoped
@Transactional(Transactional.TxType.REQUIRED)
public class UserController implements Serializable {
    @Inject
    private UserService userService;
    private LazyUserDataModel users;
    private User selected;
    @PostConstruct
    public void init() {
        users = new LazyUserDataModel(userService);
    }
    public User getSelected() {
        return selected;
    }
    public void setSelected(User selected) {
        this.selected = selected;
    }
    public LazyUserDataModel getUsers() {
        return users;
    }
    public void setUsers(LazyUserDataModel users) {
        this.users = users;
    }
}

惰性数据模型

import java.util.List;
import java.util.Map;
import org.primefaces.model.LazyDataModel;
import org.primefaces.model.SortOrder;
public class LazyUserDataModel extends LazyDataModel<User> {
    private List<User> data;
    private final UserService userService;
    public LazyUserDataModel(UserService userService) {
        this.userService = userService;
    }
    @Override
    public User getRowData(String rowKey) {
        Long id = Long.valueOf(rowKey);
        for (User u : data) {
            if (u.getId().equals(id))
                return u;
        }
        return null;
    }
    @Override
    public Object getRowKey(User u) {
        return u.getId();
    }
    @Override
    public List<User> load(int first, int pageSize, String sortField, SortOrder sortOrder, Map<String,Object> filters) {
        UserFilterCorrector.correct(filters);
        UserFilter filter = new UserFilter(filters, first, pageSize);
        FilteredDataModel<User> userDataModel = userService.findFilteredList(filter);
        data = userDataModel.getData();
        this.setRowCount(userDataModel.getCount().intValue());
        return data;
    }
}

例外

11:07:46,348 SEVERE [javax.enterprise.resource.webcontainer.jsf.application] (default task-97) Error Rendering View[/user/List.xhtml]: java.lang.NullPointerException
 at javax.faces.component.StateHolderSaver.<init>(StateHolderSaver.java:96) [jboss-jsf-api_2.2_spec-2.2.8.jar:2.2.8]
 at javax.faces.component.UIComponentBase.saveAttachedState(UIComponentBase.java:1746) [jboss-jsf-api_2.2_spec-2.2.8.jar:2.2.8]
 at javax.faces.component.ComponentStateHelper.saveMap(ComponentStateHelper.java:378) [jboss-jsf-api_2.2_spec-2.2.8.jar:2.2.8]
 at javax.faces.component.ComponentStateHelper.saveState(ComponentStateHelper.java:256) [jboss-jsf-api_2.2_spec-2.2.8.jar:2.2.8]
 at javax.faces.component.UIComponentBase.saveState(UIComponentBase.java:1552) [jboss-jsf-api_2.2_spec-2.2.8.jar:2.2.8]
 at javax.faces.component.UIData.saveState(UIData.java:1780) [jboss-jsf-api_2.2_spec-2.2.8.jar:2.2.8]
 at org.primefaces.component.datatable.DataTable.saveState(DataTable.java:1520) [primefaces-5.1.jar:5.1]
 at com.sun.faces.application.view.FaceletPartialStateManagementStrategy$3.visit(FaceletPartialStateManagementStrategy.java:482) [jsf-impl-2.2.8-jbossorg-1.jar:]
 at com.sun.faces.component.visit.FullVisitContext.invokeVisitCallback(FullVisitContext.java:151) [jsf-impl-2.2.8-jbossorg-1.jar:]
 at org.primefaces.component.api.UIData.visitTree(UIData.java:692) [primefaces-5.1.jar:5.1]
 at javax.faces.component.UIComponent.visitTree(UIComponent.java:1700) [jboss-jsf-api_2.2_spec-2.2.8.jar:2.2.8]
 at javax.faces.component.UIComponent.visitTree(UIComponent.java:1700) [jboss-jsf-api_2.2_spec-2.2.8.jar:2.2.8]
 at javax.faces.component.UIForm.visitTree(UIForm.java:371) [jboss-jsf-api_2.2_spec-2.2.8.jar:2.2.8]
 at javax.faces.component.UIComponent.visitTree(UIComponent.java:1700) [jboss-jsf-api_2.2_spec-2.2.8.jar:2.2.8]
 at javax.faces.component.UIComponent.visitTree(UIComponent.java:1700) [jboss-jsf-api_2.2_spec-2.2.8.jar:2.2.8]
 at javax.faces.component.UIComponent.visitTree(UIComponent.java:1700) [jboss-jsf-api_2.2_spec-2.2.8.jar:2.2.8]
 at javax.faces.component.UIComponent.visitTree(UIComponent.java:1700) [jboss-jsf-api_2.2_spec-2.2.8.jar:2.2.8]
 at com.sun.faces.application.view.FaceletPartialStateManagementStrategy.saveView(FaceletPartialStateManagementStrategy.java:472) [jsf-impl-2.2.8-jbossorg-1.jar:]
 at com.sun.faces.application.StateManagerImpl.saveView(StateManagerImpl.java:89) [jsf-impl-2.2.8-jbossorg-1.jar:]
 at javax.faces.application.StateManager.getViewState(StateManager.java:593) [jboss-jsf-api_2.2_spec-2.2.8.jar:2.2.8]
 at com.sun.faces.context.PartialViewContextImpl.renderState(PartialViewContextImpl.java:483) [jsf-impl-2.2.8-jbossorg-1.jar:]
 at com.sun.faces.context.PartialViewContextImpl.processPartial(PartialViewContextImpl.java:325) [jsf-impl-2.2.8-jbossorg-1.jar:]
 at org.primefaces.context.PrimePartialViewContext.processPartial(PrimePartialViewContext.java:60) [primefaces-5.1.jar:5.1]
 at javax.faces.component.UIViewRoot.encodeChildren(UIViewRoot.java:1004) [jboss-jsf-api_2.2_spec-2.2.8.jar:2.2.8]
 at javax.faces.component.UIComponent.encodeAll(UIComponent.java:1856) [jboss-jsf-api_2.2_spec-2.2.8.jar:2.2.8]
 at com.sun.faces.application.view.FaceletViewHandlingStrategy.renderView(FaceletViewHandlingStrategy.java:430) [jsf-impl-2.2.8-jbossorg-1.jar:]
 at com.sun.faces.application.view.MultiViewHandler.renderView(MultiViewHandler.java:133) [jsf-impl-2.2.8-jbossorg-1.jar:]
 at javax.faces.application.ViewHandlerWrapper.renderView(ViewHandlerWrapper.java:337) [jboss-jsf-api_2.2_spec-2.2.8.jar:2.2.8]
 at javax.faces.application.ViewHandlerWrapper.renderView(ViewHandlerWrapper.java:337) [jboss-jsf-api_2.2_spec-2.2.8.jar:2.2.8]
 at com.sun.faces.lifecycle.RenderResponsePhase.execute(RenderResponsePhase.java:120) [jsf-impl-2.2.8-jbossorg-1.jar:]
 at com.sun.faces.lifecycle.Phase.doPhase(Phase.java:101) [jsf-impl-2.2.8-jbossorg-1.jar:]
 at com.sun.faces.lifecycle.LifecycleImpl.render(LifecycleImpl.java:219) [jsf-impl-2.2.8-jbossorg-1.jar:]
 at javax.faces.webapp.FacesServlet.service(FacesServlet.java:647) [jboss-jsf-api_2.2_spec-2.2.8.jar:2.2.8]
 at io.undertow.servlet.handlers.ServletHandler.handleRequest(ServletHandler.java:85) [undertow-servlet-1.1.0.Final.jar:1.1.0.Final]
 at io.undertow.servlet.handlers.security.ServletSecurityRoleHandler.handleRequest(ServletSecurityRoleHandler.java:61) [undertow-servlet-1.1.0.Final.jar:1.1.0.Final]
 at io.undertow.servlet.handlers.ServletDispatchingHandler.handleRequest(ServletDispatchingHandler.java:36) [undertow-servlet-1.1.0.Final.jar:1.1.0.Final]
 at org.wildfly.extension.undertow.security.SecurityContextAssociationHandler.handleRequest(SecurityContextAssociationHandler.java:78)
 at io.undertow.server.handlers.PredicateHandler.handleRequest(PredicateHandler.java:43) [undertow-core-1.1.0.Final.jar:1.1.0.Final]
 at io.undertow.servlet.handlers.security.SSLInformationAssociationHandler.handleRequest(SSLInformationAssociationHandler.java:131) [undertow-servlet-1.1.0.Final.jar:1.1.0.Final]
 at io.undertow.servlet.handlers.security.ServletAuthenticationCallHandler.handleRequest(ServletAuthenticationCallHandler.java:56) [undertow-servlet-1.1.0.Final.jar:1.1.0.Final]
 at io.undertow.server.handlers.PredicateHandler.handleRequest(PredicateHandler.java:43) [undertow-core-1.1.0.Final.jar:1.1.0.Final]
 at io.undertow.security.handlers.AbstractConfidentialityHandler.handleRequest(AbstractConfidentialityHandler.java:45) [undertow-core-1.1.0.Final.jar:1.1.0.Final]
 at io.undertow.servlet.handlers.security.ServletConfidentialityConstraintHandler.handleRequest(ServletConfidentialityConstraintHandler.java:63) [undertow-servlet-1.1.0.Final.jar:1.1.0.Final]
 at io.undertow.security.handlers.AuthenticationMechanismsHandler.handleRequest(AuthenticationMechanismsHandler.java:58) [undertow-core-1.1.0.Final.jar:1.1.0.Final]
 at io.undertow.servlet.handlers.security.CachedAuthenticatedSessionHandler.handleRequest(CachedAuthenticatedSessionHandler.java:70) [undertow-servlet-1.1.0.Final.jar:1.1.0.Final]
 at io.undertow.security.handlers.SecurityInitialHandler.handleRequest(SecurityInitialHandler.java:76) [undertow-core-1.1.0.Final.jar:1.1.0.Final]
 at io.undertow.server.handlers.PredicateHandler.handleRequest(PredicateHandler.java:43) [undertow-core-1.1.0.Final.jar:1.1.0.Final]
 at org.wildfly.extension.undertow.security.jacc.JACCContextIdHandler.handleRequest(JACCContextIdHandler.java:61)
 at io.undertow.server.handlers.PredicateHandler.handleRequest(PredicateHandler.java:43) [undertow-core-1.1.0.Final.jar:1.1.0.Final]
 at io.undertow.server.handlers.PredicateHandler.handleRequest(PredicateHandler.java:43) [undertow-core-1.1.0.Final.jar:1.1.0.Final]
 at io.undertow.servlet.handlers.ServletInitialHandler.handleFirstRequest(ServletInitialHandler.java:261) [undertow-servlet-1.1.0.Final.jar:1.1.0.Final]
 at io.undertow.servlet.handlers.ServletInitialHandler.dispatchRequest(ServletInitialHandler.java:247) [undertow-servlet-1.1.0.Final.jar:1.1.0.Final]
 at io.undertow.servlet.handlers.ServletInitialHandler.access$000(ServletInitialHandler.java:76) [undertow-servlet-1.1.0.Final.jar:1.1.0.Final]
 at io.undertow.servlet.handlers.ServletInitialHandler$1.handleRequest(ServletInitialHandler.java:166) [undertow-servlet-1.1.0.Final.jar:1.1.0.Final]
 at io.undertow.server.Connectors.executeRootHandler(Connectors.java:197) [undertow-core-1.1.0.Final.jar:1.1.0.Final]
 at io.undertow.server.HttpServerExchange$1.run(HttpServerExchange.java:759) [undertow-core-1.1.0.Final.jar:1.1.0.Final]
 at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1142) [rt.jar:1.8.0_25]
 at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:617) [rt.jar:1.8.0_25]
 at java.lang.Thread.run(Thread.java:745) [rt.jar:1.8.0_25]

我通过删除具有 null 的过滤器值并将其替换为空对象来解决我的问题。您可以将断点放在 jsf-api/2.2.8/jsf-api-2.2.8-sources.jar！/javax/faces/component/UIComponentBase.java：1746 中，并查看过滤器映射中的哪个值导致错误，然后将其替换为空对象或删除它。我希望这有所帮助。

这一定是 jsf api 实现中的一个错误。正如您在答案中所述@bcavlin源代码中没有足够的 null 检查来存储具有映射到 null 对象的任何键的 Map。我就此提交了JIRA问题，并在那里进行了更详细的描述，请参阅JAVASERVERFACES-4088（旧 java.net 问题）或JAVASERVERFACES-4092。

我这样做：

  1. 反编译 jboss-jsf-api_2.2_spec-2.2.11.jar
  2. 使用类 javax.faces.components.StateHolderSaver 创建一个新项目并粘贴反编译代码。
  3. 添加 jboss-jsf-api_2.2_spec-2.2.11.jar 作为库

  4. 尚格代码：

    public StateHolderSaver(FacesContext context, Object toSave){
   this.className=toSave.getClass().getName();

    自：

    public StateHolderSaver(FacesContext context, Object toSave){
   this.className=toSave!=null?toSave.getClass().getName():null;

  5. 清理和构建

  6. 替换 jboss-jsf-api_2.2_spec-2.2.11 中编译的 StateHolderSaver.jar
    7. 运行
  7. 服务器，它运行正常

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