Primefaces 数据表选定的行无法使用 viewscope 工作

我正在使用 JSF 2.0 和 Primefaces 3.4.2，我有一个使用延迟加载填充的数据表。

当我查看托管bean 的范围时，数据表 selectedRow 给出空指针异常。 如果我使用会话范围，那么我可以在托管bean中获取selectedRow。

我使用 CDI Spring 注释来指定范围。我用过this http://cagataycivici.wordpress.com/2010/02/17/port-jsf-2-0s-viewscope-to-spring-3-0/创建视图范围的方法。

Update 1

我注意到另一件事是当我分页到第二页然后返回第一页时使用视图范围，然后我可以获得 selectedRow。如果我选择一行而不分页，则会出现空指针异常。

JSF Page

<p:dataTable id="dataTable" var="req" lazy="true" value="#{emp.lazyModel}"
                paginator="true" rows="10" 
                             selection="#{emp.selectedRequest}"
                            selectionMode="single">                         
          <p:ajax event="rowSelect" listener="#{emp.onRowSelect}" />  

托管Bean

@Named("emp")
@Scope("view")
public class EmployeesManagedBean implements Serializable {

    @PostConstruct
    public void init() {
        initTable();
    }

    private void initTable() {
        lazyModel = new LazyRequestDataModel(requestList, requestService);
    }

    public LazyDataModel<Employee> getLazyModel() {
        return lazyModel;

    }

我在这一行收到空指针异常onRowSelect method

 Emp emp = (Emp) event.getObject()); 
 System.out.println(emp.getEmpNo() );

完整的错误堆栈跟踪

java.lang.NullPointerException
    at net.test.managed.bean.RequestManagedBean.onRowSelect(RequestManagedBean.java:134)
    at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
    at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:57)
    at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
    at java.lang.reflect.Method.invoke(Method.java:601)
    at com.sun.el.parser.AstValue.invoke(AstValue.java:187)
    at com.sun.el.MethodExpressionImpl.invoke(MethodExpressionImpl.java:297)
    at org.primefaces.component.behavior.ajax.AjaxBehaviorListenerImpl.processAjaxBehavior(AjaxBehaviorListenerImpl.java:52)
    at org.primefaces.event.SelectEvent.processListener(SelectEvent.java:40)
    at javax.faces.component.behavior.BehaviorBase.broadcast(BehaviorBase.java:106)
    at javax.faces.component.UIComponentBase.broadcast(UIComponentBase.java:760)
    at javax.faces.component.UIData.broadcast(UIData.java:1071)
    at javax.faces.component.UIData.broadcast(UIData.java:1093)
    at javax.faces.component.UIViewRoot.broadcastEvents(UIViewRoot.java:794)
    at javax.faces.component.UIViewRoot.processApplication(UIViewRoot.java:1259)
    at com.sun.faces.lifecycle.InvokeApplicationPhase.execute(InvokeApplicationPhase.java:81)
    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:593)
    at weblogic.servlet.internal.StubSecurityHelper$ServletServiceAction.run(StubSecurityHelper.java:227)
    at weblogic.servlet.internal.StubSecurityHelper.invokeServlet(StubSecurityHelper.java:125)
    at weblogic.servlet.internal.ServletStubImpl.execute(ServletStubImpl.java:301)
    at weblogic.servlet.internal.TailFilter.doFilter(TailFilter.java:26)
    at weblogic.servlet.internal.FilterChainImpl.doFilter(FilterChainImpl.java:56)
    at weblogic.servlet.internal.RequestEventsFilter.doFilter(RequestEventsFilter.java:27)
    at weblogic.servlet.internal.FilterChainImpl.doFilter(FilterChainImpl.java:56)
    at weblogic.servlet.internal.WebAppServletContext$ServletInvocationAction.wrapRun(WebAppServletContext.java:3730)
    at weblogic.servlet.internal.WebAppServletContext$ServletInvocationAction.run(WebAppServletContext.java:3696)
    at weblogic.security.acl.internal.AuthenticatedSubject.doAs(AuthenticatedSubject.java:321)
    at weblogic.security.service.SecurityManager.runAs(SecurityManager.java:120)
    at weblogic.servlet.internal.WebAppServletContext.securedExecute(WebAppServletContext.java:2273)
    at weblogic.servlet.internal.WebAppServletContext.execute(WebAppServletContext.java:2179)
    at weblogic.servlet.internal.ServletRequestImpl.run(ServletRequestImpl.java:1490)
    at weblogic.work.ExecuteThread.execute(ExecuteThread.java:256)
    at weblogic.work.ExecuteThread.run(ExecuteThread.java:221)

我已经设法通过使用解决了这个问题@ViewAccessScopedCDI 支持。在maven中添加依赖或者直接下载http://myfaces.apache.org/extensions/cdi/download.html http://myfaces.apache.org/extensions/cdi/download.html并将其放入类路径中。

<dependency>
    <groupId>org.apache.myfaces.extensions.cdi.core</groupId>
    <artifactId>myfaces-extcdi-core-api</artifactId>
    <version>1.0.5</version>
    <scope>compile</scope>
</dependency>

仍然存在一个小问题，即当第一次部署应用程序时，我仍然没有获得选定的行值，对于后续选择，我能够获得选定的行值。