两个 selectManyListbox 出错
我有两个相关的 selectManyListbox(第二个是根据第一个生成的),但是当 我运行应用程序时发生错误:
JSF:
<h:selectManyListbox value="#{TestAjax.selectedProjects}" id="project" size="3">
<f:selectItem itemLabel="-- Select Projects -- " itemValue="0"/>
<f:selectItems value="#{TestAjax.getMyListProject()}" />
<f:ajax event="change" render="status" />
</h:selectManyListbox>
<h:selectManyListbox value="#{TestAjax.selectedstatus}" id="status" size="3">
<f:selectItem itemLabel="-- Select status -- " itemValue="0"/>
<f:selectItems value="#{TestAjax.StepsByProject()}" />
</h:selectManyListbox>
错误:
java.lang.NullPointerException
at DAOKPI.TestAjax.FormattingVar(TestAjax.java:342)
at DAOKPI.TestAjax.StepsByProject(TestAjax.java:367)
at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:39)
at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:25)
at java.lang.reflect.Method.invoke(Method.java:597)
at javax.el.BeanELResolver.invokeMethod(BeanELResolver.java:737)
at javax.el.BeanELResolver.invoke(BeanELResolver.java:467)
at javax.el.CompositeELResolver.invoke(CompositeELResolver.java:254)
at com.sun.el.parser.AstValue.getValue(AstValue.java:111)
at com.sun.el.parser.AstValue.getValue(AstValue.java:163)
at com.sun.el.ValueExpressionImpl.getValue(ValueExpressionImpl.java:219)
at com.sun.faces.facelets.el.TagValueExpression.getValue(TagValueExpression.java:109)
at javax.faces.component.ComponentStateHelper.eval(ComponentStateHelper.java:194)
at javax.faces.component.ComponentStateHelper.eval(ComponentStateHelper.java:182)
at javax.faces.component.UISelectItems.getValue(UISelectItems.java:129)
at com.sun.faces.renderkit.SelectItemsIterator.initializeItems(SelectItemsIterator.java:202)
at com.sun.faces.renderkit.SelectItemsIterator.hasNext(SelectItemsIterator.java:135)
at com.sun.faces.renderkit.html_basic.MenuRenderer.renderOptions(MenuRenderer.java:762)
at com.sun.faces.renderkit.html_basic.MenuRenderer.renderSelect(MenuRenderer.java:844)
at com.sun.faces.renderkit.html_basic.MenuRenderer.encodeEnd(MenuRenderer.java:298)
at javax.faces.component.UIComponentBase.encodeEnd(UIComponentBase.java:875)
at com.sun.faces.renderkit.html_basic.HtmlBasicRenderer.encodeRecursive(HtmlBasicRenderer.java :312)
at com.sun.faces.renderkit.html_basic.GridRenderer.renderRow(GridRenderer.java:185)
at com.sun.faces.renderkit.html_basic.GridRenderer.encodeChildren(GridRenderer.java:129)
at javax.faces.component.UIComponentBase.encodeChildren(UIComponentBase.java:845)
at org.primefaces.renderkit.CoreRenderer.renderChild(CoreRenderer.java:55)
at org.primefaces.renderkit.CoreRenderer.renderChildren(CoreRenderer.java:43)
at org.primefaces.component.panel.PanelRenderer.encodeContent(PanelRenderer.java:229)
at org.primefaces.component.panel.PanelRenderer.encodeMarkup(PanelRenderer.java:152)
at org.primefaces.component.panel.PanelRenderer.encodeEnd(PanelRenderer.java:75)
at javax.faces.component.UIComponentBase.encodeEnd(UIComponentBase.java:875)
at javax.faces.component.UIComponent.encodeAll(UIComponent.java:1763)
at javax.faces.render.Renderer.encodeChildren(Renderer.java:168)
at javax.faces.component.UIComponentBase.encodeChildren(UIComponentBase.java:845)
at javax.faces.component.UIComponent.encodeAll(UIComponent.java:1756)
at javax.faces.component.UIComponent.encodeAll(UIComponent.java:1759)
at javax.faces.component.UIComponent.encodeAll(UIComponent.java:1759)
at com.sun.faces.application.view.FaceletViewHandlingStrategy.renderView(FaceletViewHandlingSt rategy.java:401)
at com.sun.faces.application.view.MultiViewHandler.renderView(MultiViewHandler.java:131)
at com.sun.faces.lifecycle.RenderResponsePhase.execute(RenderResponsePhase.java:121)
at com.sun.faces.lifecycle.Phase.doPhase(Phase.java:101)
at com.sun.faces.lifecycle.LifecycleImpl.render(LifecycleImpl.java:139)
I have two selectManyListbox related(the second is generated accordind the first) ,but when
I run the application an error occure:
JSF:
<h:selectManyListbox value="#{TestAjax.selectedProjects}" id="project" size="3">
<f:selectItem itemLabel="-- Select Projects -- " itemValue="0"/>
<f:selectItems value="#{TestAjax.getMyListProject()}" />
<f:ajax event="change" render="status" />
</h:selectManyListbox>
<h:selectManyListbox value="#{TestAjax.selectedstatus}" id="status" size="3">
<f:selectItem itemLabel="-- Select status -- " itemValue="0"/>
<f:selectItems value="#{TestAjax.StepsByProject()}" />
</h:selectManyListbox>
The error:
java.lang.NullPointerException
at DAOKPI.TestAjax.FormattingVar(TestAjax.java:342)
at DAOKPI.TestAjax.StepsByProject(TestAjax.java:367)
at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:39)
at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:25)
at java.lang.reflect.Method.invoke(Method.java:597)
at javax.el.BeanELResolver.invokeMethod(BeanELResolver.java:737)
at javax.el.BeanELResolver.invoke(BeanELResolver.java:467)
at javax.el.CompositeELResolver.invoke(CompositeELResolver.java:254)
at com.sun.el.parser.AstValue.getValue(AstValue.java:111)
at com.sun.el.parser.AstValue.getValue(AstValue.java:163)
at com.sun.el.ValueExpressionImpl.getValue(ValueExpressionImpl.java:219)
at com.sun.faces.facelets.el.TagValueExpression.getValue(TagValueExpression.java:109)
at javax.faces.component.ComponentStateHelper.eval(ComponentStateHelper.java:194)
at javax.faces.component.ComponentStateHelper.eval(ComponentStateHelper.java:182)
at javax.faces.component.UISelectItems.getValue(UISelectItems.java:129)
at com.sun.faces.renderkit.SelectItemsIterator.initializeItems(SelectItemsIterator.java:202)
at com.sun.faces.renderkit.SelectItemsIterator.hasNext(SelectItemsIterator.java:135)
at com.sun.faces.renderkit.html_basic.MenuRenderer.renderOptions(MenuRenderer.java:762)
at com.sun.faces.renderkit.html_basic.MenuRenderer.renderSelect(MenuRenderer.java:844)
at com.sun.faces.renderkit.html_basic.MenuRenderer.encodeEnd(MenuRenderer.java:298)
at javax.faces.component.UIComponentBase.encodeEnd(UIComponentBase.java:875)
at com.sun.faces.renderkit.html_basic.HtmlBasicRenderer.encodeRecursive(HtmlBasicRenderer.java :312)
at com.sun.faces.renderkit.html_basic.GridRenderer.renderRow(GridRenderer.java:185)
at com.sun.faces.renderkit.html_basic.GridRenderer.encodeChildren(GridRenderer.java:129)
at javax.faces.component.UIComponentBase.encodeChildren(UIComponentBase.java:845)
at org.primefaces.renderkit.CoreRenderer.renderChild(CoreRenderer.java:55)
at org.primefaces.renderkit.CoreRenderer.renderChildren(CoreRenderer.java:43)
at org.primefaces.component.panel.PanelRenderer.encodeContent(PanelRenderer.java:229)
at org.primefaces.component.panel.PanelRenderer.encodeMarkup(PanelRenderer.java:152)
at org.primefaces.component.panel.PanelRenderer.encodeEnd(PanelRenderer.java:75)
at javax.faces.component.UIComponentBase.encodeEnd(UIComponentBase.java:875)
at javax.faces.component.UIComponent.encodeAll(UIComponent.java:1763)
at javax.faces.render.Renderer.encodeChildren(Renderer.java:168)
at javax.faces.component.UIComponentBase.encodeChildren(UIComponentBase.java:845)
at javax.faces.component.UIComponent.encodeAll(UIComponent.java:1756)
at javax.faces.component.UIComponent.encodeAll(UIComponent.java:1759)
at javax.faces.component.UIComponent.encodeAll(UIComponent.java:1759)
at com.sun.faces.application.view.FaceletViewHandlingStrategy.renderView(FaceletViewHandlingSt rategy.java:401)
at com.sun.faces.application.view.MultiViewHandler.renderView(MultiViewHandler.java:131)
at com.sun.faces.lifecycle.RenderResponsePhase.execute(RenderResponsePhase.java:121)
at com.sun.faces.lifecycle.Phase.doPhase(Phase.java:101)
at com.sun.faces.lifecycle.LifecycleImpl.render(LifecycleImpl.java:139)
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这告诉你所有你需要知道的事情。您的类 TestAjax 中发生空指针异常,方法为 FormattingVar(),行号为 342。
从您的 JSF 页面中,错误发生在第二个 selectManyListbox 中,如堆栈跟踪中的 StepsByProject() 所示
This tells you all you need to know. A null pointer exception occured in your class TestAjax, the method was FormattingVar() and the line number is 342.
From your JSF page, the error occured in the 2nd selectManyListbox, as seen by the StepsByProject() in the stacktrace as well