javax.el.PropertyNotFoundException：在类型tn.ccs.evoice.entity.TicketSubject上找不到属性'displayOrder'

Question

1 /我最近在postgres数据库中添加了一个列（display_order）：

2 /我已更新其相关实体：

@Column(name = "display_order")
    private Integer displayOrder;

    public Integer getDisplayOrder() {
        return this.displayOrder;
    }
    public void setDisplayOrder(Integer displayOrder) {
        this.displayOrder = displayOrder;
    }

3 /我想使用以下代码在jsf页面中使用新列：

<div class="row">
       <p:outputLabel for="orderSubject" value="Ordre"  styleClass="col-md-3 
       control-label" />
          <div class="col-md-3">
            <div class="input-icon right">
            <p:spinner id="orderSubject" 
            value="#ticketSubjectController.selectedSubject.displayOrder}" />
          </div>
         </div>
 </div>

==＆GT;我收到了这个错误：

GRAVE: Servlet.service() for servlet [Faces Servlet] in context with path [/e-Voice] threw exception [/pages/secure/administration/subject/subject.xhtml @118,103 value="#{ticketSubjectController.selectedSubject.displayOrder}": Property 'displayOrder' not found on type tn.ccs.evoice.entity.TicketSubject] with root cause
    javax.el.PropertyNotFoundException: Property 'displayOrder' not found on type tn.ccs.evoice.entity.TicketSubject
        at javax.el.BeanELResolver$BeanProperties.get(BeanELResolver.java:290)
        at javax.el.BeanELResolver$BeanProperties.access$300(BeanELResolver.java:243)
        at javax.el.BeanELResolver.property(BeanELResolver.java:377)
        at javax.el.BeanELResolver.getValue(BeanELResolver.java:97)
        at com.sun.faces.el.DemuxCompositeELResolver._getValue(DemuxCompositeELResolver.java:176)
        at com.sun.faces.el.DemuxCompositeELResolver.getValue(DemuxCompositeELResolver.java:203)
        at org.apache.el.parser.AstValue.getValue(AstValue.java:184)
        at org.apache.el.ValueExpressionImpl.getValue(ValueExpressionImpl.java:184)
        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.UIOutput.getValue(UIOutput.java:174)
        at javax.faces.component.UIInput.getValue(UIInput.java:291)
        at org.primefaces.util.ComponentUtils.getValueToRender(ComponentUtils.java:94)
        at org.primefaces.util.ComponentUtils.getValueToRender(ComponentUtils.java:58)
        at org.primefaces.component.spinner.SpinnerRenderer.encodeInput(SpinnerRenderer.java:122)
        at org.primefaces.component.spinner.SpinnerRenderer.encodeMarkup(SpinnerRenderer.java:101)
        at org.primefaces.component.spinner.SpinnerRenderer.encodeEnd(SpinnerRenderer.java:66)
        at javax.faces.component.UIComponentBase.encodeEnd(UIComponentBase.java:919)
        at org.primefaces.renderkit.CoreRenderer.renderChild(CoreRenderer.java:89)
        at org.primefaces.renderkit.CoreRenderer.renderChildren(CoreRenderer.java:72)
        at org.primefaces.component.fieldset.FieldsetRenderer.encodeContent(FieldsetRenderer.java:94)
        at org.primefaces.component.fieldset.FieldsetRenderer.encodeMarkup(FieldsetRenderer.java:76)
        at org.primefaces.component.fieldset.FieldsetRenderer.encodeEnd(FieldsetRenderer.java:47)
        at javax.faces.component.UIComponentBase.encodeEnd(UIComponentBase.java:919)
        at javax.faces.component.UIComponent.encodeAll(UIComponent.java:1903)
        at javax.faces.component.UIComponent.encodeAll(UIComponent.java:1899)
        at org.primefaces.component.tabview.TabViewRenderer.encodeTabContent(TabViewRenderer.java:313)
        at org.primefaces.component.tabview.TabViewRenderer.encodeContents(TabViewRenderer.java:271)
        at org.primefaces.component.tabview.TabViewRenderer.encodeMarkup(TabViewRenderer.java:132)
        at org.primefaces.component.tabview.TabViewRenderer.encodeEnd(TabViewRenderer.java:71)  

我该怎么办？