不能显示所有JDBC列的数据，为什么？（类“C.C.C.SomeClass.class”没有属性“Some property”）

Question

我有一个包含两列的实体类，restaurantname和seats。

我可以从restaurantname列获取数据并将其显示在应用程序（网站）上，但不能从seats列获取数据。当我试图显示座位数据时，网站会以这样的方式运行，即带有数据的datatable消失了，同时网站也消失了一半。

下面是DataTable的代码：

<p:dataTable var="restaurants" value="#{restaurantBB.allRestaurants}">
                        <p:column headerText="Restaurants">
                            <p:graphicImage value="/resources/images/mcdonalds.png"/>
                            <h:outputText value="#{restaurants.name}" />
                        </p:column>
                        <p:column headerText="Seats">
                             <h:outputText value="#{restaurants.seats}" />
                        </p:column>
                    </p:dataTable>

@Entity
@Table(name="RESTAURANTS")
public class Restaurants extends AbstractEntity {

    @Column(nullable = false)
    private String name;
    @Column(nullable = false)
    private String seats;

    public Restaurants() {
        ;
    }

    public Restaurants(String name) {
        this.name = name;
        seats = "23";
    }

    public Restaurants(Long id, String name) {
        super(id);
        this.name = name;
        seats = "23";
    }

    @Override
    public String toString() {
        return "Restaurants{" + "id=" + getId() + ", name=" + getName() + '}';
    }

    /**
     * @return the name
     */
    public String getName() {
        return name;
    }

    /**
     * @param name the name to set
     */
    public void setName(String name) {
        this.name = name;
    }

    /**
     * @return the seats
     */
    public String getSeats() {
        return seats;
    }

为了测试的目的，我将座椅变量设置为“23”。如果你需要其他代码，请告诉我。

Edit：NetBeans抛出此错误：

The class 'c.c.c.c.c.Restaurants' does not have the property 'seats

我不知道我在这里做什么？有人吗？

编辑2：

FATAL:   JSF1073: javax.el.PropertyNotFoundException caught during processing of RENDER_RESPONSE 6 : UIComponent-ClientId=, Message=/index.xhtml @150,74 value="#{restaurants.seats}": The class 'c.c.c.c.c.Restaurants' does not have the property 'seats'.
FATAL:   /index.xhtml @150,74 value="#{restaurants.seats}": The class 'c.c.c.c.c.Restaurants' does not have the property 'seats'.
javax.el.PropertyNotFoundException: /index.xhtml @150,74 value="#{restaurants.seats}": The class 'c.c.c.c.c.Restaurants' does not have the property 'seats'.
    at com.sun.faces.facelets.el.TagValueExpression.getValue(TagValueExpression.java:111)
    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 com.sun.faces.renderkit.html_basic.HtmlBasicInputRenderer.getValue(HtmlBasicInputRenderer.java:205)
    at com.sun.faces.renderkit.html_basic.HtmlBasicRenderer.getCurrentValue(HtmlBasicRenderer.java:355)
    at com.sun.faces.renderkit.html_basic.HtmlBasicRenderer.encodeEnd(HtmlBasicRenderer.java:164)
    at javax.faces.component.UIComponentBase.encodeEnd(UIComponentBase.java:919)
    at javax.faces.component.UIComponent.encodeAll(UIComponent.java:1863)
    at org.primefaces.component.column.Column.renderChildren(Column.java:304)
    at org.primefaces.component.datatable.DataTableRenderer.encodeCell(DataTableRenderer.java:963)
    at org.primefaces.component.datatable.DataTableRenderer.encodeRow(DataTableRenderer.java:919)
    at org.primefaces.component.datatable.DataTableRenderer.encodeRows(DataTableRenderer.java:830)
    at org.primefaces.component.datatable.DataTableRenderer.encodeTbody(DataTableRenderer.java:777)
    at org.primefaces.component.datatable.DataTableRenderer.encodeTbody(DataTableRenderer.java:740)
    at org.primefaces.component.datatable.DataTableRenderer.encodeRegularTable(DataTableRenderer.java:264)
    at org.primefaces.component.datatable.DataTableRenderer.encodeMarkup(DataTableRenderer.java:226)
    at org.primefaces.component.datatable.DataTableRenderer.encodeEnd(DataTableRenderer.java:85)
    at javax.faces.component.UIComponentBase.encodeEnd(UIComponentBase.java:919)
    at javax.faces.component.UIComponent.encodeAll(UIComponent.java:1863)
    at javax.faces.component.UIComponent.encodeAll(UIComponent.java:1859)
    at javax.faces.component.UIComponent.encodeAll(UIComponent.java:1859)
    at com.sun.faces.application.view.FaceletViewHandlingStrategy.renderView(FaceletViewHandlingStrategy.java:456)
    at com.sun.faces.application.view.MultiViewHandler.renderView(MultiViewHandler.java:133)
    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 javax.faces.webapp.FacesServlet.service(FacesServlet.java:647)
    at org.apache.catalina.core.StandardWrapper.service(StandardWrapper.java:1682)
    at org.apache.catalina.core.StandardWrapperValve.invoke(StandardWrapperValve.java:318)
    at org.apache.catalina.core.StandardContextValve.invoke(StandardContextValve.java:160)
    at org.apache.catalina.core.StandardPipeline.doInvoke(StandardPipeline.java:734)
    at org.apache.catalina.core.StandardPipeline.invoke(StandardPipeline.java:673)
    at com.sun.enterprise.web.WebPipeline.invoke(WebPipeline.java:99)
    at org.apache.catalina.core.StandardHostValve.invoke(StandardHostValve.java:174)
    at org.apache.catalina.connector.CoyoteAdapter.doService(CoyoteAdapter.java:415)
    at org.apache.catalina.connector.CoyoteAdapter.service(CoyoteAdapter.java:282)
    at com.sun.enterprise.v3.services.impl.ContainerMapper$HttpHandlerCallable.call(ContainerMapper.java:459)
    at com.sun.enterprise.v3.services.impl.ContainerMapper.service(ContainerMapper.java:167)
    at org.glassfish.grizzly.http.server.HttpHandler.runService(HttpHandler.java:201)
    at org.glassfish.grizzly.http.server.HttpHandler.doHandle(HttpHandler.java:175)
    at org.glassfish.grizzly.http.server.HttpServerFilter.handleRead(HttpServerFilter.java:235)
    at org.glassfish.grizzly.filterchain.ExecutorResolver$9.execute(ExecutorResolver.java:119)
    at org.glassfish.grizzly.filterchain.DefaultFilterChain.executeFilter(DefaultFilterChain.java:284)
    at org.glassfish.grizzly.filterchain.DefaultFilterChain.executeChainPart(DefaultFilterChain.java:201)
    at org.glassfish.grizzly.filterchain.DefaultFilterChain.execute(DefaultFilterChain.java:133)
    at org.glassfish.grizzly.filterchain.DefaultFilterChain.process(DefaultFilterChain.java:112)
    at org.glassfish.grizzly.ProcessorExecutor.execute(ProcessorExecutor.java:77)
    at org.glassfish.grizzly.nio.transport.TCPNIOTransport.fireIOEvent(TCPNIOTransport.java:561)
    at org.glassfish.grizzly.strategies.AbstractIOStrategy.fireIOEvent(AbstractIOStrategy.java:112)
    at org.glassfish.grizzly.strategies.WorkerThreadIOStrategy.run0(WorkerThreadIOStrategy.java:117)
    at org.glassfish.grizzly.strategies.WorkerThreadIOStrategy.access$100(WorkerThreadIOStrategy.java:56)
    at org.glassfish.grizzly.strategies.WorkerThreadIOStrategy$WorkerThreadRunnable.run(WorkerThreadIOStrategy.java:137)
    at org.glassfish.grizzly.threadpool.AbstractThreadPool$Worker.doWork(AbstractThreadPool.java:565)
    at org.glassfish.grizzly.threadpool.AbstractThreadPool$Worker.run(AbstractThreadPool.java:545)
    at java.lang.Thread.run(Thread.java:745)
Caused by: javax.el.PropertyNotFoundException: The class 'c.c.c.c.c.Restaurants' does not have the property 'seats'.
    at javax.el.BeanELResolver.getBeanProperty(BeanELResolver.java:731)
    at javax.el.BeanELResolver.getValue(BeanELResolver.java:351)
    at com.sun.faces.el.DemuxCompositeELResolver._getValue(DemuxCompositeELResolver.java:176)
    at com.sun.faces.el.DemuxCompositeELResolver.getValue(DemuxCompositeELResolver.java:203)
    at com.sun.el.parser.AstValue.getValue(AstValue.java:140)
    at com.sun.el.parser.AstValue.getValue(AstValue.java:204)
    at com.sun.el.ValueExpressionImpl.getValue(ValueExpressionImpl.java:226)
    at org.jboss.weld.el.WeldValueExpression.getValue(WeldValueExpression.java:50)
    at com.sun.faces.facelets.el.TagValueExpression.getValue(TagValueExpression.java:109)
    ... 56 more

Answer 1

看起来列seats不在数据库表restaurants中。顺便说一句：以复数形式命名实体实际上是一种糟糕的做法，并不是错误的，但只是不是常见的设计。用单数命名实体，这样就可以区别于列表（“restaurants”）和单个实体（“restaurants”）。

要解决问题，只需将该列手动添加到数据库中，或者让eclipseLink处理模式和表的创建。只需将以下属性添加到persistence.xml中：

<property name="eclipselink.ddl-generation" value="create-or-extend-tables"/>

现在，在部署时，每当实体发生变化时，eclipseLink将创建新的表、联接表和列。这是自动创建数据库的一种非常简单和方便的方法。