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我是 primefaces 3.2 的新手。我需要从 SelectOneMenu 中的数据库中获取部门的所有名称，但我没有！

<h:outputText value="Département : " />  
<h:selectOneMenu value="#{departementBean.departement}" converter="#{departementConverter}">
    <f:selectItem itemLabel="Select One" itemValue="" noSelectionOption="true"/>
    <f:selectItems var="dep" value="#{departementBean.list}" itemLabel="libelleDepartement" itemValue="#{departementBean.departement}" />
</h:selectOneMenu>

这是来自这个 Tuto 的 DepartementConverter如何从数据库中填充 h:selectOneMenu 的选项？ 

@ManagedBean(name = "departementConverter")
@RequestScoped
public class DepartementConverter implements Converter {

    @ManagedProperty(value = "#{departementService}")
    private DepartementService departementService;

    @Override
    public Object getAsObject(FacesContext context, UIComponent component, String value) {

        Long id = Long.valueOf(value);

        try {
            return departementService.find(String.valueOf(id));
        } catch (Exception e) {
            throw new ConverterException(new FacesMessage(String.format("Cannot convert %s to Departement", value)), e);
        }
    }

    @Override
    public String getAsString(FacesContext context, UIComponent component, Object value) {
        Departement departement = (Departement) value;
        return String.valueOf(departement.getIdDepartement());
    }

    public DepartementService getDepartementService() {
        return departementService;
    }

    public void setDepartementService(DepartementService departementService) {
        this.departementService = departementService;
    }
}

DAOImpl的查找方法如下：

public Object find(String id) {
    return this.getHibernateTemplate().find(id);
}

但是当我运行项目时，我有这个错误：

    INFO: Exception when handling error trying to reset the response.
java.lang.ClassCastException: java.lang.String
    at com.majustic.majemploi.converter.DepartementConverter.getAsString(DepartementConverter.java:43)
    at com.sun.faces.renderkit.html_basic.HtmlBasicRenderer.getFormattedValue(HtmlBasicRenderer.java:519)
    at com.sun.faces.renderkit.html_basic.MenuRenderer.renderOption(MenuRenderer.java:534)
    at com.sun.faces.renderkit.html_basic.MenuRenderer.renderOptions(MenuRenderer.java:792)
    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:57)
    at org.primefaces.renderkit.CoreRenderer.renderChildren(CoreRenderer.java:45)
    at org.primefaces.component.panel.PanelRenderer.encodeContent(PanelRenderer.java:185)
    at org.primefaces.component.panel.PanelRenderer.encodeMarkup(PanelRenderer.java:108)
    at org.primefaces.component.panel.PanelRenderer.encodeEnd(PanelRenderer.java:55)
    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 javax.faces.component.UIComponent.encodeAll(UIComponent.java:1779)
    at javax.faces.component.UIComponent.encodeAll(UIComponent.java:1782)
    at org.primefaces.component.accordionpanel.AccordionPanelRenderer.encodeTab(AccordionPanelRenderer.java:218)
    at org.primefaces.component.accordionpanel.AccordionPanelRenderer.encodeTabs(AccordionPanelRenderer.java:147)
    at org.primefaces.component.accordionpanel.AccordionPanelRenderer.encodeMarkup(AccordionPanelRenderer.java:91)
    at org.primefaces.component.accordionpanel.AccordionPanelRenderer.encodeEnd(AccordionPanelRenderer.java:71)
    at javax.faces.component.UIComponentBase.encodeEnd(UIComponentBase.java:875)
    at javax.faces.component.UIComponent.encodeAll(UIComponent.java:1786)
    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:1779)
    at javax.faces.component.UIComponent.encodeAll(UIComponent.java:1782)
    at javax.faces.component.UIComponent.encodeAll(UIComponent.java:1782)
    at com.sun.faces.application.view.FaceletViewHandlingStrategy.renderView(FaceletViewHandlingStrategy.java:402)
    at com.sun.faces.application.view.MultiViewHandler.renderView(MultiViewHandler.java:128)
    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)
    at javax.faces.webapp.FacesServlet.service(FacesServlet.java:594)
    at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:305)
    at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:210)
    at org.springframework.security.web.FilterChainProxy$VirtualFilterChain.doFilter(FilterChainProxy.java:368)
    at org.springframework.security.web.access.intercept.FilterSecurityInterceptor.invoke(FilterSecurityInterceptor.java:109)
    at org.springframework.security.web.access.intercept.FilterSecurityInterceptor.doFilter(FilterSecurityInterceptor.java:84)
    at org.springframework.security.web.FilterChainProxy$VirtualFilterChain.doFilter(FilterChainProxy.java:380)
    at org.springframework.security.web.access.ExceptionTranslationFilter.doFilter(ExceptionTranslationFilter.java:97)
    at org.springframework.security.web.FilterChainProxy$VirtualFilterChain.doFilter(FilterChainProxy.java:380)
    at org.springframework.security.web.session.SessionManagementFilter.doFilter(SessionManagementFilter.java:101)
    at org.springframework.security.web.FilterChainProxy$VirtualFilterChain.doFilter(FilterChainProxy.java:380)
    at org.springframework.security.web.authentication.AnonymousAuthenticationFilter.doFilter(AnonymousAuthenticationFilter.java:79)
    at org.springframework.security.web.FilterChainProxy$VirtualFilterChain.doFilter(FilterChainProxy.java:380)
    at org.springframework.security.web.authentication.rememberme.RememberMeAuthenticationFilter.doFilter(RememberMeAuthenticationFilter.java:119)
    at org.springframework.security.web.FilterChainProxy$VirtualFilterChain.doFilter(FilterChainProxy.java:380)
    at org.springframework.security.web.servletapi.SecurityContextHolderAwareRequestFilter.doFilter(SecurityContextHolderAwareRequestFilter.java:55)
    at org.springframework.security.web.FilterChainProxy$VirtualFilterChain.doFilter(FilterChainProxy.java:380)
    at org.springframework.security.web.savedrequest.RequestCacheAwareFilter.doFilter(RequestCacheAwareFilter.java:36)
    at org.springframework.security.web.FilterChainProxy$VirtualFilterChain.doFilter(FilterChainProxy.java:380)
    at org.springframework.security.web.authentication.www.BasicAuthenticationFilter.doFilter(BasicAuthenticationFilter.java:178)
    at org.springframework.security.web.FilterChainProxy$VirtualFilterChain.doFilter(FilterChainProxy.java:380)
    at org.springframework.security.web.authentication.AbstractAuthenticationProcessingFilter.doFilter(AbstractAuthenticationProcessingFilter.java:189)
    at org.springframework.security.web.FilterChainProxy$VirtualFilterChain.doFilter(FilterChainProxy.java:380)
    at org.springframework.security.web.authentication.logout.LogoutFilter.doFilter(LogoutFilter.java:106)
    at org.springframework.security.web.FilterChainProxy$VirtualFilterChain.doFilter(FilterChainProxy.java:380)
    at org.springframework.security.web.context.SecurityContextPersistenceFilter.doFilter(SecurityContextPersistenceFilter.java:79)
    at org.springframework.security.web.FilterChainProxy$VirtualFilterChain.doFilter(FilterChainProxy.java:380)
    at org.springframework.security.web.FilterChainProxy.doFilter(FilterChainProxy.java:170)
    at org.springframework.web.filter.DelegatingFilterProxy.invokeDelegate(DelegatingFilterProxy.java:238)
    at org.springframework.web.filter.DelegatingFilterProxy.doFilter(DelegatingFilterProxy.java:168)
    at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:243)
    at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:210)
    at org.apache.catalina.core.StandardWrapperValve.invoke(StandardWrapperValve.java:225)
    at org.apache.catalina.core.StandardContextValve.invoke(StandardContextValve.java:170)
    at org.apache.catalina.authenticator.AuthenticatorBase.invoke(AuthenticatorBase.java:473)
    at org.apache.catalina.core.StandardHostValve.invoke(StandardHostValve.java:168)
    at org.apache.catalina.valves.ErrorReportValve.invoke(ErrorReportValve.java:100)
    at org.apache.catalina.valves.AccessLogValve.invoke(AccessLogValve.java:928)
    at org.apache.catalina.core.StandardEngineValve.invoke(StandardEngineValve.java:120)
    at org.apache.catalina.connector.CoyoteAdapter.service(CoyoteAdapter.java:407)
    at org.apache.coyote.http11.AbstractHttp11Processor.process(AbstractHttp11Processor.java:999)
    at org.apache.coyote.AbstractProtocol$AbstractConnectionHandler.process(AbstractProtocol.java:565)
    at org.apache.tomcat.util.net.JIoEndpoint$SocketProcessor.run(JIoEndpoint.java:309)
    at java.util.concurrent.ThreadPoolExecutor$Worker.runTask(ThreadPoolExecutor.java:886)
    at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:909)
    at java.lang.Thread.run(Thread.java:662)

错误在这个 ligne ：

部门部门=（部门）值；

拜托，我无法解决这个错误。请任何帮助！

4

2 回答 2

3

我认为问题在于 noSelectionOption。

您应该从此选项中删除您的 itemValue 属性：

<f:selectItem itemLabel="Select one" 
        noSelectionOption="true"/>

或者itemValue=""在您的转换器中处理外壳。

于 2012-04-27T11:34:36.497 回答
3

这是您可以使用的通用 GetAsString，如果您的所有实体都使用 getId() 方法实现接口（坦率地说，如果您的所有实体都有一个 Id 作为主键，这是一个好主意）

@Override
public String getAsString(FacesContext facesContext, UIComponent component, Object object) {
    if (object == null) {
        return null;
    }
    if (object instanceof AbstractEntity) {
        AbstractEntity e = (AbstractEntity) object;
        return "" + e.getId();
    }
    else
        throw new IllegalArgumentException("object " + object + " is of type " + object.getClass().getName() + "; expected AbstractEntity";
}
于 2012-04-27T11:45:27.500 回答