通过 p:remoteCommand 向 Spring bean 提供参数

Question

以下 XHTML 在请求作用域 Bean 到 <p:remoteCommand> <p:selectOneMenu> 中设置一个选定的值。

<h:form id="languageForm" prependId="true">
    <pe:blockUI target=":body" widgetVar="blockBodyUIWidget">
        <h:panelGrid columns="2">
            <h:graphicImage library="default" name="images/ajax-loader1.gif" class="block-ui-image"/>
            <h:outputText value="#{messages['blockui.panel.message']}" class="block-ui-text"/>
        </h:panelGrid>
    </pe:blockUI>
    <p:selectOneMenu id="languages" value="#{localeBean.language}" onchange="changeLanguage([{name:'language', value:this.value}]);">
        <f:selectItem itemValue="en" itemLabel="#{messages['languages.english']}" />
        <f:selectItem itemValue="hi" itemLabel="#{messages['languages.hindi']}" />
    </p:selectOneMenu>
    <p:remoteCommand name="changeLanguage" process="@this" update="@none" onstart="PF('blockBodyUIWidget').block();" oncomplete="PF('blockBodyUIWidget').unblock();" action="#{intermediateLocaleBean.localeAction}"/>
</h:form>

相应的 JSF 管理的 Bean：

@ManagedBean
@RequestScoped
public final class IntermediateLocaleBean
{
    @ManagedProperty("#{param.language}")
    private String language;
    @ManagedProperty("#{localeBean}")
    private LocaleBean localeBean;  //Injecting another session scoped bean here.
    public IntermediateLocaleBean() {}
    public void setLanguage(String language) {
        this.language = language;
    }
    public void setLocaleBean(LocaleBean localeBean) {
        this.localeBean = localeBean;
    }
    public String localeAction()
    {
        localeBean.setLocale(language.equals("hi")?new Locale(language, "IN"):new Locale(language));
        return FacesContext.getCurrentInstance().getViewRoot().getViewId() + "?faces-redirect=true";
    }
}

language 属性初始化为 <p:selectOneMenu> 中的选定语言。这一切都是完成的，因为它是一个 JSF 管理的 Bean。

---

如果，豆子由春天维护如下呢？

@Controller
@Scope("request")
public final class IntermediateLocaleBean
{
    //Do something to initialize the property - language.
    //@ManagedProperty would not work as this bean is managed by Spring.
    //It is not initialized to the selected language in <p:selectOneMenu>.
    //It is null.
    private String language;
    //The session scoped bean is injected using the @Autowired annotation as follows.
    @Autowired
    private final transient LocaleBean localeBean=null;
    public IntermediateLocaleBean() {}
    public void setLanguage(String language) {
        this.language = language;
    }
    public String localeAction()
    {
        localeBean.setLocale(language.equals("hi")?new Locale(language, "IN"):new Locale(language));
        return FacesContext.getCurrentInstance().getViewRoot().getViewId() + "?faces-redirect=true";
    }
}

如何将 language 属性初始化为此 Bean 中<p:selectOneMenu>的选定语言？

Answer 1

传统上，language - 请求参数的参数值可以使用

FacesContext context = FacesContext.getCurrentInstance();
String language = context.getExternalContext().getRequestParameterMap().get("language");

像下面这样，

@Controller
@Scope("request")
public final class IntermediateLocaleBean
{
    @Autowired
    private final transient LocaleBean localeBean=null;
    public IntermediateLocaleBean() {}
    public void setLanguage(String language) {
        this.language = language;
    }
    public String localeAction()
    {
        String language = FacesContext.getCurrentInstance().getExternalContext().getRequestParameterMap().get("language");
        localeBean.setLocale(language.equals("hi")?new Locale(language, "IN"):new Locale(language));
        return FacesContext.getCurrentInstance().getViewRoot().getViewId() + "?faces-redirect=true";
    }
}

但我个人不喜欢使用 FacesContext 公开整个请求，除非绝对必要。

---

Spring

中有一个org.springframework.beans.factory.annotation.Value注解，可以与 Spring 表达式语言一起使用，获取请求参数，如下所示。

@Controller
@Scope("request")
public final class IntermediateLocaleBean
{
    @Value("#{request.getParameter('language')}") //Exposing the value of language.
    private String language;
    @Autowired
    private final transient LocaleBean localeBean=null;
    public IntermediateLocaleBean() {}
    public void setLanguage(String language) {
        this.language = language;
    }
    public String localeAction()
    {
        localeBean.setLocale(language.equals("hi")?new Locale(language, "IN"):new Locale(language));
        return FacesContext.getCurrentInstance().getViewRoot().getViewId() + "?faces-redirect=true";
    }
}

<p:remoteCommand> 作为请求参数提供的 language 值现在可以使用@Value注释在此 bean 中使用（在我的情况下不需要用于language的 getter 方法）。

_{如果有其他可用，请建议或添加其他答案！}