我可以创建带注释的Faces应用程序侦听器类吗？

Question

我想创建一个带有注释的Faces应用程序侦听器，我有以下类：

package com.chhibi.listener;

    import javax.faces.application.Application;
    import javax.faces.event.AbortProcessingException;
    import javax.faces.event.PostConstructApplicationEvent;
    import javax.faces.event.PreDestroyApplicationEvent;
    import javax.faces.event.SystemEvent;
    import javax.faces.event.SystemEventListener;

    public class FacesAppListener implements SystemEventListener {

        @Override
        public void processEvent(SystemEvent event) throws AbortProcessingException {

            if (event instanceof PostConstructApplicationEvent) {
                // other code here
            }

            if (event instanceof PreDestroyApplicationEvent) {
                //other code here
            }

        }

        @Override
        public boolean isListenerForSource(Object source) {
            // only for Application
            return (source instanceof Application);

        }
    }

我想用注解替换faces-config.xml的配置，该怎么办？

<!-- Application is started -->
        <system-event-listener>
            <system-event-listener-class>
                com.chhibi.listenner.FacesAppListener
            </system-event-listener-class>
            <system-event-class>
                javax.faces.event.PostConstructApplicationEvent
            </system-event-class>                       
        </system-event-listener>     

        <!-- Before Application is shut down -->
        <system-event-listener>
            <system-event-listener-class>
                com.chhibi.listenner.FacesAppListener
            </system-event-listener-class>
            <system-event-class>
                javax.faces.event.PreDestroyApplicationEvent
            </system-event-class>                       
        </system-event-listener> 

Answer 1

对此没有注解。更重要的是，你本质上是在使用错误的工具。只需使用eagerly initialized application scoped managed bean即可。

@ManagedBean(eager=true)
@ApplicationScoped
public class MyApplicationBean {

    @PostConstruct
    public void onPostConstruct() {
        // Put code here which should be executed on application's startup.
    }

    @PreDestroy
    public void onPreDestroy() {
        // Put code here which should be executed on application's shutdown.
    }

}

就这样。不需要额外的XML冗长。

或者，如果您对FacesContext提供的JSF工件不感兴趣，那么您也可以使用标准的servlet上下文侦听器：

@WebListener
public class MyApplicationListener implements ServletContextListener {

    @Override
    public void contextInitialized(ServletContextEvent event) {
        // Put code here which should be executed on application's startup.
    }

    @Override
    public void contextDestroyed(ServletContextEvent event) {
        // Put code here which should be executed on application's shutdown.
    }

} 

同样在这里，不需要额外的XML。

SystemEventListener旨在连接到UIComponent或Renderer，而不是独立使用。