使用ServletContextListener和SLF4J在contextDestroyed上没有日志输出

Question

我正在尝试向记录器写一条消息(Vaadin)servlet已停止,这使用SLF4J和Log4j2.

为此,我使用的是ServletContextListener在应用程序启动时记录消息.但是在登录contextDestroyed方法时我无法获得任何输出...这是我的实现:

@WebListener
public class VaadinLogger implements ServletContextListener {

    private static final Logger logger = LoggerFactory.getLogger(VaadinLogger.class);

    @Override
    public void contextInitialized(ServletContextEvent contextEvent) {
        // Remove appenders from JUL loggers
        SLF4JBridgeHandler.removeHandlersForRootLogger();

        // Install bridge
        SLF4JBridgeHandler.install();

        // Get servlet context
        ServletContext context = contextEvent.getServletContext();

        // Retrieve name
        String name = context.getServletContextName();

        // Log servlet init information
        logger.info("Start \"{}\"", name);
    }

    @Override
    public void contextDestroyed(ServletContextEvent contextEvent) {
        // Get servlet context
        ServletContext context = contextEvent.getServletContext();

        // Retrieve name
        String name = context.getServletContextName();

        // Log servlet destroy information
        logger.info("End \"{}\"{}", name, System.lineSeparator()));

        // Uninstall bridge
        SLF4JBridgeHandler.uninstall();
    }
}

在这一点上,我猜这可能是因为在contextDestroyed调用点时,不再可能进行日志记录,因为它们已经被垃圾收集器破坏了.

所以现在我的问题是,是否可以在销毁上下文之前记录servlet已停止,或者在log4j2记录器被销毁之前使contextlistener执行？

提前致谢!

Answer 1

从 log4j 2.14.1 开始，您可以禁用自动关闭并添加侦听器来停止记录器。

<context-param>
    <!-- auto-shutdown stops log4j when the web fragment unloads, but that
         is too early because it is before the listeners shut down. To 
         compensate, use a Log4jShutdownOnContextDestroyedListener and
         register it before any other listeners which means it will shut
         down *after* all other listeners. -->
    <param-name>isLog4jAutoShutdownDisabled</param-name>
    <param-value>true</param-value>
</context-param>    

<listener>
   <!-- ensure logging stops after other listeners by registering
        the shutdown listener first -->
    <listener-class>
       org.apache.logging.log4j.web.Log4jShutdownOnContextDestroyedListener
    </listener-class>
</listener>
<listener>
    <listener-class>
        org.springframework.web.context.ContextLoaderListener
    </listener-class>
</listener>