如何從JNDI加載log4j2配置文件

Question

我正在將一些Web應用程序從Log4j 1.12遷移到Log4j2。由於公司政策，我們的log4j.xml文件位置被配置爲應用程序服務器中的URL，應用程序必須使用JNDI獲取它們。我們實現了一個ServletContextListener，使我們能夠初始化log4j的infraestructure這樣：

public void contextInitialized(ServletContextEvent servletContextEvent) { 
    ... 
    urlLogConfig = (URL) context.lookup("java:comp/env/"+logLocation); 
    ... 
    //urlLogConfig -> file:///somepath/log4j.xml 
    DOMConfigurator.configureAndWatch(urlLogConfig.getPath()); 
} 
public void contextDestroyed(ServletContextEvent servletContextEvent) { 
    ServletContext servletContext = servletContextEvent.getServletContext(); 
    servletContext.log("Log4jConfigurationListener - Shutting down log4j"); 
    LogManager.shutdown(); 
} 

然而，隨着log4j2 API改變了這種無法再使用。 Log4j2提供了使用Log4jServletContainerInitializer初始化庫的lo4j2-web.jar模塊。最後調用Log4jWebInitializerImpl.getConfigURI()，負責獲取配置文件的URI。

是否有任何方法來自定義Log4jWebInitializerImpl的行爲，使其從JNDI名稱解析XML文件？

Answer 1

如何像：

... 
import org.apache.logging.log4j.core.config.Configurator; 
... 

    private LoggerContext loggerContext; 

    public void contextInitialized(ServletContextEvent servletContextEvent) { 
     ... 
     urlLogConfig = (URL) context.lookup("java:comp/env/"+logLocation); 
     ... 
     //urlLogConfig -> file:///somepath/log4j.xml 
     ServletContext servletContext = servletContextEvent.getServletContext(); 
     String contextName = servletContext.getServletContextName(); 
     Classloader classloader = this.getClass().getClassloader(); 
     loggerContext = Configurator.initialize(contextName, classloader, urlLogConfig.toURI()); 
    } 

    public void contextDestroyed(ServletContextEvent servletContextEvent) { 
     ServletContext servletContext = servletContextEvent.getServletContext(); 
     servletContext.log("Log4jConfigurationListener - Shutting down log4j"); 
     if (loggerContext != null) 
      Configurator.shutdown(loggerContext); 
    }