Log4j2 Servlet附录

Question

我使用Tomcat 10 (实际上是TomEE，但它在下面使用Tomcat 10 )，我正在尝试设置log4j2日志记录。我让这一半工作在控制台日志记录中进行(我在catalina.log中有日志输出)。我无法工作的是'Servlet‘附录。在log4j2文档中，我将此作为配置

<Configuration status="DEBUG" name="MyBlog">
    <Appenders>
        <Console name="Console" target="SYSTEM_OUT">
            <PatternLayout pattern="%d{HH:mm:ss.SSS} [%t] %-5level %logger{36} - %msg%n"/>
        </Console>
        <Servlet name="Servlet">
            <PatternLayout pattern="%m%n%ex{none}"/>
        </Servlet>
    </Appenders>
    <Loggers>
        <Root level="DEBUG">
            <AppenderRef ref="Console"/>
            <AppenderRef ref="Servlet"/>
        </Root>
    </Loggers>

</Configuration>

在我的web.xml里

    <context-param>
        <param-name>log4jContextName</param-name>
        <param-value>myblog</param-value>
    </context-param>

我部署了三个log4j2 jars，log4j-core、log4j-api和log4j-web，它的版本为2.17.1。

我在日志中看到了三个错误：

2022-01-18 17:42:59,381 http-nio-8080-exec-16 ERROR No servlet context is available
2022-01-18 17:42:59,383 http-nio-8080-exec-16 ERROR Null object returned for Servlet in Appenders.
2022-01-18 17:42:59,386 http-nio-8080-exec-16 ERROR Unable to locate appender "Servlet" for logger config "root"

任何感激之情

加入-Dlog4j2.debug=true后

我看到这个

DEBUG StatusLogger ServletAppender$Builder(logThrowables="null", ignoreExceptions="null", PatternLayout(%m%n%ex{none}), name="Servlet", Configuration(MyBlog), Filter=null, ={})
ERROR StatusLogger No servlet context is available
DEBUG StatusLogger Building Plugin[name=appenders, class=org.apache.logging.log4j.core.config.AppendersPlugin].
ERROR StatusLogger Null object returned for Servlet in Appenders.
DEBUG StatusLogger createAppenders(={Console, })
DEBUG StatusLogger Building Plugin[name=AppenderRef, class=org.apache.logging.log4j.core.config.AppenderRef].
DEBUG StatusLogger createAppenderRef(ref="Console", level="null", Filter=null)
DEBUG StatusLogger Building Plugin[name=AppenderRef, class=org.apache.logging.log4j.core.config.AppenderRef].
DEBUG StatusLogger createAppenderRef(ref="Servlet", level="null", Filter=null)
DEBUG StatusLogger Building Plugin[name=root, class=org.apache.logging.log4j.core.config.LoggerConfig$RootLogger].
DEBUG StatusLogger createLogger(additivity="null", level="DEBUG", includeLocation="null", ={Console, Servlet}, ={}, Configuration(MyBlog), Filter=null)
DEBUG StatusLogger Building Plugin[name=loggers, class=org.apache.logging.log4j.core.config.LoggersPlugin].
DEBUG StatusLogger createLoggers(={root})
ERROR StatusLogger Unable to locate appender "Servlet" for logger config "root"

顺便说一句，如果我将日志级别设置为在控制台附录中进行调试，就会得到类似的输出。

Answer 1

由于Java 8和Jakarta 9之间的命名空间更改(cf )。例如，月食网站 )您需要使用log4j-jakarta-web而不是log4j-web。

在Maven格式中，您需要：

<dependency>
    <groupId>org.apache.logging.log4j</groupId>
    <artifactId>log4j-jakarta-web</artifactId>
    <version>2.17.1</version>
</dependency>

编辑：在log4j-jakarta-web中似乎有一个小错误，它阻止了ServletContainerInitializer的启动。我加了PR #723。同时，您可以在您的Log4jServletContextListener中声明web.xml

  <listener>
    <description>Initializes Log4j 2.x</description>
    <listener-class>org.apache.logging.log4j.web.Log4jServletContextListener</listener-class>
  </listener>