java - 来自 log4j2 的奇怪日志

Question

我在 Tomcat 8 中运行一个应用程序，它使用 log4j2。一切正常，但每当我尝试记录某些内容时，Tomcat 的 stderr 中会出现以下消息:

ERROR Unable to create Lookup for web java.lang.ClassCastException: class org.apache.logging.log4j.web.WebLookup
    at java.lang.Class.asSubclass(Class.java:3396)
    at org.apache.logging.log4j.core.lookup.Interpolator.<init>(Interpolator.java:64)
    at org.apache.logging.log4j.core.config.PropertiesPlugin.configureSubstitutor(PropertiesPlugin.java:57)
    at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
    at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:62)
    at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
    at java.lang.reflect.Method.invoke(Method.java:483)
    at org.apache.logging.log4j.core.config.plugins.util.PluginBuilder.build(PluginBuilder.java:135)
    at org.apache.logging.log4j.core.config.AbstractConfiguration.createPluginObject(AbstractConfiguration.java:766)
    at org.apache.logging.log4j.core.config.AbstractConfiguration.createConfiguration(AbstractConfiguration.java:706)
    at org.apache.logging.log4j.core.config.AbstractConfiguration.doConfigure(AbstractConfiguration.java:339)
    at org.apache.logging.log4j.core.config.AbstractConfiguration.start(AbstractConfiguration.java:161)
    at org.apache.logging.log4j.core.LoggerContext.setConfiguration(LoggerContext.java:359)
....

这是怎么回事？

正如我所说，一切正常，但我不希望看到此消息，因为它看起来好像出了点问题。

Answer 1

您可能缺少 log4j-web 依赖项

<dependency>
    <groupId>org.apache.logging.log4j</groupId>
    <artifactId>log4j-web</artifactId>
    <version>2.16.0</version>
</dependency>