Log4j 2 内存泄漏

Question

我使用 Tomcat 10.0.6、log4j 2.14.1。当我关闭 Tomcat 时，我会看到以下日志：

13-Nov-2021 22:32:32.915 SEVERE [main] org.apache.catalina.loader.WebappClassLoaderBase.checkThreadLocalMapForLeaks The web application [airline] created a ThreadLocal with key of type [java.lang.ThreadLocal] (value [java.lang.ThreadLocal@59402b8f]) and a value of type [org.apache.logging.log4j.core.impl.MutableLogEvent] (value [org.apache.logging.log4j.core.impl.MutableLogEvent@7188af83]) but failed to remove it when the web application was stopped. Threads are going to be renewed over time to try and avoid a probable memory leak.
13-Nov-2021 22:32:32.915 SEVERE [main] org.apache.catalina.loader.WebappClassLoaderBase.checkThreadLocalMapForLeaks The web application [airline] created a ThreadLocal with key of type [java.lang.ThreadLocal] (value [java.lang.ThreadLocal@6be968ce]) and a value of type [org.apache.logging.log4j.core.pattern.DatePatternConverter.PatternFormatter] (value [org.apache.logging.log4j.core.pattern.DatePatternConverter$PatternFormatter@7c37508a]) but failed to remove it when the web application was stopped. Threads are going to be renewed over time to try and avoid a probable memory leak.
13-Nov-2021 22:32:32.917 SEVERE [main] org.apache.catalina.loader.WebappClassLoaderBase.checkThreadLocalMapForLeaks The web application [airline] created a ThreadLocal with key of type [java.lang.ThreadLocal] (value [java.lang.ThreadLocal@247310d0]) and a value of type [org.apache.logging.log4j.message.ReusableSimpleMessage] (value [org.apache.logging.log4j.message.ReusableSimpleMessage@1033576a]) but failed to remove it when the web application was stopped. Threads are going to be renewed over time to try and avoid a probable memory leak.
13-Nov-2021 22:32:32.917 SEVERE [main] org.apache.catalina.loader.WebappClassLoaderBase.checkThreadLocalMapForLeaks The web application [airline] created a ThreadLocal with key of type [java.lang.ThreadLocal] (value [java.lang.ThreadLocal@303cf2ba]) and a value of type [org.apache.logging.log4j.core.pattern.DatePatternConverter.PatternFormatter] (value [org.apache.logging.log4j.core.pattern.DatePatternConverter$PatternFormatter@76494737]) but failed to remove it when the web application was stopped. Threads are going to be renewed over time to try and avoid a probable memory leak.
13-Nov-2021 22:32:32.921 SEVERE [main] org.apache.catalina.loader.WebappClassLoaderBase.checkThreadLocalMapForLeaks The web application [airline] created a ThreadLocal with key of type [java.lang.ThreadLocal] (value [java.lang.ThreadLocal@59402b8f]) and a value of type [org.apache.logging.log4j.core.impl.MutableLogEvent] (value [org.apache.logging.log4j.core.impl.MutableLogEvent@17fc391b]) but failed to remove it when the web application was stopped. Threads are going to be renewed over time to try and avoid a probable memory leak.
13-Nov-2021 22:32:32.921 SEVERE [main] org.apache.catalina.loader.WebappClassLoaderBase.checkThreadLocalMapForLeaks The web application [airline] created a ThreadLocal with key of type [java.lang.ThreadLocal] (value [java.lang.ThreadLocal@6be968ce]) and a value of type [org.apache.logging.log4j.core.pattern.DatePatternConverter.PatternFormatter] (value [org.apache.logging.log4j.core.pattern.DatePatternConverter$PatternFormatter@2b30a42c]) but failed to remove it when the web application was stopped. Threads are going to be renewed over time to try and avoid a probable memory leak.
13-Nov-2021 22:32:32.926 SEVERE [main] org.apache.catalina.loader.WebappClassLoaderBase.checkThreadLocalMapForLeaks The web application [airline] created a ThreadLocal with key of type [java.lang.ThreadLocal] (value [java.lang.ThreadLocal@247310d0]) and a value of type [org.apache.logging.log4j.message.ReusableSimpleMessage] (value [org.apache.logging.log4j.message.ReusableSimpleMessage@609e8838]) but failed to remove it when the web application was stopped. Threads are going to be renewed over time to try and avoid a probable memory leak.

log4j2.xml

<Configuration>
    <Properties>
        <Property name="property_console">%d{HH:mm:ss} %-5level %logger{1} - %msg%n</Property>
        <Property name="property_file">
            %d{yyyy-MM-dd HH:mm:ss} %-5level [%t] %logger{6} - %msg%n
        </Property>
    </Properties>
    <Appenders>
        <Console name="Console" target="SYSTEM_OUT">
            <PatternLayout pattern="${property_console}"/>
        </Console>
        <RollingFile name="FileRolling" fileName="logs/log.txt" append="true" filePattern="logs/${date:yyyy-MM-dd}/%d{yyyy-MM-dd_HH-mm}.txt">
            <PatternLayout pattern="${property_file}"/>
            <Policies>
                <SizeBasedTriggeringPolicy size="100 K"/>
            </Policies>
            <DefaultRolloverStrategy max="10"/>
        </RollingFile>
    </Appenders>
    <Loggers>
        <Root level="ALL">
            <AppenderRef ref="FileRolling"/>
            <AppenderRef ref="Console"/>
        </Root>
    </Loggers>
</Configuration>

我的log4j2pom.xml

<dependency>
        <groupId>org.apache.logging.log4j</groupId>
        <artifactId>log4j-web</artifactId>
        <version>2.14.1</version>
</dependency>

我认为这可能与我使用 jakarta.servlet 3.0 依赖项有关，但我不知道。 将 .jar 移动到 tomcat/lib 不会得到任何更改。有什么问题？

Answer 1

您的假设是正确的：log4j-web 需要支持 ServletContainerInitializers，这是在 Servlet 3.0 中引入的。

自 Servlet 5.0（Tomcat 10 实现）以来，由于 Oracle 和 Eclipse 基金会之间的版权纠纷，该类的全名从 javax.servlet.ServletContainerInitializer 更改为 jakarta.servlet.ServletContainerInitializer。因此，log4j-web 的所有版本都不适用于 Tomcat 10。

编辑：从 Log4j 2.15.0 开始，可以使用支持 Jakarta EE 9+ 服务器的 log4j-web 版本：log4j-jakarta-web，它解决了功能请求 LOG4J2-2978。