这是我的log4j2.xml文件（缩写，还有4个附加程序和记录器，但它们的格式完全相同）
<?xml version="1.0" encoding="UTF-8"?>
<Configuration status="trace" name="ventusproxy" packages="">
<Appenders>
<RollingFile name="ACCESS_LOG"
filePattern="${sys:log.dir}vproxy_access.%d{yyyy-MM-dd}"
append="true"
immediateFlush="false">
<PatternLayout>
<Pattern>%m%d{yyyy-MM-dd HH:mm:ss}%n</Pattern>
</PatternLayout>
<Policies>
<TimeBasedTriggeringPolicy/>
</Policies>
</RollingFile>
</Appenders>
<Loggers>
<Root level="off" additivity="false" />
<Logger name="LOGGER_ACCESS" level="info" includeLocation="true" additivity="false">
<AppenderRef ref="ACCESS_LOG"/>
</Logger>
</Loggers>
</Configuration>
我们使用以下选项启动tomcat：
-DLog4jContextSelector=org.apache.logging.log4j.core.async.AsyncLoggerContextSelector
因此，我们启用了完全异步日志记录。这就是为什么我们只使用Logger和Root而不是AsyncLogger和AsyncRoot的原因。
tomcat启动时，我们可以看到：
2018-08-07 21:03:56,535 localhost-startStop-1 TRACE Using default SystemClock for timestamps.
2018-08-07 21:03:56,536 localhost-startStop-1 TRACE Using DummyNanoClock for nanosecond timestamps.
2018-08-07 21:03:56,536 localhost-startStop-1 DEBUG Reconfiguration complete for context[name=AsyncContext@4d8d549e] at URI /home/ventusproxy/app/ROOT/WEB-INF/log4j.xml (org.apache.logging.log4j.core.async.AsyncLoggerContext@2c9ae56e) with optional ClassLoader: null
2018-08-07 21:03:56,536 localhost-startStop-1 DEBUG Shutdown hook enabled. Registering a new one.
2018-08-07 21:03:56,537 localhost-startStop-1 DEBUG LoggerContext[name=AsyncContext@4d8d549e, org.apache.logging.log4j.core.async.AsyncLoggerContext@2c9ae56e] started OK.
2018-08-07 21:03:56,538 localhost-startStop-1 TRACE Using default SystemClock for timestamps.
2018-08-07 21:03:56,539 localhost-startStop-1 DEBUG AsyncLogger.ThreadNameStrategy=CACHED
2018-08-07 21:03:56,556 Log4j2-TF-1-AsyncLogger[AsyncContext@4d8d549e]-1 DEBUG Now writing to /home/ventusproxy/logs/vproxy_system.2018-08-07 at 2018-08-07T21:03:56.556-0400
2018-08-07 21:03:57,081 localhost-startStop-1 DEBUG PluginManager 'Converter' found 42 plugins
2018-08-07 21:03:57,082 localhost-startStop-1 DEBUG Starting OutputStreamManager SYSTEM_OUT.false.false-2
2018-08-07 21:03:57,083 localhost-startStop-1 TRACE [DefaultAsyncContext@localhost-startStop-1] AsyncLoggerDisruptor creating new disruptor for this context.
2018-08-07 21:03:57,083 localhost-startStop-1 TRACE property AsyncLogger.WaitStrategy=TIMEOUT
2018-08-07 21:03:57,092 localhost-startStop-1 DEBUG [DefaultAsyncContext@localhost-startStop-1] Starting AsyncLogger disruptor for this context with ringbufferSize=262144, waitStrategy=TimeoutBlockingWaitStrategy, exceptionHandler=org.apache.logging.log4j.core.async.AsyncLoggerDefaultExceptionHandler@71fd86cb...
2018-08-07 21:03:57,093 localhost-startStop-1 TRACE [DefaultAsyncContext@localhost-startStop-1] AsyncLoggers use a threadlocal translator
2018-08-07 21:03:57,093 localhost-startStop-1 DEBUG Starting LoggerContext[name=DefaultAsyncContext@localhost-startStop-1, org.apache.logging.log4j.core.async.AsyncLoggerContext@77ae266d]...
2018-08-07 21:03:57,094 localhost-startStop-1 DEBUG Reconfiguration started for context[name=DefaultAsyncContext@localhost-startStop-1] at URI null (org.apache.logging.log4j.core.async.AsyncLoggerContext@77ae266d) with optional ClassLoader: null
2018-08-07 21:03:57,094 localhost-startStop-1 DEBUG Using configurationFactory org.apache.logging.log4j.core.config.ConfigurationFactory$Factory@4b6e6fdf
2018-08-07 21:03:57,133 localhost-startStop-1 DEBUG Initializing configuration XmlConfiguration[location=/home/ventusproxy/app/ROOT/WEB-INF/log4j.xml]
最后（最后一条调试行）：
2018-08-07 21:03:57,200 localhost-startStop-1 DEBUG LoggerContext[name=DefaultAsyncContext@localhost-startStop-1, org.apache.logging.log4j.core.async.AsyncLoggerContext@77ae266d] started OK.
但是，当我们使用JStack执行线程转储时，没有看到一个线程，而是看到了2个线程：
"Log4j2-TF-7-AsyncLogger[DefaultAsyncContext@localhost-startStop-1]-2" #23 daemon prio=5 os_prio=0 tid=0x00007f1ee8ad9800 nid=0x625d runnable [0x00007f1f05817000]
java.lang.Thread.State: TIMED_WAITING (parking)
at sun.misc.Unsafe.park(Native Method)
- parking to wait for <0x00000000925d3ad8> (a java.util.concurrent.locks.AbstractQueuedSynchronizer$ConditionObject)
at java.util.concurrent.locks.LockSupport.parkNanos(LockSupport.java:215)
at java.util.concurrent.locks.AbstractQueuedSynchronizer$ConditionObject.awaitNanos(AbstractQueuedSynchronizer.java:2078)
at com.lmax.disruptor.TimeoutBlockingWaitStrategy.waitFor(TimeoutBlockingWaitStrategy.java:38)
at com.lmax.disruptor.ProcessingSequenceBarrier.waitFor(ProcessingSequenceBarrier.java:56)
at com.lmax.disruptor.BatchEventProcessor.run(BatchEventProcessor.java:124)
at java.lang.Thread.run(Thread.java:748)
Locked ownable synchronizers:
- None
"Log4j2-TF-1-AsyncLogger[AsyncContext@4d8d549e]-1" #21 daemon prio=5 os_prio=0 tid=0x00007f1ee88d8800 nid=0x625c runnable [0x00007f1f06073000]
java.lang.Thread.State: TIMED_WAITING (parking)
at sun.misc.Unsafe.park(Native Method)
- parking to wait for <0x0000000093099540> (a java.util.concurrent.locks.AbstractQueuedSynchronizer$ConditionObject)
at java.util.concurrent.locks.LockSupport.parkNanos(LockSupport.java:215)
at java.util.concurrent.locks.AbstractQueuedSynchronizer$ConditionObject.awaitNanos(AbstractQueuedSynchronizer.java:2078)
at com.lmax.disruptor.TimeoutBlockingWaitStrategy.waitFor(TimeoutBlockingWaitStrategy.java:38)
at com.lmax.disruptor.ProcessingSequenceBarrier.waitFor(ProcessingSequenceBarrier.java:56)
at com.lmax.disruptor.BatchEventProcessor.run(BatchEventProcessor.java:124)
at java.lang.Thread.run(Thread.java:748)
Locked ownable synchronizers:
- None
当我们停止tomcat时，将记录所有这些错误：
07-Aug-2018 21:07:29.991 WARNING [localhost-startStop-2] org.apache.catalina.loader.WebappClassLoaderBase.clearReferencesThreads The web application [ROOT] appears to have started a thread named [Log4j2-TF-7-AsyncLogger[DefaultAsyncContext@localhost-startStop-1]-2] but has failed to stop it. This is very likely to create a memory leak. Stack trace of thread:
sun.misc.Unsafe.park(Native Method)
java.util.concurrent.locks.LockSupport.parkNanos(LockSupport.java:215)
java.util.concurrent.locks.AbstractQueuedSynchronizer$ConditionObject.awaitNanos(AbstractQueuedSynchronizer.java:2078)
com.lmax.disruptor.TimeoutBlockingWaitStrategy.waitFor(TimeoutBlockingWaitStrategy.java:38)
com.lmax.disruptor.ProcessingSequenceBarrier.waitFor(ProcessingSequenceBarrier.java:56)
com.lmax.disruptor.BatchEventProcessor.run(BatchEventProcessor.java:124)
java.lang.Thread.run(Thread.java:748)
07-Aug-2018 21:07:29.993 SEVERE [localhost-startStop-2] org.apache.catalina.loader.WebappClassLoaderBase.checkThreadLocalMapForLeaks The web application [ROOT] created a ThreadLocal with key of type [java.lang.ThreadLocal] (value [java.lang.ThreadLocal@494a6bc6]) and a value of type [org.apache.logging.log4j.core.async.RingBufferLogEventTranslator] (value [org.apache.logging.log4j.core.async.RingBufferLogEventTranslator@46d89786]) 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.
07-Aug-2018 21:07:29.993 SEVERE [localhost-startStop-2] org.apache.catalina.loader.WebappClassLoaderBase.checkThreadLocalMapForLeaks The web application [ROOT] created a ThreadLocal with key of type [java.lang.ThreadLocal] (value [java.lang.ThreadLocal@494a6bc6]) and a value of type [org.apache.logging.log4j.core.async.RingBufferLogEventTranslator] (value [org.apache.logging.log4j.core.async.RingBufferLogEventTranslator@7fca5b63]) 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.
07-Aug-2018 21:07:29.994 SEVERE [localhost-startStop-2] org.apache.catalina.loader.WebappClassLoaderBase.checkThreadLocalMapForLeaks The web application [ROOT] created a ThreadLocal with key of type [java.lang.ThreadLocal] (value [java.lang.ThreadLocal@7d2c87bb]) and a value of type [org.apache.logging.log4j.core.async.RingBufferLogEventTranslator] (value [org.apache.logging.log4j.core.async.RingBufferLogEventTranslator@316c8d06]) 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.
07-Aug-2018 21:07:29.994 SEVERE [localhost-startStop-2] org.apache.catalina.loader.WebappClassLoaderBase.checkThreadLocalMapForLeaks The web application [ROOT] created a ThreadLocal with key of type [java.lang.ThreadLocal] (value [java.lang.ThreadLocal@74afa5d5]) and a value of type [org.apache.logging.log4j.core.async.RingBufferLogEventTranslator] (value [org.apache.logging.log4j.core.async.RingBufferLogEventTranslator@5913f960]) 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.
07-Aug-2018 21:07:29.994 SEVERE [localhost-startStop-2] org.apache.catalina.loader.WebappClassLoaderBase.checkThreadLocalMapForLeaks The web application [ROOT] created a ThreadLocal with key of type [java.lang.ThreadLocal] (value [java.lang.ThreadLocal@401baca6]) and a value of type [org.apache.logging.log4j.core.async.RingBufferLogEventTranslator] (value [org.apache.logging.log4j.core.async.RingBufferLogEventTranslator@154a0d1e]) 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.
07-Aug-2018 21:07:29.995 SEVERE [localhost-startStop-2] org.apache.catalina.loader.WebappClassLoaderBase.checkThreadLocalMapForLeaks The web application [ROOT] created a ThreadLocal with key of type [java.lang.ThreadLocal] (value [java.lang.ThreadLocal@1cc2936f]) and a value of type [org.apache.logging.log4j.core.async.RingBufferLogEventTranslator] (value [org.apache.logging.log4j.core.async.RingBufferLogEventTranslator@5a5ca16e]) 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.
07-Aug-2018 21:07:29.995 SEVERE [localhost-startStop-2] org.apache.catalina.loader.WebappClassLoaderBase.checkThreadLocalMapForLeaks The web application [ROOT] created a ThreadLocal with key of type [java.lang.ThreadLocal] (value [java.lang.ThreadLocal@473f581f]) and a value of type [org.apache.logging.log4j.core.async.RingBufferLogEventTranslator] (value [org.apache.logging.log4j.core.async.RingBufferLogEventTranslator@2d89f1b]) 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.
仅3个问题，因为现在我不确定是否在此处使用异步日志记录
使用这些跟踪信息可以确认我正在使用完全异步日志记录吗？
我已经读到异步日志记录仅从一个线程开始，但是在这里我看到了2（就像我们将同步日志记录和异步日志记录混合在一起一样）。这是真的吗？
如何从catalina.out中删除这些错误？该应用程序可以正确停止，因此这些消息并不是真正的问题，但我希望尽可能将其删除。