log4j 1.x 到 2.x 迁移时出现错误“没有可用于 AsyncAppender ASYNC 的附加程序”

Question

I am getting error 'Exception in thread "main" java.lang.ExceptionInInitializerError Caused by: org.apache.logging.log4j.core.config.ConfigurationException: No appenders are available for AsyncAppender ASYNC' while migrating from log4j1.x to log4j 2.x using the Log4j 1.x bridge as per https://logging.apache.org/log4j/2.x/manual/migration.html .

I have tried to add 'CONSOLE' appender in appender-ref of 'ASYNC' appender but it didnt work for me.(reference : https://issues.apache.org/jira/browse/LOG4J2-894 )

Complete stack trace :

Exception in thread "main" java.lang.ExceptionInInitializerError Caused by: org.apache.logging.log4j.core.config.ConfigurationException: No appenders are available for AsyncAppender ASYNC at org.apache.logging.log4j.core.appender.AsyncAppender.start(AsyncAppender.java:117) at org.apache.logging.log4j.core.config.AbstractConfiguration.start(AbstractConfiguration.java:255) at org.apache.logging.log4j.core.LoggerContext.setConfiguration(LoggerContext.java:530) at org.apache.logging.log4j.core.LoggerContext.reconfigure(LoggerContext.java:603) at org.apache.logging.log4j.core.LoggerContext.reconfigure(LoggerContext.java:620) at org.apache.logging.log4j.core.LoggerContext.start(LoggerContext.java:226) at org.apache.logging.log4j.core.impl.Log4jContextFactory.getContext(Log4jContextFactory.java:152) at org.apache.logging.log4j.core.impl.Log4jContextFactory.getContext(Log4jContextFactory.java:45) at org.apache.logging.log4j.LogManager.getContext(LogManager.java:307) at org.apache.log4j.LogMana ger$PrivateManager.getContext(LogManager.java:215) at org.apache.log4j.LogManager.getLogger(LogManager.java:74) at org.slf4j.impl.Log4jLoggerFactory.getLogger(Log4jLoggerFactory.java:73) at org.slf4j.LoggerFactory.getLogger(LoggerFactory.java:277) at org.apache.commons.logging.impl.SLF4JLogFactory.getInstance(SLF4JLogFactory.java:155) at org.apache.commons.logging.impl.SLF4JLogFactory.getInstance(SLF4JLogFactory.java:132) at org.apache.commons.logging.LogFactory.getLog(LogFactory.java:657) at org.springframework.context.support.AbstractApplicationContext.(AbstractApplicationContext.java:159) at org.springframework.context.support.AbstractApplicationContext.(AbstractApplicationContext.java:223) at org.springframework.context.support.AbstractRefreshableApplicationContext.(AbstractRefreshableApplicationContext.java:88) at org.springframework.context.support.AbstractRefreshableConfigApplicationContext.(AbstractRefreshableConfigApplicationContext.java:58) at org.springframework.context.supp ort.AbstractXmlApplicationContext.(AbstractXmlApplicationContext.java:61) at org.springframework.context.support.ClassPathXmlApplicationContext.(ClassPathXmlApplicationContext.java:136) at org.springframework.context.support.ClassPathXmlApplicationContext.(ClassPathXmlApplicationContext.java:83) at com.sm.common.business.security.StrongMailSymmetricEncryptionUtility.(StrongMailSymmetricEncryptionUtility.java:53)

**My log4j2.xml **:

<?xml version="1.0" encoding="UTF-8"?>
<Configuration>
  <Appenders>
    <Async name="ASYNC">
      <AppenderRef ref="R"/>
      <AppenderRef ref="CONSOLE"/>
    </Async>
   <Async name="ASYNC_WARN">
     <ThresholdFilter level="WARN"/>
     <AppenderRef ref="R"/>
     <AppenderRef ref="CONSOLE"/>
   </Async
    <Console name="CONSOLE" target="SYSTEM_OUT">
      <PatternLayout pattern="%d %-5p [%t] %C{2} - %m%n"/>
    </Console>   
 </Appenders>

 <Loggers>    
    <Logger name="com.sm" level="WARN" additivity="false">
      <AppenderRef ref="ASYNC"/>
    </Logger> 
    <Logger name="com.sm.random" level="WARN" additivity="false">
      <AppenderRef ref="ASYNC_WARN"/>
    </Logger> 
    <Logger name="com.sm.services" level="WARN" additivity="false">
      <AppenderRef ref="ASYNC"/>
    </Logger>

    <Root level="WARN">
      <AppenderRef ref="ASYNC"/>
    </Root>
  </Loggers>
</Configuration>

Thanks.

Answer 1

There could be multiple reason this exception occurs. Below are some:

1) There are duplicate log4j configuration in the project or inside the dependent jar you are using

2) No appenders added in log4j file

3) If appenders are added correctly then two or more log4j configuration are clashing.

In my case, this was happening due to two log4j2.xml file was configured.

Answer 2

The <Async name="ASYNC">... appender should be defined after the Appenders that it references. For example, the console appender is defined after the Async appender; it should be before.

Also, the Async appender has a <AppenderRef ref="R"/> that refers to a non-existing appender with name R. You need to either remove this AppenderRef or define the appender.

Answer 3

就我而言，这是由于日志目录访问权限被拒绝而发生的