如何将Log4j彻底切换成logback

最新推荐文章于 2024-09-20 12:59:40 发布

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最新推荐文章于 2024-09-20 12:59:40 发布

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分类专栏： JAVA SE J2EE 文章标签： log4j logback

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本文详细介绍了如何将项目的日志框架从Log4j彻底切换到logback，包括排除Log4j相关依赖以及桥接其他使用Log4j的日志框架到slf4j，确保项目不直接依赖具体日志实现。

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如何将Log4j彻底切换成logback?

之前有篇文章《彻底搞明白为什么日志框架依赖冲突了》介绍了同一项目中因为依赖了多个日志实现而导致的异常。log4j和logback都是日志实现，通常情况下，我们项目中都不会直接使用实现类，而是使用slf4j、jcl、log4j-api等日志facade。这样最大的好处就是，项目不会和某一日志框架绑定。

本篇将介绍如果把项目的日志框架切换成logback，切成其它的实现同理实现即可。

1、排除项目中所有的log4j、log4j-core相关的依赖。

这里推荐idea插件Maven helper工具，来查看和管理依赖。
在这里插入图片描述
在这个界面上可以查到项目中直接依赖和间接依赖的所有的log4j的jar，然后选中右键排除即可。

2、桥接其它日志框架到slf4j

如果某个jar破坏了“我们项目中都不会直接使用实现类”这个原则，直接使用了log4j里面的类，那怎么办？排掉项目就回报错，比如：

2021-12-29 14:50:12 ERROR c.q.b.d.c.GlobalDefaultExceptionHandler - Exception occurred: Handler dispatch failed; nested exception is java.lang.NoClassDefFoundError: org/apache/log4j/Level
org.springframework.web.util.NestedServletException: Handler dispatch failed; nested exception is java.lang.NoClassDefFoundError: org/apache/log4j/Level
	at org.springframework.web.servlet.DispatcherServlet.doDispatch(DispatcherServlet.java:1006)
	at org.springframework.web.servlet.DispatcherServlet.doService(DispatcherServlet.java:925)
	at org.springframework.web.servlet.FrameworkServlet.processRequest(FrameworkServlet.java:974)
	at org.springframework.web.servlet.FrameworkServlet.doGet(FrameworkServlet.java:866)
	at javax.servlet.http.HttpServlet.service(HttpServlet.java:503)
	at org.springframework.web.servlet.FrameworkServlet.service(FrameworkServlet.java:851)
	at javax.servlet.http.HttpServlet.service(HttpServlet.java:590)
	at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:231)
	at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:166)
	at org.apache.tomcat.websocket.server.WsFilter.doFilter(WsFilter.java:52)
	at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:193)
	at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:166)
	at org.springframework.web.filter.CorsFilter.doFilterInternal(CorsFilter.java:96)
	at org.springframework.web.filter.OncePerRequestFilter.doFilter(OncePerRequestFilter.java:107)
	at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:193)
	at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:166)
	at org.springframework.boot.actuate.web.trace.servlet.HttpTraceFilter.doFilterInternal(HttpTraceFilter.java:90)
	at org.springframework.web.filter.OncePerRequestFilter.doFilter(OncePerRequestFilter.java:107)
	at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:193)
	at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:166)
	at com.qihoo.bigdata.qsso.client.V2.AuthenticationFilter.doFilter(AuthenticationFilter.java:48)
	at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:193)
	at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:166)
	at org.springframework.web.filter.RequestContextFilter.doFilterInternal(RequestContextFilter.java:99)
	at org.springframework.web.filter.OncePerRequestFilter.doFilter(OncePerRequestFilter.java:107)
	at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:193)
	at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:166)
	at org.springframework.web.filter.HttpPutFormContentFilter.doFilterInternal(HttpPutFormContentFilter.java:109)
	at org.springframework.web.filter.OncePerRequestFilter.doFilter(OncePerRequestFilter.java:107)
	at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:193)
	at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:166)
	at org.springframework.web.filter.HiddenHttpMethodFilter.doFilterInternal(HiddenHttpMethodFilter.java:93)
	at org.springframework.web.filter.OncePerRequestFilter.doFilter(OncePerRequestFilter.java:107)
	at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:193)
	at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:166)
	at org.springframework.boot.actuate.metrics.web.servlet.WebMvcMetricsFilter.filterAndRecordMetrics(WebMvcMetricsFilter.java:155)
	at org.springframework.boot.actuate.metrics.web.servlet.WebMvcMetricsFilter.filterAndRecordMetrics(WebMvcMetricsFilter.java:123)
	at org.springframework.boot.actuate.metrics.web.servlet.WebMvcMetricsFilter.doFilterInternal(WebMvcMetricsFilter.java:108)
	at org.springframework.web.filter.OncePerRequestFilter.doFilter(OncePerRequestFilter.java:107)
	at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:193)
	at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:166)
	at org.springframework.web.filter.CharacterEncodingFilter.doFilterInternal(CharacterEncodingFilter.java:200)
	at org.springframework.web.filter.OncePerRequestFilter.doFilter(OncePerRequestFilter.java:107)
	at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:193)
	at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:166)
	at org.apache.catalina.core.StandardWrapperValve.invoke(StandardWrapperValve.java:198)
	at org.apache.catalina.core.StandardContextValve.invoke(StandardContextValve.java:96)
	at org.apache.catalina.authenticator.AuthenticatorBase.invoke(AuthenticatorBase.java:493)
	at org.apache.catalina.core.StandardHostValve.invoke(StandardHostValve.java:140)
	at org.apache.catalina.valves.ErrorReportValve.invoke(ErrorReportValve.java:81)
	at org.apache.catalina.core.StandardEngineValve.invoke(StandardEngineValve.java:87)
	at org.apache.catalina.connector.CoyoteAdapter.service(CoyoteAdapter.java:342)
	at org.apache.coyote.http11.Http11Processor.service(Http11Processor.java:800)
	at org.apache.coyote.AbstractProcessorLight.process(AbstractProcessorLight.java:66)
	at org.apache.coyote.AbstractProtocol$ConnectionHandler.process(AbstractProtocol.java:800)
	at org.apache.tomcat.util.net.NioEndpoint$SocketProcessor.doRun(NioEndpoint.java:1471)
	at org.apache.tomcat.util.net.SocketProcessorBase.run(SocketProcessorBase.java:49)
	at java.base/java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1128)
	at java.base/java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:628)
	at org.apache.tomcat.util.threads.TaskThread$WrappingRunnable.run(TaskThread.java:61)
	at java.base/java.lang.Thread.run(Thread.java:834)
Caused by: java.lang.NoClassDefFoundError: org/apache/log4j/Level
	at org.apache.hadoop.mapred.JobConf.<clinit>(JobConf.java:357)
	at java.base/java.lang.Class.forName0(Native Method)
	at java.base/java.lang.Class.forName(Class.java:398)
	at org.apache.hadoop.conf.Configuration.getClassByNameOrNull(Configuration.java:2134)
	at org.apache.hadoop.util.ReflectionUtils.setJobConf(ReflectionUtils.java:95)
	at org.apache.hadoop.util.ReflectionUtils.setConf(ReflectionUtils.java:78)
	at org.apache.hadoop.util.ReflectionUtils.newInstance(ReflectionUtils.java:136)
	at org.apache.hadoop.fs.FileSystem.createFileSystem(FileSystem.java:2668)
	at org.apache.hadoop.fs.FileSystem.access$200(FileSystem.java:94)
	at org.apache.hadoop.fs.FileSystem$Cache.getInternal(FileSystem.java:2703)
	at org.apache.hadoop.fs.FileSystem$Cache.getUnique(FileSystem.java:2691)
	at org.apache.hadoop.fs.FileSystem.newInstance(FileSystem.java:420)
	at org.apache.hadoop.fs.FileSystem$2.run(FileSystem.java:395)
	at org.apache.hadoop.fs.FileSystem$2.run(FileSystem.java:392)
	at java.base/java.security.AccessController.doPrivileged(Native Method)
	at java.base/javax.security.auth.Subject.doAs(Subject.java:423)

跟进源码，发现
在这里插入图片描述
hadoop-mapreduce-client-core/jobConf.java中直接引用了log4j的Level类。
slf4j早就考虑到这种情况了，提供了各种日志框架到slf4j的桥接类

这里我们只需要在项目中引用log4j-over-slf4j就行了。