Tomcat ClassNotFoundException: org.slf4j.spi.LoggerFactoryBinder 但 slf4j 在库中

Question

我不断收到以下错误：

Failed to instantiate SLF4J LoggerFactory
Reported exception:
java.lang.NoClassDefFoundError: org/slf4j/spi/LoggerFactoryBinder
        at java.lang.ClassLoader.defineClass1(Native Method)
        at java.lang.ClassLoader.defineClass(ClassLoader.java:800)
        at java.security.SecureClassLoader.defineClass(SecureClassLoader.java:142)
        at java.net.URLClassLoader.defineClass(URLClassLoader.java:449)
        at java.net.URLClassLoader.access$100(URLClassLoader.java:71)
        at java.net.URLClassLoader$1.run(URLClassLoader.java:361)
        at java.net.URLClassLoader$1.run(URLClassLoader.java:355)
        at java.security.AccessController.doPrivileged(Native Method)
        at java.net.URLClassLoader.findClass(URLClassLoader.java:354)
        at java.lang.ClassLoader.loadClass(ClassLoader.java:425)
        at java.lang.ClassLoader.loadClass(ClassLoader.java:358)
        at java.lang.Class.forName0(Native Method)
        at java.lang.Class.forName(Class.java:270)
        at org.apache.catalina.loader.WebappClassLoader.loadClass(WebappClassLoader.java:1562)
        at org.apache.catalina.loader.WebappClassLoader.loadClass(WebappClassLoader.java:1420)
        at org.slf4j.LoggerFactory.bind(LoggerFactory.java:129)
        at org.slf4j.LoggerFactory.performInitialization(LoggerFactory.java:108)
        at org.slf4j.LoggerFactory.getILoggerFactory(LoggerFactory.java:302)
        at org.slf4j.LoggerFactory.getLogger(LoggerFactory.java:276)
        at org.apache.commons.logging.impl.SLF4JLogFactory.getInstance(SLF4JLogFactory.java:156)
        at org.apache.commons.logging.impl.SLF4JLogFactory.getInstance(SLF4JLogFactory.java:132)
        at org.apache.commons.logging.LogFactory.getLog(LogFactory.java:274)
        at org.springframework.web.context.ContextLoader.initWebApplicationContext(ContextLoader.java:282)
        at org.springframework.web.context.ContextLoaderListener.contextInitialized(ContextLoaderListener.java:106)
        at org.apache.catalina.core.StandardContext.listenerStart(StandardContext.java:4830)
        at org.apache.catalina.core.StandardContext.startInternal(StandardContext.java:5276)
        at org.apache.catalina.util.LifecycleBase.start(LifecycleBase.java:150)
        at org.apache.catalina.core.ContainerBase.addChildInternal(ContainerBase.java:726)
        at org.apache.catalina.core.ContainerBase.addChild(ContainerBase.java:702)
        at org.apache.catalina.core.StandardHost.addChild(StandardHost.java:698)
        at org.apache.catalina.startup.HostConfig.deployWAR(HostConfig.java:968)
        at org.apache.catalina.startup.HostConfig$DeployWar.run(HostConfig.java:1742)
        at java.util.concurrent.Executors$RunnableAdapter.call(Executors.java:471)
        at java.util.concurrent.FutureTask.run(FutureTask.java:262)
        at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1145)
        at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:615)
        at java.lang.Thread.run(Thread.java:744)
Caused by: java.lang.ClassNotFoundException: org.slf4j.spi.LoggerFactoryBinder
        at java.net.URLClassLoader$1.run(URLClassLoader.java:366)
        at java.net.URLClassLoader$1.run(URLClassLoader.java:355)
        at java.security.AccessController.doPrivileged(Native Method)
        at java.net.URLClassLoader.findClass(URLClassLoader.java:354)
        at java.lang.ClassLoader.loadClass(ClassLoader.java:425)
        at java.lang.ClassLoader.loadClass(ClassLoader.java:358)
        ... 37 more
21-Jun-2014 17:06:51.352 SEVERE [localhost-startStop-1] org.apache.catalina.core.StandardContext.startInternal Error listenerStart
21-Jun-2014 17:06:51.358 SEVERE [localhost-startStop-1] org.apache.catalina.core.StandardContext.startInternal Context [/spring-app] startup failed due to previous errors
21-Jun-2014 17:06:51.399 INFO [localhost-startStop-1] org.apache.catalina.startup.HostConfig.deployDirectory Deploying web application directory /media/win/d/coding/servers/tomcat/apache-tomcat-8.0.0-RC5/webapps/docs
21-Jun-2014 17:06:51.829 INFO [localhost-startStop-1] org.apache.catalina.startup.HostConfig.deployDirectory Deploying web application directory /media/win/d/coding/servers/tomcat/apache-tomcat-8.0.0-RC5/webapps/examples
21-Jun-2014 17:06:53.181 INFO [localhost-startStop-1] org.apache.catalina.startup.HostConfig.deployDirectory Deploying web application directory /media/win/d/coding/servers/tomcat/apache-tomcat-8.0.0-RC5/webapps/host-manager
21-Jun-2014 17:06:53.575 INFO [localhost-startStop-1] org.apache.catalina.startup.HostConfig.deployDirectory Deploying web application directory /media/win/d/coding/servers/tomcat/apache-tomcat-8.0.0-RC5/webapps/manager
21-Jun-2014 17:06:53.950 INFO [localhost-startStop-1] org.apache.catalina.startup.HostConfig.deployDirectory Deploying web application directory /media/win/d/coding/servers/tomcat/apache-tomcat-8.0.0-RC5/webapps/ROOT
21-Jun-2014 17:06:54.324 INFO [main] org.apache.coyote.AbstractProtocol.start Starting ProtocolHandler ["http-nio-8080"]
21-Jun-2014 17:06:54.328 INFO [main] org.apache.coyote.AbstractProtocol.start Starting ProtocolHandler ["ajp-nio-8009"]
21-Jun-2014 17:06:54.329 INFO [main] org.apache.catalina.startup.Catalina.start Server startup in 9393 ms
21-Jun-2014 17:07:14.840 INFO [ContainerBackgroundProcessor[StandardEngine[Catalina]]] org.apache.catalina.startup.HostConfig.undeploy Undeploying context [/spring-app]
21-Jun-2014 17:07:44.907 INFO [localhost-startStop-2] org.apache.catalina.startup.HostConfig.deployWAR Deploying web application archive /media/win/d/coding/servers/tomcat/apache-tomcat-8.0.0-RC5/webapps/spring-app.war
Failed to instantiate SLF4J LoggerFactory
Reported exception:
java.lang.NoClassDefFoundError: org/slf4j/spi/LoggerFactoryBinder
        at java.lang.ClassLoader.defineClass1(Native Method)
        at java.lang.ClassLoader.defineClass(ClassLoader.java:800)
        at java.security.SecureClassLoader.defineClass(SecureClassLoader.java:142)
        at java.net.URLClassLoader.defineClass(URLClassLoader.java:449)
        at java.net.URLClassLoader.access$100(URLClassLoader.java:71)
        at java.net.URLClassLoader$1.run(URLClassLoader.java:361)
        at java.net.URLClassLoader$1.run(URLClassLoader.java:355)
        at java.security.AccessController.doPrivileged(Native Method)
        at java.net.URLClassLoader.findClass(URLClassLoader.java:354)
        at java.lang.ClassLoader.loadClass(ClassLoader.java:425)
        at java.lang.ClassLoader.loadClass(ClassLoader.java:358)
        at java.lang.Class.forName0(Native Method)
        at java.lang.Class.forName(Class.java:270)
        at org.apache.catalina.loader.WebappClassLoader.loadClass(WebappClassLoader.java:1562)
        at org.apache.catalina.loader.WebappClassLoader.loadClass(WebappClassLoader.java:1420)
        at org.slf4j.LoggerFactory.bind(LoggerFactory.java:129)
        at org.slf4j.LoggerFactory.performInitialization(LoggerFactory.java:108)
        at org.slf4j.LoggerFactory.getILoggerFactory(LoggerFactory.java:302)
        at org.slf4j.LoggerFactory.getLogger(LoggerFactory.java:276)
        at org.apache.commons.logging.impl.SLF4JLogFactory.getInstance(SLF4JLogFactory.java:156)
        at org.apache.commons.logging.impl.SLF4JLogFactory.getInstance(SLF4JLogFactory.java:132)
        at org.apache.commons.logging.LogFactory.getLog(LogFactory.java:274)
        at org.springframework.web.context.ContextLoader.initWebApplicationContext(ContextLoader.java:282)
        at org.springframework.web.context.ContextLoaderListener.contextInitialized(ContextLoaderListener.java:106)
        at org.apache.catalina.core.StandardContext.listenerStart(StandardContext.java:4830)
        at org.apache.catalina.core.StandardContext.startInternal(StandardContext.java:5276)
        at org.apache.catalina.util.LifecycleBase.start(LifecycleBase.java:150)
        at org.apache.catalina.core.ContainerBase.addChildInternal(ContainerBase.java:726)
        at org.apache.catalina.core.ContainerBase.addChild(ContainerBase.java:702)
        at org.apache.catalina.core.StandardHost.addChild(StandardHost.java:698)
        at org.apache.catalina.startup.HostConfig.deployWAR(HostConfig.java:968)
        at org.apache.catalina.startup.HostConfig$DeployWar.run(HostConfig.java:1742)
        at java.util.concurrent.Executors$RunnableAdapter.call(Executors.java:471)
        at java.util.concurrent.FutureTask.run(FutureTask.java:262)
        at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1145)
        at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:615)
        at java.lang.Thread.run(Thread.java:744)
Caused by: java.lang.ClassNotFoundException: org.slf4j.spi.LoggerFactoryBinder
        at java.net.URLClassLoader$1.run(URLClassLoader.java:366)
        at java.net.URLClassLoader$1.run(URLClassLoader.java:355)
        at java.security.AccessController.doPrivileged(Native Method)
        at java.net.URLClassLoader.findClass(URLClassLoader.java:354)
        at java.lang.ClassLoader.loadClass(ClassLoader.java:425)
        at java.lang.ClassLoader.loadClass(ClassLoader.java:358)
        ... 37 more

这没有任何意义，因为我确实在 web-app/WEB-INF/lib/slf4j-api-1.7.6.jar 中有 org.slf4j.spi.LoggerFactoryBinder，这在昨天也有效，但突然无法启动网络应用程序。

是什么原因造成的？
如何在一开始就在 Tomcat 中检查/调试 Web 应用程序的类路径？

Answer 1

您说 slf4j API jar 是（曾经）Web 应用程序的一部分。我猜你的 slf4j binding jar 是（曾经）安装在 Tomcat 的 lib 目录或一些不是 Web 应用程序私有的地方。这似乎应该是使用 Slf4j 的一种自然方式——Web 应用程序自带 API jar，而 tomcat 安装提供了正确的绑定。不幸的是，这不起作用。

请参阅Tomcat classloader how-to。当以这种方式部署 Slf4j 时，API jar 使用 web 应用程序的私有类加载器加载，而绑定 jar 使用“通用”类加载器或其他通用类加载器之一加载。 webapp类加载器中的类可以从common loader加载类，但是common loader中的类不能访问webapp loader。

具体来说，当 API jar 中的类尝试加载绑定 jar 中的类时，您的异常会发生，即org.slf4j.impl.StaticLoggerBinder。您在 Web 应用程序中的代码能够访问 API jar，并且 API jar 能够在绑定 jar 中找到此类。但是，StaticLoggingBinder 引用了 API jar 中的 org.slf4j.spi.LoggerFactoryBinder。绑定 jar 中的类无法访问 webapp 类加载器，因此无法加载该类并且您会收到异常。

不幸的是，唯一直接的解决方案是将 Slf4j API 和绑定 jar 部署在同一个“位置”。它们都应该是 Web 应用程序私有类的一部分，或者都是通用 Tomcat 类的一部分。

Answer 2

如果您使用 catalina.sh（或 .bat）脚本（由 startup.sh 和 shutdown.sh 使用）运行 Tomcat，那么您可以修改 JAVA_OPTS 变量以包含“-verbose:class”转变。这将导致加载的类的信息打印到标准输出

关于你的问题，我感觉可能有一些旧版本的 jar 可能会发生冲突