我正在使用 Tomcat 部署一个 java webapp。
我得到一个很长的堆栈跟踪,简而言之:
GRAVE: A child container failed during start
java.util.concurrent.ExecutionException: org.apache.catalina.LifecycleException: Failed to start component [StandardEngine[Catalina].StandardHost[localhost].StandardContext[/new-webapp]]
[...]
Caused by: java.lang.NoClassDefFoundError: Lorg/apache/logging/log4j/Logger;
at java.lang.Class.getDeclaredFields0(Native Method)
at java.lang.Class.privateGetDeclaredFields(Class.java:2509)
at java.lang.Class.getDeclaredFields(Class.java:1819)
at org.apache.catalina.util.Introspection.getDeclaredFields(Introspection.java:106)
at org.apache.catalina.startup.WebAnnotationSet.loadFieldsAnnotation(WebAnnotationSet.java:256)
at org.apache.catalina.startup.WebAnnotationSet.loadApplicationFilterAnnotations(WebAnnotationSet.java:105)
at org.apache.catalina.startup.WebAnnotationSet.loadApplicationAnnotations(WebAnnotationSet.java:64)
at org.apache.catalina.startup.ContextConfig.applicationAnnotationsConfig(ContextConfig.java:335)
at org.apache.catalina.startup.ContextConfig.configureStart(ContextConfig.java:782)
at org.apache.catalina.startup.ContextConfig.lifecycleEvent(ContextConfig.java:306)
at org.apache.catalina.util.LifecycleSupport.fireLifecycleEvent(LifecycleSupport.java:95)
at org.apache.catalina.util.LifecycleBase.fireLifecycleEvent(LifecycleBase.java:90)
at org.apache.catalina.core.StandardContext.startInternal(StandardContext.java:5150)
at org.apache.catalina.util.LifecycleBase.start(LifecycleBase.java:147)
... 6 more
Caused by: java.lang.ClassNotFoundException: org.apache.logging.log4j.Logger
at org.apache.catalina.loader.WebappClassLoaderBase.loadClass(WebappClassLoaderBase.java:1305)
at org.apache.catalina.loader.WebappClassLoaderBase.loadClass(WebappClassLoaderBase.java:1139)
... 20 more
[...]
现在,错误很明显了。由于某种原因,log4j 包不在类路径中。
该应用程序是一个maven webapp,pom.xml是这样的:
<project
xmlns="http://maven.apache.org/POM/4.0.0"
xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/maven-v4_0_0.xsd">
<modelVersion>4.0.0</modelVersion>
<groupId>com.wb</groupId>
<artifactId>new-webapp</artifactId>
<packaging>war</packaging>
<version>0.0.1</version>
<properties>
<log4j.version>2.5</log4j.version>
</properties>
<dependencies>
[...]
<!-- Logging -->
<dependency>
<groupId>org.apache.logging.log4j</groupId>
<artifactId>log4j-api</artifactId>
<version>${log4j.version}</version>
</dependency>
<dependency>
<groupId>org.apache.logging.log4j</groupId>
<artifactId>log4j-core</artifactId>
<version>${log4j.version}</version>
</dependency>
<dependency>
<groupId>org.apache.logging.log4j</groupId>
<artifactId>log4j-web</artifactId>
<version>${log4j.version}</version>
</dependency>
</dependencies>
[...]
</project>
如果我转到项目属性,在 Libraries->Maven Dependencies 下,我会看到:
找到并下载了库,它们位于类路径中。
我还尝试在我的项目中打开一个 java 类并声明
org.apache.logging.log4j.Logger Logger;
没有错误,找到了 Logger
接口。
这里发生了什么?为什么即使库在类路径中,Tomcat 也无法启动?
编辑 - 这是 log4j 配置文件:
<?xml version="1.0" encoding="UTF-8"?>
<Configuration status="INFO">
<Appenders>
<Console name="Console" target="SYSTEM_OUT">
<PatternLayout pattern="%d{HH:mm:ss.SSS} [%t] %-5level %logger{36} - %msg%n" />
</Console>
</Appenders>
<Loggers>
<Root level="INFO">
<AppenderRef ref="Console" />
</Root>
</Loggers>
</Configuration>
原文由 BackSlash 发布,翻译遵循 CC BY-SA 4.0 许可协议
根据您所做的描述,我假设您正在使用 Eclipse。
那么,您最好转到
Project properties
->Deployment assembly
并确保包含maven dependencies
条目。我经常尝试在执行
Maven
->Update Project
时丢失此配置。