java - SpringBoot can run in Eclipse, but there will be a logback exception when deployed on Tomcat8.

Question

To develop a new project, I used Springboot as the framework. During the project development, I have been using Eclipse for testing. Everything was normal. I discovered this problem recently when I was preparing to deploy it to the local Tomcat8 for client development. ,The specific exception is as follows:

23-May-2017 14:32:20.119 严重 [localhost-startStop-1] org.apache.catalina.core.ContainerBase.addChildInternal ContainerBase.addChild: start: 
 org.apache.catalina.LifecycleException: Failed to start component [StandardEngine[Catalina].StandardHost[localhost].StandardContext[/ucwapi]]
    at org.apache.catalina.util.LifecycleBase.start(LifecycleBase.java:167)
    at org.apache.catalina.core.ContainerBase.addChildInternal(ContainerBase.java:752)
    at org.apache.catalina.core.ContainerBase.addChild(ContainerBase.java:728)
    at org.apache.catalina.core.StandardHost.addChild(StandardHost.java:734)
    at org.apache.catalina.startup.HostConfig.deployWAR(HostConfig.java:952)
    at org.apache.catalina.startup.HostConfig$DeployWar.run(HostConfig.java:1823)
    at java.util.concurrent.Executors$RunnableAdapter.call(Executors.java:511)
    at java.util.concurrent.FutureTask.run(FutureTask.java:266)
    at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1142)
    at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:617)
    at java.lang.Thread.run(Thread.java:745)
Caused by: java.lang.IllegalArgumentException: LoggerFactory is not a Logback LoggerContext but Logback is on the classpath. Either remove Logback or the competing implementation (class org.apache.logging.slf4j.Log4jLoggerFactory loaded from file:/C:/server/apache-tomcat-8.5.15/webapps/ucwapi/WEB-INF/lib/log4j-slf4j-impl-2.4.1.jar). If you are using WebLogic you will need to add 'org.slf4j' to prefer-application-packages in WEB-INF/weblogic.xml Object of class [org.apache.logging.slf4j.Log4jLoggerFactory] must be an instance of class ch.qos.logback.classic.LoggerContext
    at org.springframework.util.Assert.isInstanceOf(Assert.java:346)
    at org.springframework.boot.logging.logback.LogbackLoggingSystem.getLoggerContext(LogbackLoggingSystem.java:221)
    at org.springframework.boot.logging.logback.LogbackLoggingSystem.getLogger(LogbackLoggingSystem.java:213)
    at org.springframework.boot.logging.logback.LogbackLoggingSystem.beforeInitialize(LogbackLoggingSystem.java:98)
    at org.springframework.boot.logging.LoggingApplicationListener.onApplicationStartedEvent(LoggingApplicationListener.java:215)
    at org.springframework.boot.logging.LoggingApplicationListener.onApplicationEvent(LoggingApplicationListener.java:197)
    at org.springframework.context.event.SimpleApplicationEventMulticaster.invokeListener(SimpleApplicationEventMulticaster.java:166)
    at org.springframework.context.event.SimpleApplicationEventMulticaster.multicastEvent(SimpleApplicationEventMulticaster.java:138)
    at org.springframework.context.event.SimpleApplicationEventMulticaster.multicastEvent(SimpleApplicationEventMulticaster.java:121)
    at org.springframework.boot.context.event.EventPublishingRunListener.publishEvent(EventPublishingRunListener.java:111)
    at org.springframework.boot.context.event.EventPublishingRunListener.started(EventPublishingRunListener.java:60)
    at org.springframework.boot.SpringApplicationRunListeners.started(SpringApplicationRunListeners.java:48)
    at org.springframework.boot.SpringApplication.run(SpringApplication.java:303)
    at org.springframework.boot.context.web.SpringBootServletInitializer.run(SpringBootServletInitializer.java:149)
    at org.springframework.boot.context.web.SpringBootServletInitializer.createRootApplicationContext(SpringBootServletInitializer.java:129)
    at org.springframework.boot.context.web.SpringBootServletInitializer.onStartup(SpringBootServletInitializer.java:85)
    at org.springframework.web.SpringServletContainerInitializer.onStartup(SpringServletContainerInitializer.java:169)
    at org.apache.catalina.core.StandardContext.startInternal(StandardContext.java:5196)
    at org.apache.catalina.util.LifecycleBase.start(LifecycleBase.java:150)
    ... 10 more

23-May-2017 14:32:20.120 严重 [localhost-startStop-1] org.apache.catalina.startup.HostConfig.deployWAR Error deploying web application archive [C:\server\apache-tomcat-8.5.15\webapps\ucwapi.war]
 java.lang.IllegalStateException: ContainerBase.addChild: start: org.apache.catalina.LifecycleException: Failed to start component [StandardEngine[Catalina].StandardHost[localhost].StandardContext[/ucwapi]]
    at org.apache.catalina.core.ContainerBase.addChildInternal(ContainerBase.java:756)
    at org.apache.catalina.core.ContainerBase.addChild(ContainerBase.java:728)
    at org.apache.catalina.core.StandardHost.addChild(StandardHost.java:734)
    at org.apache.catalina.startup.HostConfig.deployWAR(HostConfig.java:952)
    at org.apache.catalina.startup.HostConfig$DeployWar.run(HostConfig.java:1823)
    at java.util.concurrent.Executors$RunnableAdapter.call(Executors.java:511)
    at java.util.concurrent.FutureTask.run(FutureTask.java:266)
    at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1142)
    at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:617)
    at java.lang.Thread.run(Thread.java:745)

Springboot version is 1.3.5
logback version is 1.1.7

Answer 1

Tomcat7.0 upgraded to 8.0 problem solved

Answer 2

Can I run war locally?

Answer 3

Reason: The relationship between ClassLoader, the ClassLoader implementation in the IDE is different from the Spring Boot JarLauncher, therefore, different jars are loaded. log4j-slf4j and logback are both implementations of slf4j-api, so they conflict.

Solution: Remove log4j-slf4j dependency (via Maven)