SpringBoot启动：LoggerFactory is not a Logback LoggerContext but Logback is on the classpath

报错信息： 

SLF4J: Class path contains multiple SLF4J bindings.
SLF4J: Found binding in [jar:file:/C:/Users/.m2/repository/org/slf4j/slf4j-log4j12/1.7.25/slf4j-log4j12-1.7.25.jar!/org/slf4j/impl/StaticLoggerBinder.class]
SLF4J: Found binding in [jar:file:/C:/Users/.m2/repository/ch/qos/logback/logback-classic/1.2.3/logback-classic-1.2.3.jar!/org/slf4j/impl/StaticLoggerBinder.class]
SLF4J: See http://www.slf4j.org/codes.html#multiple_bindings for an explanation.
SLF4J: Actual binding is of type [org.slf4j.impl.Log4jLoggerFactory]
Exception in thread "main" java.lang.IllegalArgumentException: LoggerFactory is not a Logback LoggerContext but Logback is on the classpath. Either remove Logback or the competing implementation (class org.slf4j.impl.Log4jLoggerFactory loaded from file:/C:/Users/zhanggong004/.m2/repository/org/slf4j/slf4j-log4j12/1.7.25/slf4j-log4j12-1.7.25.jar). If you are using WebLogic you will need to add 'org.slf4j' to prefer-application-packages in WEB-INF/weblogic.xml: org.slf4j.impl.Log4jLoggerFactory
	at org.springframework.util.Assert.instanceCheckFailed(Assert.java:655)
	at org.springframework.util.Assert.isInstanceOf(Assert.java:555)
	at org.springframework.boot.logging.logback.LogbackLoggingSystem.getLoggerContext(LogbackLoggingSystem.java:286)
	at org.springframework.boot.logging.logback.LogbackLoggingSystem.beforeInitialize(LogbackLoggingSystem.java:102)
	at org.springframework.boot.context.logging.LoggingApplicationListener.onApplicationStartingEvent(LoggingApplicationListener.java:220)
	at org.springframework.boot.context.logging.LoggingApplicationListener.onApplicationEvent(LoggingApplicationListener.java:199)
	at org.springframework.context.event.SimpleApplicationEventMulticaster.doInvokeListener(SimpleApplicationEventMulticaster.java:172)
	at org.springframework.context.event.SimpleApplicationEventMulticaster.invokeListener(SimpleApplicationEventMulticaster.java:165)
	at org.springframework.context.event.SimpleApplicationEventMulticaster.multicastEvent(SimpleApplicationEventMulticaster.java:139)
	at org.springframework.context.event.SimpleApplicationEventMulticaster.multicastEvent(SimpleApplicationEventMulticaster.java:127)
	at org.springframework.boot.context.event.EventPublishingRunListener.starting(EventPublishingRunListener.java:69)
	at org.springframework.boot.SpringApplicationRunListeners.starting(SpringApplicationRunListeners.java:48)
	at org.springframework.boot.SpringApplication.run(SpringApplication.java:302)
	at org.springframework.boot.SpringApplication.run(SpringApplication.java:1260)
	at org.springframework.boot.SpringApplication.run(SpringApplication.java:1248)
	at com.example.dubboconsumer.DubboConsumerApplication.main(DubboConsumerApplication.java:13)

第一种情况：看到这个报错，第一反应是slf4j包冲突。

解决：对相应的包进行排除，如

     org.springframework.boot
     spring-boot-starter-web
     
          
               org.slf4j
               slf4j-log4j12
          
     




   ch.qos.logback
   logback-classic
   1.2.3

第二种情况：是 SpringBoot 加载顺序的问题，在SpringBoot项目里面，日志的绑定顺序有严格要求。

解决：调整SpringBoot相关pom.xml文件，将引入的SpringBoot配置文件放在最前，如：

 
        
            org.springframework.boot
            spring-boot-starter-web
        
        
        
            org.springframework.cloud
            spring-cloud-starter-zookeeper-discovery
            
            
                
                    org.apache.zookeeper
                    zookeeper
                
            
        
        
        
            org.apache.zookeeper
            zookeeper
            3.4.9
        

我遇到的是第二种情况，把spring-boot-starter-web包调到最前面，项目正常启动。