SpringBoot 启动后输出：
DEBUG StatusLogger org.slf4j.helpers.Log4jLoggerFactory is not on classpath. Good! SLF4J: Class path contains multiple SLF4J bindings. SLF4J: Found binding in [jar:file:/C:/Users/xxx/.m2/repository/ch/qos/logback/logback-classic/1.2.3/logback-classic-1.2.3.jar!/org/slf4j/impl/StaticLoggerBinder.class] SLF4J: Found binding in [jar:file:/C:/Users/xxx/.m2/repository/org/slf4j/slf4j-simple/1.7.25/slf4j-simple-1.7.25.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 [ch.qos.logback.classic.util.ContextSelectorStaticBinder]
系统能正常正常启动，这个提示是因为存在多个日志实现绑定，即：
(1) logback-classic-1.2.3.jar
(2) slf4j-simple-1.7.25.jar
【SLF4j ： Simple Logging Facade for Java (SLF4J)，目前用的比较多的日志门面，类似commons-log库】
SpringBoot默认用的logback，那就把slf4j-simple给禁用掉。可以通过idea的查找依赖关系或mvn dependency:tree 来找到依赖
最后发现是j2cache依赖了slf4j-simple
<dependency> <groupId>net.oschina.j2cache</groupId> <artifactId>j2cache-core</artifactId> <version>2.7.2-release</version> <exclusions> <exclusion> <groupId>org.slf4j</groupId> <artifactId>slf4j-simple</artifactId> </exclusion> </exclusions> </dependency>
增加排除，问题解决。
SLF4J: Class path contains multiple SLF4J bindings 问题解决
原文：https://www.cnblogs.com/webjlwang/p/14616650.html