今天项目启动时报错，刻意记录一下，具体报错部分日志如下：

Caused by: org.springframework.beans.factory.BeanCreationException: Error creating bean with name 'sqlSessionFactory' defined in class path resource [com/baomidou/mybatisplus/autoconfigure/MybatisPlusAutoConfiguration.class]: Bean instantiation via factory method failed; nested exception is org.springframework.beans.BeanInstantiationException: Failed to instantiate [org.apache.ibatis.session.SqlSessionFactory]: Factory method 'sqlSessionFactory' threw exception; nested exception is java.lang.NoClassDefFoundError: org/mybatis/logging/LoggerFactoryat org.springframework.beans.factory.support.ConstructorResolver.instantiate(ConstructorResolver.java:658) ~[spring-beans-5.3.12.jar:5.3.12]at org.springframework.beans.factory.support.ConstructorResolver.instantiateUsingFactoryMethod(ConstructorResolver.java:638) ~[spring-beans-5.3.12.jar:5.3.12]at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.instantiateUsingFactoryMethod(AbstractAutowireCapableBeanFactory.java:1352) ~[spring-beans-5.3.12.jar:5.3.12]at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.createBeanInstance(AbstractAutowireCapableBeanFactory.java:1195) ~[spring-beans-5.3.12.jar:5.3.12]at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.doCreateBean(AbstractAutowireCapableBeanFactory.java:582) ~[spring-beans-5.3.12.jar:5.3.12]at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.createBean(AbstractAutowireCapableBeanFactory.java:542) ~[spring-beans-5.3.12.jar:5.3.12]at org.springframework.beans.factory.support.AbstractBeanFactory.lambda$doGetBean$0(AbstractBeanFactory.java:335) ~[spring-beans-5.3.12.jar:5.3.12]at org.springframework.beans.factory.support.DefaultSingletonBeanRegistry.getSingleton(DefaultSingletonBeanRegistry.java:234) ~[spring-beans-5.3.12.jar:5.3.12]at org.springframework.beans.factory.support.AbstractBeanFactory.doGetBean(AbstractBeanFactory.java:333) ~[spring-beans-5.3.12.jar:5.3.12]at org.springframework.beans.factory.support.AbstractBeanFactory.getBean(AbstractBeanFactory.java:208) ~[spring-beans-5.3.12.jar:5.3.12]at org.springframework.beans.factory.config.DependencyDescriptor.resolveCandidate(DependencyDescriptor.java:276) ~[spring-beans-5.3.12.jar:5.3.12]at org.springframework.beans.factory.support.DefaultListableBeanFactory.doResolveDependency(DefaultListableBeanFactory.java:1380) ~[spring-beans-5.3.12.jar:5.3.12]at org.springframework.beans.factory.support.DefaultListableBeanFactory.resolveDependency(DefaultListableBeanFactory.java:1300) ~[spring-beans-5.3.12.jar:5.3.12]at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.autowireByType(AbstractAutowireCapableBeanFactory.java:1519) ~[spring-beans-5.3.12.jar:5.3.12]... 83 common frames omitted
Caused by: org.springframework.beans.BeanInstantiationException: Failed to instantiate [org.apache.ibatis.session.SqlSessionFactory]: Factory method 'sqlSessionFactory' threw exception; nested exception is java.lang.NoClassDefFoundError: org/mybatis/logging/LoggerFactoryat org.springframework.beans.factory.support.SimpleInstantiationStrategy.instantiate(SimpleInstantiationStrategy.java:185) ~[spring-beans-5.3.12.jar:5.3.12]at org.springframework.beans.factory.support.ConstructorResolver.instantiate(ConstructorResolver.java:653) ~[spring-beans-5.3.12.jar:5.3.12]... 96 common frames omitted
Caused by: java.lang.NoClassDefFoundError: org/mybatis/logging/LoggerFactoryat com.baomidou.mybatisplus.extension.spring.MybatisSqlSessionFactoryBean.<clinit>(MybatisSqlSessionFactoryBean.java:93) ~[mybatis-plus-extension-3.4.1.jar:3.4.1]at com.baomidou.mybatisplus.autoconfigure.MybatisPlusAutoConfiguration.sqlSessionFactory(MybatisPlusAutoConfiguration.java:160) ~[mybatis-plus-boot-starter-3.4.1.jar:3.4.1]at com.baomidou.mybatisplus.autoconfigure.MybatisPlusAutoConfiguration$$EnhancerBySpringCGLIB$$6872e5b0.CGLIB$sqlSessionFactory$1(<generated>) ~[mybatis-plus-boot-starter-3.4.1.jar:3.4.1]at com.baomidou.mybatisplus.autoconfigure.MybatisPlusAutoConfiguration$$EnhancerBySpringCGLIB$$6872e5b0$$FastClassBySpringCGLIB$$3600565f.invoke(<generated>) ~[mybatis-plus-boot-starter-3.4.1.jar:3.4.1]at org.springframework.cglib.proxy.MethodProxy.invokeSuper(MethodProxy.java:244) ~[spring-core-5.3.12.jar:5.3.12]at org.springframework.context.annotation.ConfigurationClassEnhancer$BeanMethodInterceptor.intercept(ConfigurationClassEnhancer.java:331) ~[spring-context-5.3.12.jar:5.3.12]at com.baomidou.mybatisplus.autoconfigure.MybatisPlusAutoConfiguration$$EnhancerBySpringCGLIB$$6872e5b0.sqlSessionFactory(<generated>) ~[mybatis-plus-boot-starter-3.4.1.jar:3.4.1]at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method) ~[na:1.8.0_331]at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:62) ~[na:1.8.0_331]at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43) ~[na:1.8.0_331]at java.lang.reflect.Method.invoke(Method.java:498) ~[na:1.8.0_331]at org.springframework.beans.factory.support.SimpleInstantiationStrategy.instantiate(SimpleInstantiationStrategy.java:154) ~[spring-beans-5.3.12.jar:5.3.12]... 97 common frames omitted
Caused by: java.lang.ClassNotFoundException: org.mybatis.logging.LoggerFactoryat java.net.URLClassLoader.findClass(URLClassLoader.java:387) ~[na:1.8.0_331]at java.lang.ClassLoader.loadClass(ClassLoader.java:418) ~[na:1.8.0_331]at sun.misc.Launcher$AppClassLoader.loadClass(Launcher.java:355) ~[na:1.8.0_331]at java.lang.ClassLoader.loadClass(ClassLoader.java:351) ~[na:1.8.0_331]... 109 common frames omitted

        刚看到日志，第一时间感觉是缺少mybatis日志依赖导致，可以不管怎么折腾始终没能解决问题，后来才发现这个原因是Mybatis和Mybatis Plus依赖同时存在导致的！！！

        那么问题就简单得多了，既然mybatis plus里面包含了mybatis，那么我直接把mybatis去掉不就完了吗，事实证明这是可以的，去掉下面的依赖（mybatis-spring-boot-starter）：

        <dependency><groupId>org.mybatis.spring.boot</groupId><artifactId>mybatis-spring-boot-starter</artifactId><version>1.3.1</version></dependency>

        此时，再次启动项目，正常启动成功了！