错误： Failed to introspect Class [com.baomidou.mybatisplus.autoconfiguration] from ClassLoader

在用IDEA创建SpringBoot+mybatis-plus项目时，启动时报错。
#具体错误如下

java.lang.IllegalStateException: Failed to introspect Class [com.baomidou.mybatisplus.autoconfigure.MybatisPlusAutoConfiguration] from ClassLoader [sun.misc.Launcher$AppClassLoader@18b4aac2]
	at org.springframework.util.ReflectionUtils.getDeclaredMethods(ReflectionUtils.java:686) ~[spring-core-5.1.5.RELEASE.jar:5.1.5.RELEASE]
	at org.springframework.util.ReflectionUtils.doWithMethods(ReflectionUtils.java:583) ~[spring-core-5.1.5.RELEASE.jar:5.1.5.RELEASE]
	at org.springframework.util.ReflectionUtils.doWithMethods(ReflectionUtils.java:568) ~[spring-core-5.1.5.RELEASE.jar:5.1.5.RELEASE]
	at org.springframework.util.ReflectionUtils.getUniqueDeclaredMethods(ReflectionUtils.java:626) ~[spring-core-5.1.5.RELEASE.jar:5.1.5.RELEASE]
	at java.util.concurrent.ConcurrentHashMap.computeIfAbsent(ConcurrentHashMap.java:1660) ~[na:1.8.0_121]
	at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.getTypeForFactoryMethod(AbstractAutowireCapableBeanFactory.java:738) ~[spring-beans-5.1.5.RELEASE.jar:5.1.5.RELEASE]
	at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.determineTargetType(AbstractAutowireCapableBeanFactory.java:679) ~[spring-beans-5.1.5.RELEASE.jar:5.1.5.RELEASE]
	at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.predictBeanType(AbstractAutowireCapableBeanFactory.java:647) ~[spring-beans-5.1.5.RELEASE.jar:5.1.5.RELEASE]
	at org.springframework.beans.factory.support.AbstractBeanFactory.isFactoryBean(AbstractBeanFactory.java:1518) ~[spring-beans-5.1.5.RELEASE.jar:5.1.5.RELEASE]
	at org.springframework.beans.factory.support.DefaultListableBeanFactory.doGetBeanNamesForType(DefaultListableBeanFactory.java:507) ~[spring-beans-5.1.5.RELEASE.jar:5.1.5.RELEASE]
	at org.springframework.beans.factory.support.DefaultListableBeanFactory.getBeanNamesForType(DefaultListableBeanFactory.java:477) ~[spring-beans-5.1.5.RELEASE.jar:5.1.5.RELEASE]
	at org.springframework.beans.factory.support.DefaultListableBeanFactory.getBeansOfType(DefaultListableBeanFactory.java:598) ~[spring-beans-5.1.5.RELEASE.jar:5.1.5.RELEASE]
	at org.springframework.beans.factory.support.DefaultListableBeanFactory.getBeansOfType(DefaultListableBeanFactory.java:590) ~[spring-beans-5.1.5.RELEASE.jar:5.1.5.RELEASE]
	at org.springframework.context.support.AbstractApplicationContext.getBeansOfType(AbstractApplicationContext.java:1226) ~[spring-context-5.1.5.RELEASE.jar:5.1.5.RELEASE]
	at org.springframework.boot.SpringApplication.getExitCodeFromMappedException(SpringApplication.java:905) [spring-boot-2.1.3.RELEASE.jar:2.1.3.RELEASE]
	at org.springframework.boot.SpringApplication.getExitCodeFromException(SpringApplication.java:891) [spring-boot-2.1.3.RELEASE.jar:2.1.3.RELEASE]
	at org.springframework.boot.SpringApplication.handleExitCode(SpringApplication.java:877) [spring-boot-2.1.3.RELEASE.jar:2.1.3.RELEASE]
	at org.springframework.boot.SpringApplication.handleRunFailure(SpringApplication.java:826) [spring-boot-2.1.3.RELEASE.jar:2.1.3.RELEASE]
	at org.springframework.boot.SpringApplication.run(SpringApplication.java:327) [spring-boot-2.1.3.RELEASE.jar:2.1.3.RELEASE]
	at org.springframework.boot.SpringApplication.run(SpringApplication.java:1260) [spring-boot-2.1.3.RELEASE.jar:2.1.3.RELEASE]
	at org.springframework.boot.SpringApplication.run(SpringApplication.java:1248) [spring-boot-2.1.3.RELEASE.jar:2.1.3.RELEASE]
	at com.example.demo.SpringbootDemoApplication.main(SpringbootDemoApplication.java:10) [classes/:na]
Caused by: java.lang.NoClassDefFoundError: com/baomidou/mybatisplus/extension/spring/MybatisSqlSessionFactoryBean
	at java.lang.Class.getDeclaredMethods0(Native Method) ~[na:1.8.0_121]
	at java.lang.Class.privateGetDeclaredMethods(Class.java:2701) ~[na:1.8.0_121]
	at java.lang.Class.getDeclaredMethods(Class.java:1975) ~[na:1.8.0_121]
	at org.springframework.util.ReflectionUtils.getDeclaredMethods(ReflectionUtils.java:668) ~[spring-core-5.1.5.RELEASE.jar:5.1.5.RELEASE]
	... 21 common frames omitted
Caused by: java.lang.ClassNotFoundException: com.baomidou.mybatisplus.extension.spring.MybatisSqlSessionFactoryBean
	at java.net.URLClassLoader.findClass(URLClassLoader.java:381) ~[na:1.8.0_121]
	at java.lang.ClassLoader.loadClass(ClassLoader.java:424) ~[na:1.8.0_121]
	at sun.misc.Launcher$AppClassLoader.loadClass(Launcher.java:331) ~[na:1.8.0_121]
	at java.lang.ClassLoader.loadClass(ClassLoader.java:357) ~[na:1.8.0_121]
	... 25 common frames omitted

求解