SpringBoot结合MybatisPlus启动报错：BeanNotOfRequiredTypeException

 报错信息：

详细报错信息如下：

 org.springframework.beans.factory.BeanNotOfRequiredTypeException: Bean named 'ddlApplicationRunner' is expected to be of type 'org.springframework.boot.Runner' but was actually of type 'org.springframework.beans.factory.support.NullBean'

at org.springframework.beans.factory.support.AbstractBeanFactory.adaptBeanInstance(AbstractBeanFactory.java:410) ~[spring-beans-6.1.2.jar:6.1.2]
    at org.springframework.beans.factory.support.AbstractBeanFactory.doGetBean(AbstractBeanFactory.java:391) ~[spring-beans-6.1.2.jar:6.1.2]
    at org.springframework.beans.factory.support.AbstractBeanFactory.getBean(AbstractBeanFactory.java:204) ~[spring-beans-6.1.2.jar:6.1.2]
    at org.springframework.boot.SpringApplication.callRunners(SpringApplication.java:778) ~[spring-boot-3.2.1.jar:3.2.1]
    at org.springframework.boot.SpringApplication.run(SpringApplication.java:341) ~[spring-boot-3.2.1.jar:3.2.1]
    at org.springframework.boot.SpringApplication.run(SpringApplication.java:1358) ~[spring-boot-3.2.1.jar:3.2.1]
    at org.springframework.boot.SpringApplication.run(SpringApplication.java:1347) ~[spring-boot-3.2.1.jar:3.2.1]
    at com.zdd.chap5b.Chap5bApplication.main(Chap5bApplication.java:10) ~[classes/:na]
    at java.base/jdk.internal.reflect.NativeMethodAccessorImpl.invoke0(Native Method) ~[na:na]
    at java.base/jdk.internal.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:77) ~[na:na]
    at java.base/jdk.internal.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43) ~[na:na]
    at java.base/java.lang.reflect.Method.invoke(Method.java:568) ~[na:na]
    at org.springframework.boot.devtools.restart.RestartLauncher.run(RestartLauncher.java:50) ~[spring-boot-devtools-3.2.1.jar:3.2.1]

解决方案：

这个错误找了很久，觉得自己代码没错，后面看到了这一篇文章！

http://t.csdnimg.cn/QSYTy

发现是由于版本迭代造成的问题，后面我将pom.xml中引入的mybatis-plus依赖版本修改为3.5.5，然后重启就好了！

  
            com.baomidou
            mybatis-plus-boot-starter
            3.5.5