今天写代码的时候突然出现了这个错误：Invalid bean definition with name ‘userMapper’ defined in file [D:\com\frontend\mapper\UserMapper.class]: Invalid value type for attribute ‘factoryBeanObjectType’: java.lang.String

并且，在代码中目前只写了一个mapper，网上的办法试了很多，都不行，最后发现是mybatis-plus-boot-starter版本的问题，然后将3.5.7改成了3.4.1，新的问题又出现了：Unsatisfied dependency expressed through field ‘userService’: Error creating bean with name ‘userServiceImpl’: Unsatisfied dependency expressed through field ‘baseMapper’: No qualifying bean of type ‘com.frontend.pusharticle.mapper.UserMapper’ available: expected at least 1 bean which qualifies as autowire candidate. Dependency annotations: {@org.springframework.beans.factory.annotation.Autowired(required=true)}
又找了很多资料，试了很多方法发现还是mybatis-plus-boot-starter的问题，最后修改为：

<dependency>
	<groupId>com.baomidou</groupId>
	<artifactId>mybatis-plus-spring-boot3-starter</artifactId>
	<version>3.5.7</version>
</dependency>

这次没问题了