Spring Boot & MyBatis Plus 版本兼容问题（记录）

问题描述

当使用 spring-boot-starter-parent v3.2.0 以上版本；mybatis-plus-boot-starter 3.5.10 时，如：

<parent>
	<groupId>org.springframework.boot</groupId>
	<artifactId>spring-boot-starter-parent</artifactId>
	<version>3.2.0</version>
	<relativePath/> <!-- lookup parent from repository -->
</parent>

<dependency>
	<groupId>com.baomidou</groupId>
	<artifactId>mybatis-plus-boot-starter</artifactId>
	<version>3.5.10</version>
</dependency>

会出现以下错误：

Invalid value type for attribute 'factoryBeanObjectType': java.lang.String

错误详情：

org.springframework.beans.factory.BeanDefinitionStoreException: Invalid bean definition with name 'userMapper' defined in file [/Volumes/Macintosh/Workspace/Michael/michael-spica-mybatis-plus/target/classes/michael/spica/mybatis/plus/mapper/UserMapper.class]: Invalid value type for attribute 'factoryBeanObjectType': java.lang.String
	at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.getTypeForFactoryBean(AbstractAutowireCapableBeanFactory.java:858) ~[spring-beans-6.2.1.jar:6.2.1]
	at org.springframework.beans.factory.support.AbstractBeanFactory.getType(AbstractBeanFactory.java:742) ~[spring-beans-6.2.1.jar:6.2.1]
	at org.springframework.beans.factory.support.DefaultListableBeanFactory.findAnnotationOnBean(DefaultListableBeanFactory.java:765) ~[spring-beans-6.2.1.jar:6.2.1]
	at org.springframework.boot.sql.init.dependency.AnnotationDependsOnDatabaseInitializationDetector.detect(AnnotationDependsOnDatabaseInitializationDetector.java:36) ~[spring-boot-3.4.1.jar:3.4.1]
	at org.springframework.boot.sql.init.dependency.DatabaseInitializationDependencyConfigurer$DependsOnDatabaseInitializationPostProcessor.detectDependsOnInitializationBeanNames(DatabaseInitializationDependencyConfigurer.java:152) ~[spring-boot-3.4.1.jar:3.4.1]
	at org.springframework.boot.sql.init.dependency.DatabaseInitializationDependencyConfigurer$DependsOnDatabaseInitializationPostProcessor.postProcessBeanFactory(DatabaseInitializationDependencyConfigurer.java:115) ~[spring-boot-3.4.1.jar:3.4.1]
	at org.springframework.context.support.PostProcessorRegistrationDelegate.invokeBeanFactoryPostProcessors(PostProcessorRegistrationDelegate.java:363) ~[spring-context-6.2.1.jar:6.2.1]
	at org.springframework.context.support.PostProcessorRegistrationDelegate.invokeBeanFactoryPostProcessors(PostProcessorRegistrationDelegate.java:197) ~[spring-context-6.2.1.jar:6.2.1]
	at org.springframework.context.support.AbstractApplicationContext.invokeBeanFactoryPostProcessors(AbstractApplicationContext.java:791) ~[spring-context-6.2.1.jar:6.2.1]
	at org.springframework.context.support.AbstractApplicationContext.refresh(AbstractApplicationContext.java:609) ~[spring-context-6.2.1.jar:6.2.1]
	at org.springframework.boot.web.servlet.context.ServletWebServerApplicationContext.refresh(ServletWebServerApplicationContext.java:146) ~[spring-boot-3.4.1.jar:3.4.1]
	at org.springframework.boot.SpringApplication.refresh(SpringApplication.java:752) ~[spring-boot-3.4.1.jar:3.4.1]
	at org.springframework.boot.SpringApplication.refreshContext(SpringApplication.java:439) ~[spring-boot-3.4.1.jar:3.4.1]
	at org.springframework.boot.SpringApplication.run(SpringApplication.java:318) ~[spring-boot-3.4.1.jar:3.4.1]
	at michael.spica.mybatis.plus.MichaelSpicaMybatisPlusApplication.main(MichaelSpicaMybatisPlusApplication.java:42) ~[classes/:na]

问题排查

1. 检查 @MapperScan 的路径

@MapperScan 注解中提供的包路径正确，并且能够扫描到 UserMapper 类；路径不正确可能导致 Spring 不能正确地创建和管理 Mapper Bean。

@SpringBootApplication
@MapperScan("michael.spica.mybatis.plus.mapper")
public class MichaelSpicaMybatisPlusApplication {
   
   
    public static void main(String[] args) {
   
   
        SpringApplication.run(MichaelSpicaMybatisPlusApplication.class, args);
    }
}

2. 项目中没有配置 FactoryBean

从错误信息来看，factoryBeanObjectType 设置为了 String 类型，而应该是 Class 类型。

MyBatis 会自动生成 Mapper 接口的代理实现对象，而你不应该手动配置 FactoryBean。

@Bean
public MapperFactoryBean<UserMapper> userMapper() {
   
   
    MapperFactoryBean