* 
第一种可以直接使用starter的mybatis plus,快速开发
<dependency> <groupId>com.baomidou</groupId> <artifactId>mybatis-plus-boot-
starter</artifactId> <version>3.3.1</version> </dependency> <!-- mybatis-
plus代码生成器--> <dependency> <groupId>com.baomidou</groupId> <artifactId>mybatis-
plus-generator</artifactId> <version>3.3.1.tmp</version> </dependency> mybatis-
plus: # xml文件路径 mapper-locations: classpath:mapper/*.xml # 实体类路径 
type-aliases-package: com.数据库表对应的实体类的路径 configuration: # 驼峰转换 
map-underscore-to-camel-case: true # 是否开启缓存 cache-enabled: false # 打印sql 
log-impl: org.apache.ibatis.logging.stdout.StdOutImpl # 全局配置 global-config: # 
数据库字段驼峰下划线转换 db-column-underline: true # id自增类型(数据库id自增) id-type: 0 
 * 
自己开发配置类,先导入mybatis plus的jar包,用pom文件导入
<dependency> <groupId>com.baomidou</groupId> <artifactId>mybatis-plus-generator
</artifactId> <version>3.3.1</version> </dependency> mybatis-plus: # xml文件路径 
mapper-locations: classpath:mapper/*.xml # 实体类路径 type-aliases-package: 
com.数据库表对应的实体类的路径 configuration: # 驼峰转换 map-underscore-to-camel-case: true # 
是否开启缓存 cache-enabled: false # 打印sql log-impl: 
org.apache.ibatis.logging.stdout.StdOutImpl # 全局配置 global-config: # 
数据库字段驼峰下划线转换 db-column-underline: true # id自增类型(数据库id自增) id-type: 0 
配置类,主要代码,其实starter就是主要创建了这个bean,不需要我们创建了
 @Bean public SqlSessionFactory sqlSessionFactory(DataSource dataSource) 
throws Exception{ String typeAliasesPackage = env.getProperty(
"mybatis.typeAliasesPackage"); String mapperLocations = env.getProperty(
"mybatis.mapperLocations"); String configLocation = env.getProperty(
"mybatis.configLocation"); typeAliasesPackage = setTypeAliasesPackage(
typeAliasesPackage); VFS.addImplClass(SpringBootVFS.class); //配置mybatis-plus的 
sqlSessionFactory final MybatisSqlSessionFactoryBean sessionFactory = new 
MybatisSqlSessionFactoryBean(); sessionFactory.setDataSource(dataSource); 
sessionFactory.setTypeAliasesPackage(typeAliasesPackage); sessionFactory.
setMapperLocations(resolveMapperLocations(StringUtils.split(mapperLocations, ","
))); sessionFactory.setConfigLocation(new DefaultResourceLoader().getResource(
configLocation)); return sessionFactory.getObject(); }