@ mappers can @ mappers can ((com.kq.my batis.mapper )，' com.kq.my batis1. mapper ' } publicvoidregisterbeandefinition beandefinitionregistryregistry (annotationattributesmapperscanattrs=annotation attributes.from map (导入分类元数据映射扫描器！=null (注册beandefinitions (mapperscanattrs，registry，generatebasebeanname ) importingclassmetadata，0 ) )； }
缺省情况下，这是扫描com.kq.mybatis.mapper文件和com.kq.mybatis1.mapper包中的所有. clsss文件
@MapperScan指定标记器接口在此指定@MapperScan指定标记器接口将扫描实现该接口的标记器
@ mappers can (value={ ' com.kq.scan.my batis.mapper '，' com.kq.scan.mybatis1.mapper'}， mapper interface=mybatisbasemapper.class ) publicinterfaceaccountmapperextendsmybatisbasemapper { }此marker界面最终设置
@MapperScan指定annotation class @ mappers can (value={ ' com.kq.scan.my batis.mapper '，' com.kq.scan.my batis1. ) annotationClass=Mapper.class ) @ mapperpublicinterfaceusermapper { }此annotass
注意：如果@MapperScan同时指定了markerInterface和annotationClass元素，则只要满足一个条件，就可以满足两个条件而不是两个条件
mapperscannerregistrarbeandefinitionbuilderbuilder=beandefinitionbuilder.genericbeandefinition (builder.add property valuinition Class？ extendsannotationannotationclass=anno attrs.getclass (annotation class )； if (！ annotation.class.equals (annotationclass ) ) builder.addpropertyvalue )、annotation class )； //看这里marker接口类？ marker接口=anno attrs.getclass (marker接口)； if (！ class.class.equals (标记接口) ) builder.add property value ('标记器接口'，标记器接口)； }
@ mapper scans @ mapper scans ({ @ mappers can ) ' com.kq.myBatis.mapper ' )、@ mappers can (com.kq.my batis1. mapper staticclassrepeatingregistrarextendsmapperscannerregistrar { @ overridepublicvoidregisterbeandefinitions (注释元数据)
AnnotationAttributes mapperScansAttrs = AnnotationAttributes .fromMap(importingClassMetadata.getAnnotationAttributes(MapperScans.class.getName())); if (mapperScansAttrs != null) { AnnotationAttributes[] annotations = mapperScansAttrs.getAnnotationArray("value"); for (int i = 0; i < annotations.length; i++) { registerBeanDefinitions(annotations[i], registry, generateBaseBeanName(importingClassMetadata, i)); } } } }使用@MapperScans，spring的bean定义，注册的MapperScannerRegistrar 有多个的，看上图
注意
每个@MapperScan最终都会初始化1个MapperScannerConfigurer，主要关键的属性basePackage、annotationClass、markerInterface
主要相关类 org.mybatis.spring.annotation.MapperScannerRegistrarorg.mybatis.spring.mapper.MapperScannerConfigurer 类图
总结
@MapperScan主要就是扫描得到mybatis的Mapper，并最终在Spring容器种初始化
未配置@MapperScan org.mybatis.spring.boot.autoconfigure.MybatisAutoConfiguration /** * If mapper registering configuration or mapper scanning configuration not present, this configuration allow to scan * mappers based on the same component-scanning path as Spring Boot itself. */ @org.springframework.context.annotation.Configuration @Import(AutoConfiguredMapperScannerRegistrar.class) @ConditionalOnMissingBean({ MapperFactoryBean.class, MapperScannerConfigurer.class }) public static class MapperScannerRegistrarNotFoundConfiguration implements InitializingBean { @Override public void afterPropertiesSet() { logger.debug( "Not found configuration for registering mapper bean using @MapperScan, MapperFactoryBean and MapperScannerConfigurer."); } }
重点看下面这句话
If mapper registering configuration or mapper scanning configuration not present, this configuration allow to scan
mappers based on the same component-scanning path as Spring Boot itself.
(如果不存在mapper注册配置或mapper扫描配置，则此配置允许扫描mapper基于与Spring Boot本身相同的组件扫描路径。)
AutoConfiguredMapperScannerRegistrar
org.mybatis.spring.boot.autoconfigure.MybatisAutoConfiguration
public static class AutoConfiguredMapperScannerRegistrar implements BeanFactoryAware, ImportBeanDefinitionRegistrar { private BeanFactory beanFactory; @Override public void registerBeanDefinitions(AnnotationMetadata importingClassMetadata, BeanDefinitionRegistry registry) { if (!AutoConfigurationPackages.has(this.beanFactory)) { logger.debug("Could not determine auto-configuration package, automatic mapper scanning disabled."); return; } logger.debug("Searching for mappers annotated with @Mapper"); List<String> packages = AutoConfigurationPackages.get(this.beanFactory); if (logger.isDebugEnabled()) { packages.forEach(pkg -> logger.debug("Using auto-configuration base package '{}'", pkg)); } BeanDefinitionBuilder builder = BeanDefinitionBuilder.genericBeanDefinition(MapperScannerConfigurer.class); builder.addPropertyValue("processPropertyPlaceHolders", true); builder.addPropertyValue("annotationClass", Mapper.class); //指定扫描的注解 builder.addPropertyValue("basePackage", StringUtils.collectionToCommaDelimitedString(packages)); //和springboot一致 BeanWrapper beanWrapper = new BeanWrapperImpl(MapperScannerConfigurer.class); Stream.of(beanWrapper.getPropertyDescriptors()) // Need to mybatis-spring 2.0.2+ .filter(x -> x.getName().equals("lazyInitialization")).findAny() .ifPresent(x -> builder.addPropertyValue("lazyInitialization", "${mybatis.lazy-initialization:false}")); registry.registerBeanDefinition(MapperScannerConfigurer.class.getName(), builder.getBeanDefinition()); } }