当前位置：首页 > news >正文

Spring注解方式整合Mybatis

news 2026/5/12 12:28:20

Spring注解方式整合Mybatis

一、概述

二、实验

2.1注入数据源的各属性

先引入配置文件：

@PropertySource("classpath:jdbc.properties")

再是注入属性：

@Value("${jdbc.driver}")StringdriverClassName;@Value("${jdbc.url}")Stringurl;@Value("${jdbc.username}")Stringusername;@Value("${jdbc.password}")Stringpassword;

2.2创建数据源且注册成为Bean

@BeanpublicDataSourcedataSource(){DruidDataSourcedataSource=newDruidDataSource();dataSource.setDriverClassName(driverClassName);dataSource.setUsername(username);dataSource.setPassword(password);dataSource.setUrl(url);returndataSource;}

2.3创建SqlSessionFactoryBean且注册成为Bean

publicSqlSessionFactoryBeansqlSessionFactoryBean(DataSourcedataSource){// SqlSessionFactoryBean sqlSessionFactoryBean = sqlSessionFactoryBean(dataSource);SqlSessionFactoryBeansqlSessionFactoryBean=newSqlSessionFactoryBean();sqlSessionFactoryBean.setDataSource(dataSource);returnsqlSessionFactoryBean;}

2.4设置接口扫描

@ComponentScan("com.itheima")

总的配置类（里面含有xml配置的对照）：

packagecom.itheima.config;importcom.alibaba.druid.pool.DruidDataSource;importcom.itheima.beans.OtherBean3;importorg.mybatis.spring.SqlSessionFactoryBean;importorg.mybatis.spring.annotation.MapperScan;importorg.springframework.beans.factory.annotation.Value;importorg.springframework.context.annotation.*;importjavax.sql.DataSource;//这个注解代表：这是一个核心配置类；这个类交给了Spring容器管理（就是相当于替换Spring配置文件）@Configuration//<context:component-scan base-package="com.itheima"/>：配置注解扫描，只有一个时直接写，有多个写成数组@ComponentScan("com.itheima")//<context:property-placeholder location="classpath:jdbc.properties"/>：引入配置文件@PropertySource("classpath:jdbc.properties")// <import resource=""：导入其他配置类@Import(OtherBean3.class)//下面是接口扫描// <bean class="org.mybatis.spring.mapper.MapperScannerConfigurer">//<!-- 指定要扫描的包-->// <property name="basePackage" value="com.itheima.mapper"></property>// </bean>@MapperScan("com.itheima.mapper")publicclassSpringConfig2{@Value("${jdbc.driver}")StringdriverClassName;@Value("${jdbc.url}")Stringurl;@Value("${jdbc.username}")Stringusername;@Value("${jdbc.password}")Stringpassword;// <bean id="dataSource" class="com.alibaba.druid.pool.DruidDataSource">// <property name="driverClassName" value="${jdbc.driver}"/>// <property name="url" value="${jdbc.url}"/>// <property name="username" value="${jdbc.username}"/>// <property name="password" value="${jdbc.password}"/>// </bean>@BeanpublicDataSourcedataSource(){DruidDataSourcedataSource=newDruidDataSource();dataSource.setDriverClassName(driverClassName);dataSource.setUsername(username);dataSource.setPassword(password);dataSource.setUrl(url);returndataSource;}// <bean class="org.mybatis.spring.SqlSessionFactoryBean">//<!-- 最终是要得到由Sqlsession得到Conection，需要数据源属性-->// <property name="dataSource" ref="dataSource"></property>// </bean>@Bean// 在这里是通过类型进行注入的publicSqlSessionFactoryBeansqlSessionFactoryBean(DataSourcedataSource){// SqlSessionFactoryBean sqlSessionFactoryBean = sqlSessionFactoryBean(dataSource);SqlSessionFactoryBeansqlSessionFactoryBean=newSqlSessionFactoryBean();sqlSessionFactoryBean.setDataSource(dataSource);returnsqlSessionFactoryBean;}}

结果：

三、原理剖析

先是进入@MapperScan看看里面：

@MapperScan("com.itheima.mapper")

//// Source code recreated from a .class file by IntelliJ IDEA// (powered by FernFlower decompiler)//packageorg.mybatis.spring.annotation;importjava.lang.annotation.Annotation;importjava.lang.annotation.Documented;importjava.lang.annotation.ElementType;importjava.lang.annotation.Repeatable;importjava.lang.annotation.Retention;importjava.lang.annotation.RetentionPolicy;importjava.lang.annotation.Target;importorg.mybatis.spring.mapper.MapperFactoryBean;importorg.springframework.beans.factory.support.BeanNameGenerator;importorg.springframework.context.annotation.Import;@Retention(RetentionPolicy.RUNTIME)@Target({ElementType.TYPE})@Documented@Import({MapperScannerRegistrar.class})@Repeatable(MapperScans.class)public@interfaceMapperScan{String[]value()default{};String[]basePackages()default{};Class<?>[]basePackageClasses()default{};Class<?extendsBeanNameGenerator>nameGenerator()defaultBeanNameGenerator.class;Class<?extendsAnnotation>annotationClass()defaultAnnotation.class;Class<?>markerInterface()defaultClass.class;StringsqlSessionTemplateRef()default"";StringsqlSessionFactoryRef()default"";Class<?extendsMapperFactoryBean>factoryBean()defaultMapperFactoryBean.class;StringlazyInitialization()default"";}

我们发现它导入了一个MapperScannerRegistrar，继续跟进：

voidregisterBeanDefinitions(AnnotationMetadataannoMeta,AnnotationAttributesannoAttrs,BeanDefinitionRegistryregistry,StringbeanName){BeanDefinitionBuilderbuilder=BeanDefinitionBuilder.genericBeanDefinition(MapperScannerConfigurer.class);builder.addPropertyValue("processPropertyPlaceHolders",true);Class<?extendsAnnotation>annotationClass=annoAttrs.getClass("annotationClass");if(!Annotation.class.equals(annotationClass)){builder.addPropertyValue("annotationClass",annotationClass);}

然后注册了一个MapperScannerConfigurer.class，是不是好熟悉啊？其实到这就是与xml配置一样了，都是通过MapperScannerConfigurer.class来注册，只不过注解方式还导入了一个MapperScannerRegistrar，再由MapperScannerRegistrar注册MapperScannerConfigurer.class，而xml方式是直接配置MapperScannerConfigurer.class。当然我们也还可以发现BeanDefinitionBuilder.genericBeanDefinition(MapperScannerConfigurer.class);，BeanDefinitionBuilder也是可以注册BeanDefinition的，以前我们都是通过new RootBeanDefinition()，然后由BeanDefinitionRegistry注册，现在又发现一种方式。

publicvoidpostProcessBeanDefinitionRegistry(BeanDefinitionRegistryregistry){if(this.processPropertyPlaceHolders){this.processPropertyPlaceHolders();}ClassPathMapperScannerscanner=newClassPathMapperScanner(registry);scanner.setAddToConfig(this.addToConfig);scanner.setAnnotationClass(this.annotationClass);scanner.setMarkerInterface(this.markerInterface);scanner.setSqlSessionFactory(this.sqlSessionFactory);scanner.setSqlSessionTemplate(this.sqlSessionTemplate);scanner.setSqlSessionFactoryBeanName(this.sqlSessionFactoryBeanName);scanner.setSqlSessionTemplateBeanName(this.sqlSessionTemplateBeanName);scanner.setResourceLoader(this.applicationContext);scanner.setBeanNameGenerator(this.nameGenerator);scanner.setMapperFactoryBeanClass(this.mapperFactoryBeanClass);if(StringUtils.hasText(this.lazyInitialization)){scanner.setLazyInitialization(Boolean.valueOf(this.lazyInitialization));}scanner.registerFilters();scanner.scan(StringUtils.tokenizeToStringArray(this.basePackage,",; \t\n"));}

看吧，依然是调用postProcessBeanDefinitionRegistry的scanner.scan(StringUtils.tokenizeToStringArray(this.basePackage, “,; \t\n”));，然后进入scan方法：

protectedSet<BeanDefinitionHolder>doScan(String...basePackages){Assert.notEmpty(basePackages,"At least one base package must be specified");Set<BeanDefinitionHolder>beanDefinitions=newLinkedHashSet();for(StringbasePackage:basePackages){for(BeanDefinitioncandidate:this.findCandidateComponents(basePackage)){ScopeMetadatascopeMetadata=this.scopeMetadataResolver.resolveScopeMetadata(candidate);candidate.setScope(scopeMetadata.getScopeName());StringbeanName=this.beanNameGenerator.generateBeanName(candidate,this.registry);if(candidateinstanceofAbstractBeanDefinition){this.postProcessBeanDefinition((AbstractBeanDefinition)candidate,beanName);}if(candidateinstanceofAnnotatedBeanDefinition){AnnotationConfigUtils.processCommonDefinitionAnnotations((AnnotatedBeanDefinition)candidate);}if(this.checkCandidate(beanName,candidate)){BeanDefinitionHolderdefinitionHolder=newBeanDefinitionHolder(candidate,beanName);definitionHolder=AnnotationConfigUtils.applyScopedProxyMode(scopeMetadata,definitionHolder,this.registry);beanDefinitions.add(definitionHolder);this.registerBeanDefinition(definitionHolder,this.registry);}}}returnbeanDefinitions;}