自动扫描 将Mapper接口生成代理注入到Spring

    <!-- DAO接口所在包名，Spring会自动查找其下的类 -->
    <bean class="org.mybatis.spring.mapper.MapperScannerConfigurer">
        <property name="basePackage" value="com.em" />
        <property name="sqlSessionFactoryBeanName" value="sqlSessionFactory"></property>
    </bean>

• MapperFactoryBean 创建的代理类实现了 UserMapper 接口,并且注入到应用程序中

• 把Mapper接口转换成MapperFactoryBean

  • 其实在SqlSessionFactoryBean 里面就已经实现了注册了 MapperProxyFactory 到Mybatis
  • 这里做的是把它们托管到spring

  { if (this.processPropertyPlaceHolders) { processPropertyPlaceHolders(); }

  ClassPathMapperScanner scanner = new ClassPathMapperScanner(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.registerFilters();
  scanner.scan(StringUtils.tokenizeToStringArray(this.basePackage, ConfigurableApplicationContext.CONFIG_LOCATION_DELIMITERS));
  

  }

• 注意，不管先后顺序

  • SqlSessionFactoryBean 继承了InitializingBean 接口

    • 会在所有spring 注册完成后，执行afterPropertiesSet方法

    •   public void afterPropertiesSet() throws Exception {
            Assert.notNull(this.dataSource, "Property 'dataSource' is required");
            Assert.notNull(this.sqlSessionFactoryBuilder, "Property 'sqlSessionFactoryBuilder' is required");
            this.sqlSessionFactory = this.buildSqlSessionFactory();
        }