自动扫描 将Mapper接口生成代理注入到Spring

1	<!-- DAO接口所在包名，Spring会自动查找其下的类 -->
2	<bean class="org.mybatis.spring.mapper.MapperScannerConfigurer">
3		<property name="basePackage" value="com.em" />
4		<property name="sqlSessionFactoryBeanName" value="sqlSessionFactory"></property>
5	</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(); }

  1ClassPathMapperScanner scanner = new ClassPathMapperScanner(registry);
  2scanner.setAddToConfig(this.addToConfig);
  3scanner.setAnnotationClass(this.annotationClass);
  4scanner.setMarkerInterface(this.markerInterface);
  5scanner.setSqlSessionFactory(this.sqlSessionFactory);
  6scanner.setSqlSessionTemplate(this.sqlSessionTemplate);
  7scanner.setSqlSessionFactoryBeanName(this.sqlSessionFactoryBeanName);
  8scanner.setSqlSessionTemplateBeanName(this.sqlSessionTemplateBeanName);
  9scanner.setResourceLoader(this.applicationContext);
  10scanner.setBeanNameGenerator(this.nameGenerator);
  11scanner.registerFilters();
  12scanner.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

    • 1  public void afterPropertiesSet() throws Exception {
      2      Assert.notNull(this.dataSource, "Property 'dataSource' is required");
      3      Assert.notNull(this.sqlSessionFactoryBuilder, "Property 'sqlSessionFactoryBuilder' is required");
      4      this.sqlSessionFactory = this.buildSqlSessionFactory();
      5  }