基于Spring整合mybatis的mapper生成过程

Spring整合mybatis的mapper生成过程

mapperScannerConfigurer实现了BeandifinitionRegistryPostProcessor

后置处理beanFactory时会调用其postProcessBeanDefinitionRegistry

public void postProcessBeanDefinitionRegistry(BeanDefinitionRegistry registry) {
    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.setMapperFactoryBeanClass(this.mapperFactoryBeanClass);
    scanner.registerFilters();
//扫描包集合，注册mapper的beandifinition
    scanner.scan(StringUtils.tokenizeToStringArray(this.basePackage, ConfigurableApplicationContext.CONFIG_LOCATION_DELIMITERS));
  }

ClassPathMapperScanner#doScan

public Set<BeanDefinitionHolder> doScan(String... basePackages) {
    Set<BeanDefinitionHolder> beanDefinitions = super.doScan(basePackages);
 
    if (beanDefinitions.isEmpty()) {
      LOGGER.warn(() -> "No MyBatis mapper was found in '" + Arrays.toString(basePackages) + "' package. Please check your configuration.");
    } else {
//会对bean信息进行一些更改和添加，如设置propertyValues，向其中添加sqlsessionFactory等属性信息等
      processBeanDefinitions(beanDefinitions);
    }
 
    return beanDefinitions;
  }

ClassPathBeanDefinitionScanner#doScan

protected Set<BeanDefinitionHolder> doScan(String... basePackages) {
		Assert.notEmpty(basePackages, "At least one base package must be specified");
		Set<BeanDefinitionHolder> beanDefinitions = new LinkedHashSet<>();
		for (String basePackage : basePackages) {
//遍历集合扫描包，获取包下的可用的mapper信息
			Set<BeanDefinition> candidates = findCandidateComponents(basePackage);
			for (BeanDefinition candidate : candidates) {
				ScopeMetadata scopeMetadata = this.scopeMetadataResolver.resolveScopeMetadata(candidate);
				candidate.setScope(scopeMetadata.getScopeName());
				String beanName = this.beanNameGenerator.generateBeanName(candidate, this.registry);
				if (candidate instanceof AbstractBeanDefinition) {
					postProcessBeanDefinition((AbstractBeanDefinition) candidate, beanName);
				}
				if (candidate instanceof AnnotatedBeanDefinition) {
					AnnotationConfigUtils.processCommonDefinitionAnnotations((AnnotatedBeanDefinition) candidate);
				}
				if (checkCandidate(beanName, candidate)) {
					BeanDefinitionHolder definitionHolder = new BeanDefinitionHolder(candidate, beanName);
					definitionHolder =
							AnnotationConfigUtils.applyScopedProxyMode(scopeMetadata, definitionHolder, this.registry);
					beanDefinitions.add(definitionHolder);
					registerBeanDefinition(definitionHolder, this.registry);
				}
			}
		}
		return beanDefinitions;
	}

如上在进行包扫描时，会调用ClassPathBeanDefinitionScanner#doScan，进行beanDefinition的扫描和注册

执行完后调用ClassPathMapperScanner#processBeanDefinitions

private void processBeanDefinitions(Set<BeanDefinitionHolder> beanDefinitions) {
//有省略部分
       
    //这里有遍历所有mapper
//将所有mapper的beanClass改为了mapperFactoryBean，最后生成的bean也是该类型的，只有在用到的
//时候才会调用getObject生成mapper
      definition.setBeanClass(this.mapperFactoryBeanClass);
//接下来是添加一些MapperFactoryBean的属性信息到beandefinition里，在生成实例的时候，会根据
//此处传入的值来进行具体设置，如sqlsessionFactory
      definition.getPropertyValues().add("addToConfig", this.addToConfig);
 
      
      if (StringUtils.hasText(this.sqlSessionFactoryBeanName)) {
        definition.getPropertyValues().add("sqlSessionFactory", new RuntimeBeanReference(this.sqlSessionFactoryBeanName));
      
      } else if (this.sqlSessionFactory != null) {
        definition.getPropertyValues().add("sqlSessionFactory", this.sqlSessionFactory);
        
      }
 
      if (StringUtils.hasText(this.sqlSessionTemplateBeanName)) {
        
        definition.getPropertyValues().add("sqlSessionTemplate", new RuntimeBeanReference(this.sqlSessionTemplateBeanName));
        
      } else if (this.sqlSessionTemplate != null) {
        
        definition.getPropertyValues().add("sqlSessionTemplate", this.sqlSessionTemplate);
        
      }
  }