一，单个数据源，单个事务管理器与@Transactional默认事务管理器名称不一致问题

在平时代码中使用声明性事务时，直接在方法上面加注解即可，如下

@Transactional(rollbackFor = Exception.class)

并没有指定事务管理器，为什么？

因为只有一个数据源，只有一个事物管理器。多数据源，多个事物管理器时才需要指定事务管理器

如下创建事物管理器

@Bean(name = "defaultTransactionManager")
@Primary
public DataSourceTransactionManager defaultDataSourceTransactionManager(@Qualifier("defaultDataSource") DataSource dataSource) {return new DataSourceTransactionManager(dataSource);
}

但是创建的事物管理器名称是 defaultTransactionManager 

@Transactional 注解中默认的事物器管理器是 transactionManager

为什么依然有效 

参考文章

千云物流- 多数据源事务管理_多数据源datasourcetransactionmanager-CSDN博客

SpringBoot手动开启事务：DataSourceTransactionManager-CSDN博客

【老王读Spring Transaction-7】一个数据源的事物管理配置 与 多数据源的事物管理配置_springboot 配置 @transactional 的数据源-CSDN博客

二，相关知识点

1，@Transactional注解不生效问题

常见情况：

1，方法内部调用：

一个类中，A方法调用加了事物注解的B方法；或A事物方法调用B事物方法，B事物依然不会生效

2，方法不是public

3，多数据源情况，事物管理器没有指定正确

4，@Transactional 注解属性 rollbackFor 设置错误

5，异常被catch了

6，自调用：事物方法A，内部调用的类中无事物方法B，如果B抛出异常，A方法其他内容不回滚

Spring @Transactional注解失效的情况及解决方法_@transactional注解不生效-CSDN博客

针对第六点方案有疑问

2，编程性事物 

为了解决大事物问题

3，SqlSessionFactory 创建

包含：如果是mybatisplus如何配置，如何指定xml路基

@Configuration
@MapperScan(basePackages = {"com.*","com.*"}, sqlSessionFactoryRef = "mallSqlSessionFactory")
public class DataBaseConfig {private static final Logger logger = LoggerFactory.getLogger(Constant.LOGGER);@Value("${spring.datasource.mall.druid.filters:stat}")private String filter;@Value("${spring.datasource.mall.druid.maxActive:20}")private int maxActive;@Value("${spring.datasource.mall.druid.minIdle:5}")private int minIdle;@Value("${spring.datasource.mall.druid.initialSize:5}")private int initialSize;@Value("${spring.datasource.mall.druid.maxWait:90000}")private int maxWait;@Value("${spring.datasource.mall.druid.timeBetweenEvictionRunsMillis:60000}")private int timeBetweenEvictionRunsMillis;@Value("${spring.datasource.mall.druid.minEvictableIdleTimeMillis:3000000}")private int minEvictableIdleTimeMillis;@Value("${spring.datasource.mall.druid.poolPreparedStatements:false}")private boolean poolPreparedStatements ;@Bean(name = "mallDataSource")@ConfigurationProperties(prefix = "spring.datasource.mall")public DataSource mallDataSource() {//指定使用DruidDataSourceDruidDataSource dataSource = (DruidDataSource) DataSourceBuilder.create().type(com.alibaba.druid.pool.DruidDataSource.class).build();try {dataSource.setInitialSize(initialSize);dataSource.setMinIdle(minIdle);dataSource.setMaxActive(maxActive);dataSource.setMaxWait(maxWait);dataSource.setTimeBetweenEvictionRunsMillis(timeBetweenEvictionRunsMillis);dataSource.setMinEvictableIdleTimeMillis(minEvictableIdleTimeMillis);dataSource.setPoolPreparedStatements(poolPreparedStatements);dataSource.setFilters(filter);logger.info("初始化mallDataSource Druid监控配置成功");}catch (Exception e){logger.warn("初始化Druid监控配置失败");}return dataSource;}@Bean(name = "mallSqlSessionFactory")public SqlSessionFactory mallSqlSessionFactory(@Qualifier("mallDataSource") DataSource dataSource)throws Exception {MybatisSqlSessionFactoryBean bean = new MybatisSqlSessionFactoryBean();//SqlSessionFactoryBean bean = new SqlSessionFactoryBean();bean.setDataSource(dataSource);Interceptor[] plugins =  new Interceptor[]{new PageHelper()};bean.setPlugins(plugins);List<String> mapperLocations = new ArrayList<>();mapperLocations.add("classpath:mybatis/mappers/customer/*.xml");mapperLocations.add("classpath:mybatis/mappers/community/*.xml");Resource[] resources = resolveMapperLocations(mapperLocations);bean.setMapperLocations(resources);return bean.getObject();}@Bean(name = "mallTransactionManager")public PlatformTransactionManager mallTransactionManager(@Qualifier("mallDataSource") DataSource dataSource) {return new DataSourceTransactionManager(dataSource);}@Bean(name = "mallSqlSessionTemplate")public SqlSessionTemplate mallSqlSessionTemplate(@Qualifier("mallSqlSessionFactory") SqlSessionFactory sqlSessionFactory) throws Exception {return new SqlSessionTemplate(sqlSessionFactory);}/*** 指定多路径*/private Resource[] resolveMapperLocations(List<String> mapperLocations) {ResourcePatternResolver resourceResolver = new PathMatchingResourcePatternResolver();List<Resource> resources = new ArrayList();if (mapperLocations != null) {for (String mapperLocation : mapperLocations) {try {Resource[] mappers = resourceResolver.getResources(mapperLocation);resources.addAll(Arrays.asList(mappers));} catch (IOException e) {throw new RuntimeException(e);}}}return resources.toArray(new Resource[0]);}
}

   @Bean(name = "defaultSqlSessionFactory")@Primarypublic SqlSessionFactory defaultSqlSessionFactory(@Qualifier("defaultDataSource") DataSource dataSource)throws Exception {MybatisSqlSessionFactoryBean bean = new MybatisSqlSessionFactoryBean();bean.setDataSource(dataSource);Interceptor[] plugins = {paginationInterceptor};bean.setPlugins(plugins);bean.setMapperLocations(new PathMatchingResourcePatternResolver().getResources("classpath*:mapper/*.xml"));GlobalConfig globalConfig = new GlobalConfig();globalConfig.setMetaObjectHandler(new MyMetaObjectHandler());bean.setGlobalConfig(globalConfig);return bean.getObject();}