SpringBoot多数据源

目前最优的方式是，注入多个datasource 然后通过org.springframework.jdbc.datasource.lookup.AbstractRoutingDataSource在执行得时候设置根据key设置当前上下文不同的datasource，通过@Primary设置实现类为默认数据源。在事务中不支持数据源切换，因为事务默认不是分布式不跨库的。

下面这是为不同mapper设置不同datasource的方式，不优雅。

@Configuration
@MapperScan(basePackages = "com.activitytomongo.mapper", sqlSessionTemplateRef = "promoteSqlSessionTemplate")
public class PromoteDatasourceConfig {
    
    @Bean(name = "promoteDatasource")
    @ConfigurationProperties(prefix = "spring.datasource.promote")
    public DataSource setPromoteDataSource() {
        return DataSourceBuilder.create().build();
    }

    @Bean(name = "promoteTransactionManager")
    public PlatformTransactionManager promoteSqlSessionTemplate(@Qualifier("promoteDatasource") DataSource dataSource) {
        return new DataSourceTransactionManager(dataSource);
    }

    @Bean(name = "promoteSqlSessionFactory")
    public SqlSessionFactory promoteSqlSessionFactory(@Qualifier("promoteDatasource") DataSource dataSource) throws Exception {
        SqlSessionFactoryBean bean = new SqlSessionFactoryBean();
        bean.setDataSource(dataSource);
        return bean.getObject();
    }

    @Bean(name = "promoteSqlSessionTemplate")
    public SqlSessionTemplate setSqlSessionTemplate(
            @Qualifier("promoteSqlSessionFactory") SqlSessionFactory sqlSessionFactory) throws Exception {
        // return new SqlSessionTemplate(sqlSessionFactory);
        return new SqlSessionTemplate(sqlSessionFactory, ExecutorType.BATCH);
    }
}