相关项目地址:https://github.com/helloworlde/SpringBoot-DynamicDataSource
1. org.apache.ibatis.binding.BindingException: Invalid bound statement (not found)
在使用了动态数据源后遇到了该问题,从错误信息来看是因为没有找到
*.xml
文件而导致的,但是在配置文件中
确实添加了相关的配置,这种错误的原因是因为设置数据源后没有设置SqlSessionFactoryBean
的typeAliasesPackage
和mapperLocations
属性或属性无效导致的;
- 解决方法:
如果在应用的入口类中添加了
@SpringBootApplication(exclude = DataSourceAutoConfiguration.class)
,
在DataSourceConfigure
类的中设置相关属性:
@Bean @ConfigurationProperties(prefix = "mybatis")
public SqlSessionFactoryBean sqlSessionFactoryBean() {
SqlSessionFactoryBean sqlSessionFactoryBean = new SqlSessionFactoryBean();
sqlSessionFactoryBean.setDataSource(dynamicDataSource());
return sqlSessionFactoryBean;
}
或者直接配置(不推荐该方式):
@Bean
public SqlSessionFactoryBean sqlSessionFactoryBean() {
SqlSessionFactoryBean sqlSessionFactoryBean = new SqlSessionFactoryBean();
sqlSessionFactoryBean.setTypeAliasesPackage("typeAliasesPackage");
sqlSessionFactoryBean.setMapperLocations(new PathMatchingResourcePatternResolver().getResources("mapperLocations"));
sqlSessionFactoryBean.setDataSource(dynamicDataSource());
return sqlSessionFactoryBean;
}
2. Consider marking one of the beans as @Primary, updating the consumer to accept multiple beans, or using @Qualifier to identify the bean that should be consumed
该异常在错误信息中已经说的很清楚了,是因为有多个
DataSource
的实例,所以无法确定该引用那个实例
- 解决方法:
为数据源的某个
Bean
添加@Primary
注解,该Bean
应当是通过DataSourceBuilder.create().build()
得到的Bean
,而不是通过new AbstractRoutingDataSource
的子类实现的Bean
,在本项目中可以是master()
或slave()
得到的DataSource
,不能是dynamicDataSource()
得到的DataSource
3. 通过注解方式动态切换数据源无效
- 请确认注解没有放到 DAO 层方法上, 因为会在 Service 层开启事务,所以当注解在 DAO 层时不会生效
- 请确认以下
Bean
正确配置:
@Bean("dynamicDataSource")
public DataSource dynamicDataSource() {
DynamicRoutingDataSource dynamicRoutingDataSource = new DynamicRoutingDataSource();
Map<Object, Object> dataSourceMap = new HashMap<>(2);
dataSourceMap.put("master", master());
dataSourceMap.put("slave", slave());
// Set master datasource as default
dynamicRoutingDataSource.setDefaultTargetDataSource(master());
// Set master and slave datasource as target datasource
dynamicRoutingDataSource.setTargetDataSources(dataSourceMap);
// To put datasource keys into DataSourceContextHolder to judge if the datasource is exist
DynamicDataSourceContextHolder.dataSourceKeys.addAll(dataSourceMap.keySet());
}
return dynamicRoutingDataSource;
}
@Bean
@ConfigurationProperties(prefix = "mybatis")
public SqlSessionFactoryBean sqlSessionFactoryBean() {
SqlSessionFactoryBean sqlSessionFactoryBean = new SqlSessionFactoryBean();
// Here is very important, if don‘t config this, will can‘t switch datasource
// put all datasource into SqlSessionFactoryBean, then will autoconfig SqlSessionFactory
sqlSessionFactoryBean.setDataSource(dynamicDataSource());
return sqlSessionFactoryBean;
}
4. @Transactional
注解无效,发生异常不回滚
- 请确认该
Bean
得到正确配置,并且@Transactional
的rollbackFor
配置正确
@Bean
public PlatformTransactionManager transactionManager() {
return new DataSourceTransactionManager(dynamicDataSource());
}
5. 通过 AOP 判断 DAO 层方法名时切换数据源无效
当切面指向了 DAO 层后无论如何设置切面的顺序,都无法在执行查询之前切换数据源,但是切面改为 Service 层后可以正常工作
解决方法: 请确认
@Transactional
注解是加在方法上而不是 Service 类上,添加了@Transactional
的方法因为在 Service 层开启了事务,
会在事务结束之后才会切换数据源检出
DataSourceTransactionManager
Bean 注入正确
@Bean
public PlatformTransactionManager transactionManager() {
return new DataSourceTransactionManager(dynamicDataSource());
}
6. The dependencies of some of the beans in the application context form a cycle
- 错误信息:
The dependencies of some of the beans in the application context form a cycle:
produceController (field private cn.com.hellowood.dynamicdatasource.service.ProductService cn.com.hellowood.dynamicdatasource.controller.ProduceController.productService)
↓
productService (field private cn.com.hellowood.dynamicdatasource.mapper.ProductDao cn.com.hellowood.dynamicdatasource.service.ProductService.productDao)
↓
productDao defined in file [/Users/hehuimin/Downloads/Dev/SpringBoot/DynamicDataSource/out/production/classes/cn/com/hellowood/dynamicdatasource/mapper/ProductDao.class]
↓
sqlSessionFactoryBean defined in class path resource [cn/com/hellowood/dynamicdatasource/configuration/DataSourceConfigurer.class]
┌─────┐
| dynamicDataSource defined in class path resource [cn/com/hellowood/dynamicdatasource/configuration/DataSourceConfigurer.class]
↑
↓
| master defined in class path resource [cn/com/hellowood/dynamicdatasource/configuration/DataSourceConfigurer.class]
↑
↓
| dataSourceInitializer
└─────┘
这是因为在注入
DataSource
的实例的时候产生了循环调用,第一个注入的 Bean 依赖于其他的 Bean, 而被依赖的 Bean 产生依赖传递,依赖第一个
注入的 Bean, 陷入了循环,无法启动项目
- 解决方法:将
@Primary
注解指向没有依赖的 Bean,如:
/**
* master DataSource
* @Primary 注解用于标识默认使用的 DataSource Bean,因为有三个 DataSource Bean,该注解可用于 master
* 或 slave DataSource Bean, 但不能用于 dynamicDataSource Bean, 否则会产生循环调用
* * @ConfigurationProperties 注解用于从 application.properties 文件中读取配置,为 Bean 设置属性
* @return data source
*/
@Bean("master")
@Primary
@ConfigurationProperties(prefix = "application.server.db.master")
public DataSource master() {
return DataSourceBuilder.create().build();
} @Bean("slave")
@ConfigurationProperties(prefix = "application.server.db.slave")
public DataSource slave() {
return DataSourceBuilder.create().build();
} @Bean("dynamicDataSource")
public DataSource dynamicDataSource() {
DynamicRoutingDataSource dynamicRoutingDataSource = new DynamicRoutingDataSource();
Map<Object, Object> dataSourceMap = new HashMap<>(2);
dataSourceMap.put("master", master());
dataSourceMap.put("slave", slave());
// Set master datasource as default
dynamicRoutingDataSource.setDefaultTargetDataSource(master());
// Set master and slave datasource as target datasource
dynamicRoutingDataSource.setTargetDataSources(dataSourceMap);
// To put datasource keys into DataSourceContextHolder to judge if the datasource is exist
DynamicDataSourceContextHolder.dataSourceKeys.addAll(dataSourceMap.keySet());
return dynamicRoutingDataSource;
}