相關項目地址:https://github.com/helloworlde/SpringBoot-DynamicDataSource
1. org.apache.ibatis.binding.BindingException: Invalid bound statement (not found)
在使用了動態數據源后遇到了該問題，從錯誤信息來看是因為沒有找到
*.xml文件而導致的，但是在配置文件中
確實添加了相關的配置，這種錯誤的原因是因為設置數據源后沒有設置SqlSessionFactoryBean的typeAliasesPackage
和mapperLocations屬性或屬性無效導致的；
- 解決方法：
如果在應用的入口類中添加了
@SpringBootApplication(exclude = DataSourceAutoConfiguration.class),
在DataSourceConfigure類的中設置相關屬性：
@Bean
@ConfigurationProperties(prefix = "mybatis")
public SqlSessionFactoryBean sqlSessionFactoryBean() {
SqlSessionFactoryBean sqlSessionFactoryBean = new SqlSessionFactoryBean();
sqlSessionFactoryBean.setDataSource(dynamicDataSource());
return sqlSessionFactoryBean;
}或者直接配置(不推薦該方式)：
@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
該異常在錯誤信息中已經說的很清楚了，是因為有多個
DataSource的實例，所以無法確定該引用那個實例
- 解決方法：
為數據源的某個
Bean添加@Primary注解，該Bean應當是通過DataSourceBuilder.create().build()
得到的Bean，而不是通過new AbstractRoutingDataSource的子類實現的Bean，在本項目中可以是master()
或slave()得到的DataSource，不能是dynamicDataSource()得到的DataSource
3. 通過注解方式動態切換數據源無效
- 請確認注解沒有放到 DAO 層方法上, 因為會在 Service 層開啟事務，所以當注解在 DAO 層時不會生效
- 請確認以下
Bean正確配置：
@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 注解無效，發生異常不回滾
- 請確認該
Bean得到正確配置，並且@Transactional的rollbackFor配置正確
@Bean
public PlatformTransactionManager transactionManager() {
return new DataSourceTransactionManager(dynamicDataSource());
}
5. 通過 AOP 判斷 DAO 層方法名時切換數據源無效
當切面指向了 DAO 層后無論如何設置切面的順序，都無法在執行查詢之前切換數據源，但是切面改為 Service 層后可以正常工作
解決方法: 請確認
@Transactional注解是加在方法上而不是 Service 類上，添加了@Transactional的方法因為在 Service 層開啟了事務，
會在事務結束之后才會切換數據源檢出
DataSourceTransactionManagerBean 注入正確
@Bean
public PlatformTransactionManager transactionManager() {
return new DataSourceTransactionManager(dynamicDataSource());
}6. The dependencies of some of the beans in the application context form a cycle
- 錯誤信息：
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
└─────┘
這是因為在注入
DataSource的實例的時候產生了循環調用，第一個注入的 Bean 依賴於其他的 Bean， 而被依賴的 Bean 產生依賴傳遞，依賴第一個
注入的 Bean, 陷入了循環，無法啟動項目
- 解決方法：將
@Primary注解指向沒有依賴的 Bean，如：
/**
* master DataSource
* @Primary 注解用於標識默認使用的 DataSource Bean，因為有三個 DataSource Bean，該注解可用於 master
* 或 slave DataSource Bean, 但不能用於 dynamicDataSource Bean, 否則會產生循環調用
* * @ConfigurationProperties 注解用於從 application.properties 文件中讀取配置，為 Bean 設置屬性
* @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;
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