Spring多数据源管理方案

基于Spring的AbstractRoutingDataSource实现多数据源

数据库连接配置

spring:application:name: dynamic-sourcedatasource:datasource1:jdbc-url: jdbc:mysql://localhost:3306/cloud-demo?useUnicode=true&characterEncoding=utf-8&useSSL=falsedriver-class-name: com.mysql.cj.jdbc.Driverusername: rootpassword: rootinitialSize: 1maxActive: 20minIdle: 1maxWait: 60000datasource2:jdbc-url: jdbc:mysql://localhost:3306/foodie_dev?useUnicode=true&characterEncoding=utf-8&useSSL=falsedriver-class-name: com.mysql.cj.jdbc.Driverusername: rootpassword: rootinitialSize: 1maxActive: 20minIdle: 1maxWait: 60000

数据源配置

@Configuration
public class DataSourceConfig {@Bean@ConfigurationProperties(prefix = "spring.datasource.datasource1")public DataSource dataSource1() {// 根据配置 创建数据源实例return DataSourceBuilder.create().build();}@Bean@ConfigurationProperties(prefix = "spring.datasource.datasource2")public DataSource dataSource2() {return DataSourceBuilder.create().build();}}

继承AbstractRoutingDataSource，实现数据源切换逻辑

@Component
@Primary
public class DynamicDataSource extends AbstractRoutingDataSource {public static ThreadLocal<String> dataSourceKey = new ThreadLocal<>();@Autowiredprivate DataSource dataSource1;@Autowiredprivate DataSource dataSource2;/*** 决定使用哪个数据源之前需要调用这个方法来设置*/@Overrideprotected Object determineCurrentLookupKey() {return dataSourceKey.get();}@Overridepublic void afterPropertiesSet() {HashMap<Object, Object> targetDataSource = new HashMap<>();targetDataSource.put("W", dataSource1);targetDataSource.put("R", dataSource2);//设置数据源super.setTargetDataSources(targetDataSource);//设置默认数据源super.setDefaultTargetDataSource(dataSource1);super.afterPropertiesSet();}
}

在进行数据库操作时，切换到指定的数据源

@RestController
@RequestMapping("/test")
public class TestController {@Autowiredprivate AccountMapper accountManager;@RequestMapping("/account")public String selectAccount() {//查询clouded-demo数据库的account表DynamicDataSource.dataSourceKey.set("W");Account account = accountManager.selectByPrimaryKey(1);return account.toString();}@Autowiredprivate BookMapper bookMapper;@RequestMapping("/book")public String selectBook() {//查询foodie_dev数据库的book表DynamicDataSource.dataSourceKey.set("R");Book book = bookMapper.selectByPrimaryKey(1);return book.toString();}}

基于Mybatis实现多数据源

基于Mybatis实现多数据源管理，需要自己给每个数据源分别注册DataSource、SqlSessionFactory、
ataSourceTransactionManager

注册数据源1

@Configuration
@MapperScan(basePackages = "com.example.common.dao.w", sqlSessionFactoryRef = "wSqlSessionFactory")
public class WDataSourceConfig {@Bean@ConfigurationProperties(prefix = "spring.datasource.datasource1")public DataSource wDataSource() {return DataSourceBuilder.create().build();}@Bean@Primarypublic SqlSessionFactory wSqlSessionFactory(@Qualifier ("wDataSource") DataSource wDataSource) throws Exception {SqlSessionFactoryBean sqlSessionFactoryBean = new SqlSessionFactoryBean();//指定这个数据源要使用的mapper文件的位置sqlSessionFactoryBean.setMapperLocations(new PathMatchingResourcePatternResolver().getResources("classpath*:mappers/w/*.xml"));sqlSessionFactoryBean.setDataSource(wDataSource);return sqlSessionFactoryBean.getObject();}@Beanpublic DataSourceTransactionManager wDataSourceTransactionManager(@Qualifier ("wDataSource") DataSource wDataSource) {DataSourceTransactionManager transactionManager = new DataSourceTransactionManager();transactionManager.setDataSource(wDataSource);return transactionManager;}}

注册数据源2

@Configuration
@MapperScan(basePackages = "com.example.common.dao.r", sqlSessionFactoryRef = "rSqlSessionFactory")
public class RDataSourceConfig {@Bean@ConfigurationProperties(prefix = "spring.datasource.datasource2")public DataSource rDataSource() {return DataSourceBuilder.create().build();}@Beanpublic SqlSessionFactory rSqlSessionFactory(@Qualifier("rDataSource") DataSource rDataSource) throws Exception {SqlSessionFactoryBean sqlSessionFactoryBean = new SqlSessionFactoryBean();sqlSessionFactoryBean.setMapperLocations(new PathMatchingResourcePatternResolver().getResources("classpath*:mappers/r/*.xml"));sqlSessionFactoryBean.setDataSource(rDataSource);return sqlSessionFactoryBean.getObject();}@Beanpublic DataSourceTransactionManager rDataSourceTransactionManager(@Qualifier("rDataSource") DataSource rDataSource) {DataSourceTransactionManager transactionManager = new DataSourceTransactionManager();transactionManager.setDataSource(rDataSource);return transactionManager;}}

基于Mybatis实现的多数据源管理不需要在进行数据库操作时切换数据源，因为已经给不同的数据源维护了不同的SqlSessionFactory等组件。

使用dynamic-datasource框架

多数据源下的事务处理

在多数据源下，事务的处理成为了一个问题。因为可能需要对不同的库进行操作，那么这个时候就需要考虑事务问题了。如果一个业务中对两个库进行了操作，那么对这两个库的操作必须要同时失败或者同时成功。