The introduction of mybatis and mysql in springboot will not be discussed here. If you don’t understand, you can refer to the introduction of mysql and mybatis in springboot.
The data source configuration is as follows:
datasource: master: type: com.alibaba.druid.pool.DruidDataSource jdbc-url: jdbc:mysql://127.0.0.1:3306/sbac_master?autoReconnect=true&useUnicode=true&characterEncoding=utf-8&zeroDateTimeBehavior=convertToNull&allowMultiQueries=true username: root password: 1234 driver-class-name: com.mysql.cj.jdbc.Driver log: type: com.alibaba.druid.pool.DruidDataSource jdbc-url: jdbc:mysql://127.0.0.1:3306/sbac_log?autoReconnect=true&useUnicode=true&characterEncoding=utf-8&zeroDateTimeBehavior=convertToNull&allowMultiQueries=true username: root password: 1234 driver-class-name: com.mysql.cj.jdbc.Driver
The configuration of mybatis is introduced as follows:
mybatis: config-location: classpath:mybatis-config.xml mapper-locations: classpath:com/lazycece/sbac/mysql/data/dao/*/mapper/*.xml
The automatic configuration function of springboot is already used here. Configuring mybatis information only manually specifies the data source. As shown below, two data sources, master and log, are specified, and master is set as the default data source:
@Configuration public class MultiDataSource { public static final String MASTER_DATA_SOURCE = "masterDataSource"; public static final String LOG_DATA_SOURCE = "logDataSource"; @Bean(name = MultiDataSource.MASTER_DATA_SOURCE) @ConfigurationProperties(prefix = "datasource.master") public DataSource masterDataSource() { return DataSourceBuilder.create().build(); } @Bean(name = MultiDataSource.LOG_DATA_SOURCE) @ConfigurationProperties(prefix = "datasource.log") public DataSource logDataSource() { return DataSourceBuilder.create().build(); } @Primary @Bean(name = "dynamicDataSource") public DynamicDataSource dataSource() { DynamicDataSource dynamicDataSource = new DynamicDataSource(); dynamicDataSource.setDefaultTargetDataSource(masterDataSource()); Map<Object, Object> dataSourceMap = new HashMap<>(4); dataSourceMap.put(MASTER_DATA_SOURCE, masterDataSource()); dataSourceMap.put(LOG_DATA_SOURCE, logDataSource()); dynamicDataSource.setTargetDataSources(dataSourceMap); return dynamicDataSource; } }
After introducing the configuration information , it’s time to talk about how to implement multi-data source switching. We implement the determineCurrentLookupKey method of the AbstractRoutingDataSource class to implement dynamic routing of the data source, and set the ThreadLocal thread protection variable to store the data source key to ensure that threads are not affected.
package com.lazycece.sbac.mysql.multi.config; import org.slf4j.Logger; import org.slf4j.LoggerFactory; import org.springframework.jdbc.datasource.lookup.AbstractRoutingDataSource; /** * @author lazycece */ public class DynamicDataSource extends AbstractRoutingDataSource { private static final Logger LOGGER = LoggerFactory.getLogger(DynamicDataSource.class); private static final ThreadLocal<String> DATA_SOURCE_KEY = new ThreadLocal<>(); static void changeDataSource(String dataSourceKey) { DATA_SOURCE_KEY.set(dataSourceKey); } static void clearDataSource() { DATA_SOURCE_KEY.remove(); } @Override protected Object determineCurrentLookupKey() { String key = DATA_SOURCE_KEY.get(); LOGGER.info("current data-source is {}", key); return key; } }
Then, AOP is used to implement dynamic switching of data sources. The annotations and aspects are defined as follows:
@Documented @Inherited @Retention(RetentionPolicy.RUNTIME) @Target({ElementType.METHOD, ElementType.TYPE}) public @interface DataSource { String value(); } @Component @Aspect public class DataSourceConfig { @Before("@annotation(dataSource)") public void beforeSwitchDataSource(DataSource dataSource) { DynamicDataSource.changeDataSource(dataSource.value()); } @After("@annotation(DataSource)") public void afterSwitchDataSource() { DynamicDataSource.clearDataSource(); } }
Dynamic data source switching only needs to use the @DataSource annotation in the business to indicate the data source to be used, as shown below (only the key code is posted here):
@Service public class DynamicDataSourceServiceImpl implements DynamicDataSourceService { @Resource private UserDao userDao; @Resource private SystemLogDao systemLogDao; @Override @DataSource(value = MultiDataSource.MASTER_DATA_SOURCE) public void addUserInfo(User user) { userDao.insert(user); } @Override @DataSource(value = MultiDataSource.MASTER_DATA_SOURCE) public User getUserInfo(String username) { return userDao.findByUsername(username); } @Override @DataSource(value = MultiDataSource.LOG_DATA_SOURCE) public void addSystemLog(SystemLog systemLog) { systemLogDao.insert(systemLog); } @Override @DataSource(value = MultiDataSource.LOG_DATA_SOURCE) public List<SystemLog> getSystemLogInfo(Date beginTime, Date endTime) { return systemLogDao.findByCreateTime(beginTime, endTime); } }
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