参考网址:https://www.cnblogs.com/java-zhao/p/5413845.html
1.配置文件application.properties中增加其他数据源设置
#the first datasource
jdbc.driverClassName = com.mysql.jdbc.Driver
jdbc.url = jdbc:mysql://xxx:3306/mytestdb?zeroDateTimeBehavior=convertToNull&useUnicode=true&characterEncoding=utf-8
jdbc.username = root
jdbc.password = 123
#the second datasource
jdbc2.driverClassName = com.mysql.jdbc.Driver
jdbc2.url = jdbc:mysql://xxx:3306/mytestdb2?zeroDateTimeBehavior=convertToNull&useUnicode=true&characterEncoding=utf-8
jdbc2.username = root
jdbc2.password = 123
2.建立databaseType枚举类,列举数据源的key
package com.xxx.firstboot.common.datasource; /** * 列出所有的数据源key(常用数据库名称来命名) * 注意: * 1)这里数据源与数据库是一对一的 * 2)DatabaseType中的变量名称就是数据库的名称 */ public enum DatabaseType { mytestdb,mytestdb2 }
3.DatabaseContextHolder构建DatabaseType容器,并提供了向其中设置和获取DatabaseType的方法
package com.xxx.firstboot.common.datasource; /** * 作用: * 1、保存一个线程安全的DatabaseType容器 */ public class DatabaseContextHolder { private static final ThreadLocal<DatabaseType> contextHolder = new ThreadLocal<>(); public static void setDatabaseType(DatabaseType type){ contextHolder.set(type); } public static DatabaseType getDatabaseType(){ return contextHolder.get(); } }
4.建立DynamicDataSource类,使用DatabaseContextHolder获取当前线程的DatabaseType
package com.xxx.firstboot.common.datasource; import org.springframework.jdbc.datasource.lookup.AbstractRoutingDataSource; /** * 动态数据源(需要继承AbstractRoutingDataSource) */ public class DynamicDataSource extends AbstractRoutingDataSource { protected Object determineCurrentLookupKey() { return DatabaseContextHolder.getDatabaseType(); } }
5.配置MyBatisConfig,通过application.properties文件生成两个数据源,使用这两个数据源构造动态的dataSource
@Primary:指定在同一个接口有多个实现类可以注入的时候,默认选择哪一个
@Qualifier:指定名称的注入,当一个接口有多个实现类时使用
@Bean:生成的bean示例的名称
package com.xxx.firstboot.common; import java.util.HashMap; import java.util.Map; import java.util.Properties; import javax.sql.DataSource; import org.apache.ibatis.session.SqlSessionFactory; import org.mybatis.spring.SqlSessionFactoryBean; import org.mybatis.spring.annotation.MapperScan; import org.springframework.beans.factory.annotation.Autowired; import org.springframework.beans.factory.annotation.Qualifier; import org.springframework.context.annotation.Bean; import org.springframework.context.annotation.Configuration; import org.springframework.context.annotation.Primary; import org.springframework.core.env.Environment; import org.springframework.core.io.support.PathMatchingResourcePatternResolver; import org.springframework.jdbc.datasource.DataSourceTransactionManager; import com.alibaba.druid.pool.DruidDataSourceFactory; import com.xxx.firstboot.common.datasource.DatabaseType; import com.xxx.firstboot.common.datasource.DynamicDataSource; /** * springboot集成mybatis的基本入口 1)创建数据源(如果采用的是默认的tomcat-jdbc数据源,则不需要) * 2)创建SqlSessionFactory 3)配置事务管理器,除非需要使用事务,否则不用配置 */ @Configuration // 该注解类似于spring配置文件 @MapperScan(basePackages = "com.xxx.firstboot.mapper") public class MyBatisConfig { @Autowired private Environment env; /** * 创建数据源(数据源的名称:方法名可以取为XXXDataSource(),XXX为数据库名称,该名称也就是数据源的名称) */ @Bean public DataSource myTestDbDataSource() throws Exception { Properties props = new Properties(); props.put("driverClassName", env.getProperty("jdbc.driverClassName")); props.put("url", env.getProperty("jdbc.url")); props.put("username", env.getProperty("jdbc.username")); props.put("password", env.getProperty("jdbc.password")); return DruidDataSourceFactory.createDataSource(props); } @Bean public DataSource myTestDb2DataSource() throws Exception { Properties props = new Properties(); props.put("driverClassName", env.getProperty("jdbc2.driverClassName")); props.put("url", env.getProperty("jdbc2.url")); props.put("username", env.getProperty("jdbc2.username")); props.put("password", env.getProperty("jdbc2.password")); return DruidDataSourceFactory.createDataSource(props); } /** * @Primary 该注解表示在同一个接口有多个实现类可以注入的时候,默认选择哪一个,而不是让@autowire注解报错 * @Qualifier 根据名称进行注入,通常是在具有相同的多个类型的实例的一个注入(例如有多个DataSource类型的实例) */ @Bean @Primary public DynamicDataSource dataSource(@Qualifier("myTestDbDataSource") DataSource myTestDbDataSource, @Qualifier("myTestDb2DataSource") DataSource myTestDb2DataSource) { Map<Object, Object> targetDataSources = new HashMap<>(); targetDataSources.put(DatabaseType.mytestdb, myTestDbDataSource); targetDataSources.put(DatabaseType.mytestdb2, myTestDb2DataSource); DynamicDataSource dataSource = new DynamicDataSource(); dataSource.setTargetDataSources(targetDataSources);// 该方法是AbstractRoutingDataSource的方法 dataSource.setDefaultTargetDataSource(myTestDbDataSource);// 默认的datasource设置为myTestDbDataSource return dataSource; } /** * 根据数据源创建SqlSessionFactory */ @Bean public SqlSessionFactory sqlSessionFactory(DynamicDataSource ds) throws Exception { SqlSessionFactoryBean fb = new SqlSessionFactoryBean(); fb.setDataSource(ds);// 指定数据源(这个必须有,否则报错) // 下边两句仅仅用于*.xml文件,如果整个持久层操作不需要使用到xml文件的话(只用注解就可以搞定),则不加 fb.setTypeAliasesPackage(env.getProperty("mybatis.typeAliasesPackage"));// 指定基包 fb.setMapperLocations( new PathMatchingResourcePatternResolver().getResources(env.getProperty("mybatis.mapperLocations")));// return fb.getObject(); } /** * 配置事务管理器 */ @Bean public DataSourceTransactionManager transactionManager(DynamicDataSource dataSource) throws Exception { return new DataSourceTransactionManager(dataSource); } }
6.使用实例
package com.xxx.firstboot.web; import org.springframework.beans.factory.annotation.Autowired; import org.springframework.web.bind.annotation.RequestMapping; import org.springframework.web.bind.annotation.RequestMethod; import org.springframework.web.bind.annotation.RequestParam; import org.springframework.web.bind.annotation.RestController; import com.xxx.firstboot.domain.Shop; import com.xxx.firstboot.service.ShopService; import io.swagger.annotations.Api; import io.swagger.annotations.ApiOperation; @RestController @RequestMapping("/shop") @Api("shopController相关api") public class ShopController { @Autowired private ShopService service; @ApiOperation("获取shop信息,测试多数据源") @RequestMapping(value = "/getShop", method = RequestMethod.GET) public Shop getShop(@RequestParam("id") int id) { return service.getShop(id); } }
package com.xxx.firstboot.service; import org.springframework.beans.factory.annotation.Autowired; import org.springframework.stereotype.Service; import com.xxx.firstboot.dao.ShopDao; import com.xxx.firstboot.domain.Shop; @Service public class ShopService { @Autowired private ShopDao dao; public Shop getShop(int id) { return dao.getShop(id); } }
package com.xxx.firstboot.dao; import org.springframework.beans.factory.annotation.Autowired; import org.springframework.stereotype.Repository; import com.xxx.firstboot.common.datasource.DatabaseContextHolder; import com.xxx.firstboot.common.datasource.DatabaseType; import com.xxx.firstboot.domain.Shop; import com.xxx.firstboot.mapper.ShopMapper; @Repository public class ShopDao { @Autowired private ShopMapper mapper; /** * 获取shop */ public Shop getShop(int id) { DatabaseContextHolder.setDatabaseType(DatabaseType.mytestdb2); return mapper.getShop(id); } }
package com.xxx.firstboot.mapper; import org.apache.ibatis.annotations.Param; import org.apache.ibatis.annotations.Result; import org.apache.ibatis.annotations.Results; import org.apache.ibatis.annotations.Select; import com.xxx.firstboot.domain.Shop; public interface ShopMapper { @Select("SELECT * FROM t_shop WHERE id = #{id}") @Results(value = { @Result(id = true, column = "id", property = "id"), @Result(column = "shop_name", property = "shopName") }) public Shop getShop(@Param("id") int id); }
7.通过AOP实现数据源切换
package com.xxx.firstboot.dao; import org.springframework.beans.factory.annotation.Autowired; import org.springframework.stereotype.Repository; import com.xxx.firstboot.domain.Shop; import com.xxx.firstboot.mapper.ShopMapper; @Repository public class ShopDao { @Autowired private ShopMapper mapper; /** * 获取shop */ public Shop getShop(int id) { return mapper.getShop(id); } }
package com.xxx.firstboot.common.datasource; import org.aspectj.lang.JoinPoint; import org.aspectj.lang.annotation.Aspect; import org.aspectj.lang.annotation.Before; import org.springframework.stereotype.Component; import com.xxx.firstboot.dao.ShopDao; @Aspect @Component public class DataSourceAspect { @Before("execution(* com.xxx.firstboot.dao.*.*(..))") public void setDataSourceKey(JoinPoint point){ //连接点所属的类实例是ShopDao if(point.getTarget() instanceof ShopDao){ DatabaseContextHolder.setDatabaseType(DatabaseType.mytestdb2); }else{//连接点所属的类实例是UserDao(当然,这一步也可以不写,因为defaultTargertDataSource就是该类所用的mytestdb) DatabaseContextHolder.setDatabaseType(DatabaseType.mytestdb); } } // @Around("execution(* com.xxx.firstboot.dao.*.*(..))") // public Object setDataSourceKeyByAround(ProceedingJoinPoint point) throws Throwable{ // if(point.getTarget() instanceof ShopDao){ // DatabaseContextHolder.setDatabaseType(DatabaseType.mytestdb2); // }else{//连接点所属的类实例是UserDao(当然,这一步也可以不写,因为defaultTargertDataSource就是该类所用的mytestdb) // DatabaseContextHolder.setDatabaseType(DatabaseType.mytestdb); // } // return point.proceed();//执行目标方法 // } }
或者
package com.xxx.firstboot.common.datasource; import org.aspectj.lang.JoinPoint; import org.aspectj.lang.annotation.Aspect; import org.aspectj.lang.annotation.Before; import org.aspectj.lang.annotation.Pointcut; import org.springframework.stereotype.Component; import com.xxx.firstboot.dao.ShopDao; @Aspect @Component public class DataSourceAspect { /** * 使用空方法定义切点表达式 */ @Pointcut("execution(* com.xxx.firstboot.dao.*.*(..))") public void declareJointPointExpression() { } /** * 使用定义切点表达式的方法进行切点表达式的引入 */ @Before("declareJointPointExpression()") public void setDataSourceKey(JoinPoint point) { // 连接点所属的类实例是ShopDao if (point.getTarget() instanceof ShopDao) { DatabaseContextHolder.setDatabaseType(DatabaseType.mytestdb2); } else {// 连接点所属的类实例是UserDao(当然,这一步也可以不写,因为defaultTargertDataSource就是该类所用的mytestdb) DatabaseContextHolder.setDatabaseType(DatabaseType.mytestdb); } } }