spring boot 本身自带对数据源的支持。 但在项目开发过程中，存在这种情况需要用到多数据源，用spring boot 自带的数据源就不是那么方便了。这里有个实例实现spring boot 完成多数据源的配置。

项目的目录结构是这样的。

下面看看数据源配置

// 主数据源配置
package com.tansun.beanconfig.datasourse;import java.util.Properties;import javax.sql.DataSource;import org.apache.ibatis.mapping.DatabaseIdProvider;
import org.apache.ibatis.mapping.VendorDatabaseIdProvider;
import org.apache.ibatis.session.SqlSessionFactory;
import org.mybatis.spring.SqlSessionFactoryBean;
import org.mybatis.spring.SqlSessionTemplate;
import org.mybatis.spring.annotation.MapperScan;
import org.springframework.beans.factory.annotation.Qualifier;
import org.springframework.beans.factory.annotation.Value;
import org.springframework.boot.autoconfigure.EnableAutoConfiguration;
import org.springframework.context.annotation.Bean;
import org.springframework.context.annotation.Configuration;
import org.springframework.context.annotation.Primary;
import org.springframework.jdbc.datasource.DataSourceTransactionManager;import com.alibaba.druid.pool.DruidDataSource;/*** 注：主程序使用数据源* @author kangx**/
@Configuration
@EnableAutoConfiguration
@MapperScan(basePackages = MainDSConfig.PACKAGE, sqlSessionTemplateRef = "masterSqlSessionTemplate")
public class MainDSConfig {// 精确到 master 目录，以便跟其他数据源隔离，不同数据源扫描的mapper// 文件地址是不一样的，如果放到统一路径启动会报生成bean冲突。static final String PACKAGE = "com.tansun.model.*.mapper";static final String MAPPER_LOCATION = "classpath:com/tansun/model/*/master/*.xml";@Value("${spring.datasource.url}")private String url;@Value("${spring.datasource.username}")private String user;@Value("${spring.datasource.password}")private String password;@Value("${spring.datasource.driver-class-name}")private String driverClass;/*** 注：主数据源加@Primary 注解 表示当系统有多个datasource 满足条件，* 默认使用@Primary标记的数据源* @return*/@Bean(name = "masterDataSource")@Primarypublic DataSource masterDataSource() {DruidDataSource dataSource = new DruidDataSource();dataSource.setDriverClassName(driverClass);dataSource.setUrl(url);dataSource.setDbType("oracle");dataSource.setUsername(user);dataSource.setPassword(password);return dataSource;}@Bean(name = "masterTransactionManager")@Primarypublic DataSourceTransactionManager masterTransactionManager() {return new DataSourceTransactionManager(masterDataSource());}@Bean(name = "masterSqlSessionFactory")@Primarypublic SqlSessionFactory masterSqlSessionFactory(@Qualifier("masterDataSource") DataSource masterDataSource,@Qualifier("databaseIdProvider") DatabaseIdProvider databaseIdProvider)throws Exception {final SqlSessionFactoryBean sessionFactory = new SqlSessionFactoryBean();sessionFactory.setDataSource(masterDataSource);sessionFactory.setDatabaseIdProvider(databaseIdProvider);return sessionFactory.getObject();}@Bean(name = "masterSqlSessionTemplate")public SqlSessionTemplate outerSqlSessionTemplate(@Qualifier("masterSqlSessionFactory") SqlSessionFactory sqlSessionFactory) throws Exception {return new SqlSessionTemplate(sqlSessionFactory);}@Bean("databaseIdProvider")public DatabaseIdProvider getDatabaseIdProvider() {DatabaseIdProvider databaseIdProvider = new VendorDatabaseIdProvider();Properties pro = new Properties();pro.setProperty("Oracle", "oracle");pro.setProperty("MySQL", "mysql");databaseIdProvider.setProperties(pro);return databaseIdProvider;}}

// 从数据源配置

package com.tansun.beanconfig.datasourse;import java.util.Properties;import javax.sql.DataSource;import org.apache.ibatis.mapping.DatabaseIdProvider;
import org.apache.ibatis.mapping.VendorDatabaseIdProvider;
import org.apache.ibatis.session.SqlSessionFactory;
import org.mybatis.spring.SqlSessionFactoryBean;
import org.mybatis.spring.SqlSessionTemplate;
import org.mybatis.spring.annotation.MapperScan;
import org.springframework.beans.factory.annotation.Qualifier;
import org.springframework.beans.factory.annotation.Value;
import org.springframework.boot.autoconfigure.EnableAutoConfiguration;
import org.springframework.context.annotation.Bean;
import org.springframework.context.annotation.Configuration;
import org.springframework.context.annotation.Import;
import org.springframework.jdbc.datasource.DataSourceTransactionManager;import com.alibaba.druid.pool.DruidDataSource;
/*** 注：定时任务使用数据源* @author kangx*/
@Configuration
@EnableAutoConfiguration
// import 表示引用主数据源的配置bean
@Import(value = { MainDSConfig.class })
@MapperScan(basePackages = RunTaskDSConfig.PACKAGE, sqlSessionTemplateRef = "runtaskSqlSessionTemplate")
public class RunTaskDSConfig {// 精确到 master 目录，以便跟其他数据源隔离--这儿扫描的地址和主数据地址//不同static final String PACKAGE = "com.tansun.taskmodel.*.mapper";static final String MAPPER_LOCATION = "classpath:com/tansun/taskmodel/*/master/*.xml";@Value("${runtask.datasource.url}")private String url;@Value("${runtask.datasource.username}")private String user;@Value("${runtask.datasource.password}")private String password;@Value("${runtask.datasource.driverClassName}")private String driverClass;@Bean(name = "runtaskDataSource")public DataSource masterDataSource() {DruidDataSource dataSource = new DruidDataSource();dataSource.setDriverClassName(driverClass);dataSource.setUrl(url);dataSource.setUsername(user);dataSource.setDbType("mysql");dataSource.setPassword(password);return dataSource;}@Bean(name = "runtaskTransactionManager")public DataSourceTransactionManager masterTransactionManager() {return new DataSourceTransactionManager(masterDataSource());}@Bean(name = "runtaskSqlSessionFactory")public SqlSessionFactory masterSqlSessionFactory(@Qualifier("runtaskDataSource") DataSource masterDataSource,@Qualifier("databaseIdProvider") DatabaseIdProvider databaseIdProvider)throws Exception {final SqlSessionFactoryBean sessionFactory = new SqlSessionFactoryBean();sessionFactory.setDataSource(masterDataSource);sessionFactory.setDatabaseIdProvider(databaseIdProvider);return sessionFactory.getObject();}@Bean(name = "runtaskSqlSessionTemplate")public SqlSessionTemplate outerSqlSessionTemplate(@Qualifier("runtaskSqlSessionFactory") SqlSessionFactory sqlSessionFactory) throws Exception {return new SqlSessionTemplate(sqlSessionFactory);}@Bean("runtaskDatabaseIdProvider")public DatabaseIdProvider getDatabaseIdProvider() {DatabaseIdProvider databaseIdProvider = new VendorDatabaseIdProvider();Properties pro = new Properties();pro.setProperty("Oracle", "oracle");pro.setProperty("MySQL", "mysql");databaseIdProvider.setProperties(pro);return databaseIdProvider;}
}

注 ：
1主数据源配置 bean 上加@Primary标签，表示当找多个符合的匹配时，使用由 primary 标记的bean。 如果不加Primary标签启动会报错。
2 runtaskDatabaseIdProvider -> bean 配置是为了设置数据库兼容的设置。该处设置的值可以在， mapper文件中取到，用于标记不同的数据库，这一过程是有spring-mybatis 底层操作完成的。

数据源配置属性文件
所在路径

#数据库配置
spring.datasource.driver-class-name=
spring.datasource.url=
spring.datasource.username=
spring.datasource.password=
spring.jpa.show-sql=true#定时任务数据源配置
#runtask.datasource.url=jdbc:mysql://localhost:3306/student?useUnicode=true&characterEncoding=utf8
#runtask.datasource.username=root
#runtask.datasource.password=root
#runtask.datasource.driverClassName=com.mysql.jdbc.Driver
runtask.datasource.driverClassName=
runtask.datasource.url=
runtask.datasource.username=
runtask.datasource.password=
runtask.jpa.show-sql=true