springboot如何配置多个数据源呢?

配置多个数据源的实现思路

一、配置文件进行配置：
   1.导入依赖：
二、编写配置类：
   1.用来指定包扫描、指定sqlSessionTemplateRef
   2.用来指定mapper.xml的路径
   3.Mybatis主数据源ds1配置
   4.Mybatis第二个ds2数据源配置
  5.Mybatis第三个数据源配置

导入数据源连接所需的驱动

1.导入依赖：
  如 MySQL 和 PGSQL 
<dependency>
	<groupId>mysql</groupId>
	<artifactId>mysql-connector-java</artifactId>
	<scope>Runtime</scope>
</dependency>
 
<dependency>
    <groupId>org.postgresql</groupId>
    <artifactId>postgresql</artifactId>
    <version>42.2.7</version>
</dependency>

yml配置

spring:
 # 数据源配置
  datasource:
    ds1: #数据源1
      driver-class-name: com.mysql.jdbc.Driver # mysql的驱动你可以配置别的关系型数据库
      url: jdbc:mysql://ip:3306/db1 #数据源地址
      username: root # 用户名
      password: root # 密码
    ds2: # 数据源2
      driver-class-name: com.mysql.jdbc.Driver # mysql的驱动你可以配置别的关系型数据库
      url: jdbc:mysql://ip:3307/db2#数据源地址
      username: root # 用户名
      password: root # 密码

编写配置类

编写Springboot的配置类：

mybatis多数据源切换的原理
   根据不同包
    调用不同的数据源
     将mapper.java和mapper.xml 写在某个package中
    springboot自动帮你实现数据源切换。
 
//指定包扫描
//指定sqlSessionTemplateRef
@MapperScan(basePackages ="com.web.ds2.**.dao", 
            sqlSessionTemplateRef = "ds2SqlSessionTemplate")

//用来指定mapper.xml的路径
sqlSessionFactory.
    setMapperLocations(new PathMatchingResourcePatternResolver().
                                getResources("classpath*:com/web/ds2/**/*.xml"));

Mybatis主数据源ds1配置

/**
 * Mybatis主数据源ds1配置
 * 多数据源配置依赖数据源配置
 *  DataSourceConfig
 */
@Configuration
@MapperScan(basePackages ="com.web.ds1.**.dao", sqlSessionTemplateRef  = "ds1SqlSessionTemplate")
public class MybatisPlusConfig4ds1 {
 
    @Bean(name = "dataSource1")
    @ConfigurationProperties(prefix = "spring.datasource.ds1")
    @Primary
    public DataSource dataSource() {
        return DataSourceBuilder.create().build();
    }
 
    //主数据源 ds1数据源
    @Primary
    @Bean("ds1SqlSessionFactory")
    public SqlSessionFactory ds1SqlSessionFactory(@Qualifier("ds1DataSource") DataSource dataSource) throws Exception {
        MybatisSqlSessionFactoryBean sqlSessionFactory = new MybatisSqlSessionFactoryBean();
        sqlSessionFactory.setDataSource(dataSource);
        sqlSessionFactory.setMapperLocations(new PathMatchingResourcePatternResolver().
                        getResources("classpath*:com/web/ds1/**/*.xml"));  
        return sqlSessionFactory.getObject();
    }
 
    @Primary
    @Bean(name = "ds1TransactionManager")
    public DataSourceTransactionManager ds1TransactionManager(@Qualifier("ds1DataSource") DataSource dataSource) {
        return new DataSourceTransactionManager(dataSource);
    }
 
    @Primary
    @Bean(name = "ds1SqlSessionTemplate")
    public SqlSessionTemplate ds1SqlSessionTemplate(@Qualifier("ds1SqlSessionFactory") SqlSessionFactory sqlSessionFactory) {
        return new SqlSessionTemplate(sqlSessionFactory);
    }
 
}

Mybatis第二个ds2数据源配置

/**
 * Mybatis  第二个ds2数据源配置
 * 多数据源配置依赖数据源配置
 * @see  DataSourceConfig
 */
@Configuration
@MapperScan(basePackages ="com.web.ds2.**.dao", sqlSessionTemplateRef  = "ds2SqlSessionTemplate")
public class MybatisPlusConfig4ds2 {
 
    @Bean(name = "dataSource2")
    @ConfigurationProperties(prefix = "spring.datasource.ds2")
    public DataSource dataSource() {
        return DataSourceBuilder.create().build();
    }
 
    //ds2数据源
    @Bean("ds2SqlSessionFactory")
    public SqlSessionFactory ds2SqlSessionFactory(@Qualifier("ds2DataSource") DataSource dataSource) throws Exception {
        MybatisSqlSessionFactoryBean sqlSessionFactory = new MybatisSqlSessionFactoryBean();
        sqlSessionFactory.setDataSource(dataSource);
        sqlSessionFactory.setMapperLocations(new PathMatchingResourcePatternResolver().
                getResources("classpath*:com/web/ds2/**/*.xml"));
        return sqlSessionFactory.getObject();
    }
 
    //事务支持
    @Bean(name = "ds2TransactionManager")
    public DataSourceTransactionManager ds2TransactionManager(@Qualifier("ds2DataSource") DataSource dataSource) {
        return new DataSourceTransactionManager(dataSource);
    }
 
    @Bean(name = "ds2SqlSessionTemplate")
    public SqlSessionTemplate ds2SqlSessionTemplate(@Qualifier("ds2SqlSessionFactory") SqlSessionFactory sqlSessionFactory) {
        return new SqlSessionTemplate(sqlSessionFactory);
    }
 
}

Mybatis第三个数据源配置（另一种配置方法

有DataSourceTransactionManager 事务管理

import com.baomidou.mybatisplus.core.MybatisConfiguration;
import com.baomidou.mybatisplus.extension.spring.MybatisSqlSessionFactoryBean;
import org.apache.ibatis.session.SqlSessionFactory;
import org.mybatis.spring.SqlSessionTemplate;
import org.mybatis.spring.annotation.MapperScan;
import org.springframework.beans.factory.annotation.Qualifier;
import org.springframework.boot.context.properties.ConfigurationProperties;
import org.springframework.boot.jdbc.DataSourceBuilder;
import org.springframework.context.annotation.Bean;
import org.springframework.context.annotation.Configuration;
import org.springframework.context.annotation.Primary;
import org.springframework.core.io.support.PathMatchingResourcePatternResolver;
import org.springframework.data.jpa.repository.config.EnableJpaRepositories;
import org.springframework.jdbc.datasource.DataSourceTransactionManager;
 
import javax.sql.DataSource;
 
@Configuration
@EnableJpaRepositories({"xxx.xxx.xx.xx.xx"})
@MapperScan(basePackages = {"xx.xx.xx.xx.xx.xx"}, sqlSessionFactoryRef = "sqlSessionFactory")
public class PrimaryDataSourceConfig {
 
    @Bean
    @ConfigurationProperties(prefix = "mybatis-plus.configuration")
    public MybatisConfiguration globalConfiguration() {
        return new MybatisConfiguration();
    }
 
    @Bean(name = "dataSource")
    @ConfigurationProperties(prefix = "spring.datasource.primary")
    @Primary
    public DataSource dataSource() {
        return DataSourceBuilder.create().build();
    }
 
    @Bean(name = "sqlSessionFactory")
    @Primary
    public SqlSessionFactory sqlSessionFactory(@Qualifier("dataSource") DataSource dataSource) throws Exception {
        MybatisSqlSessionFactoryBean bean = new MybatisSqlSessionFactoryBean();
        bean.setDataSource(dataSource);
        //这里将下划线映射为驼峰的配置引入
        bean.setConfiguration(globalConfiguration());
        bean.setMapperLocations(new PathMatchingResourcePatternResolver().getResources("classpath:mappers/*.xml"));
        return bean.getObject();
    }
 
    @Bean(name = "transactionManager")
    @Primary
    public DataSourceTransactionManager transactionManager(@Qualifier("dataSource") DataSource dataSource) {
        return new DataSourceTransactionManager(dataSource);
    }
 
    @Bean(name = "sqlSessionTemplate")
    @Primary
    public SqlSessionTemplate sqlSessionTemplate(@Qualifier("sqlSessionFactory") SqlSessionFactory sqlSessionFactory) {
        return new SqlSessionTemplate(sqlSessionFactory);
    }
}

Service层：
@Service
public class TestService {
 
    @Resource
    private ClusterMapper clusterMapper;
    @Resource
    private MasterMapper masterMapper;
 
    public list<HashMap<String, Object>> queryBooks() {
        return masterMapper.queryBooks(); //指定的配置类扫描的是一个包
    }
 
    public List<HashMap<String, Object>> queryOrders() {
        return clusterMapper.queryOrders(); //指定的配置类扫描的是另一个包
    }
} 

Controller层：
@RestController
@RequestMapping(value = "/test", method = RequestMethod.POST)
public class TestController {
    @Resource
    private TestService testService;
 
    @RequestMapping("/books")
    public List<HashMap<String, Object>> queryBooks() {
        return testService.queryBooks();
    }
 
    @RequestMapping("/orders")
    public List<HashMap<String, Object>> queryOrders() {
        return testService.queryOrders();
    }
}