一、配置文件

spring:
#  datasource:
#    username: root
#    password: 123456
#    url: jdbc:mysql://127.0.0.1:3306/jun01?characterEncoding=utf-8&serverTimezone=UTC
#    driver-class-name: com.mysql.cj.jdbc.Driver
  datasource:
    # 数据源1
    onedata:
      jdbc-url: jdbc:mysql://127.0.0.1:3306/jun01?useUnicode=true&characterEncoding=utf-8
      username: root
      password: 123456
      driver-class-name: com.mysql.cj.jdbc.Driver
    # 数据源2
    twodata:
      jdbc-url: jdbc:mysql://127.0.0.1:3306/jun02?useUnicode=true&characterEncoding=utf-8
      username: root
      password: 123456
      driver-class-name: com.mysql.cj.jdbc.Driver

二、数据源配置类

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 javax.sql.DataSource;

@Configuration
public class DataSourceConfiguration {

    // Primary 注解是在没有指明使用哪个数据源的时候指定默认使用的主数据源
    @Primary
    @Bean("oneDataSource")
    @ConfigurationProperties(prefix = "spring.datasource.onedata")
    public DataSource primaryDataSource() {
        return DataSourceBuilder.create().build();
    }

    @Bean("twoDataSource")
    @ConfigurationProperties(prefix = "spring.datasource.twodata")
    public DataSource secondaryDataSource() {
        return DataSourceBuilder.create().build();
    }
}

三、数据源与 Mybatis 配置

1、数据源一

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.context.annotation.Bean;
import org.springframework.context.annotation.Configuration;
import org.springframework.context.annotation.Primary;

import javax.annotation.Resource;
import javax.sql.DataSource;

@Configuration
// 指定该数据源扫描指定包下面的Mapper接口 与 *.xml文件
@MapperScan(
        basePackages = "com.south.mapper1",
        sqlSessionFactoryRef = "sqlSessionFactoryOne",
        sqlSessionTemplateRef = "sqlSessionTemplateOne")
public class DataSourceOneConfig {

    // 注入数据源1
    @Resource
    private DataSource oneDataSource;

    @Bean
    @Primary
    public SqlSessionFactory sqlSessionFactoryOne() throws Exception {
        SqlSessionFactoryBean sqlSessionFactoryBean = new SqlSessionFactoryBean();
        sqlSessionFactoryBean.setDataSource(oneDataSource);
        return sqlSessionFactoryBean.getObject();
    }

    @Bean
    @Primary
    public SqlSessionTemplate sqlSessionTemplateOne() throws Exception {
        return new SqlSessionTemplate(sqlSessionFactoryOne());
    }
}

2、数据源二（两种不同的配置方式,都能实现多数据源的效果）

import org.apache.ibatis.session.SqlSessionFactory;
import org.mybatis.spring.SqlSessionFactoryBean;
import org.mybatis.spring.annotation.MapperScan;
import org.springframework.context.annotation.Bean;
import org.springframework.context.annotation.Configuration;
import org.springframework.core.io.Resource;
import org.springframework.core.io.support.PathMatchingResourcePatternResolver;
import org.springframework.jdbc.datasource.DataSourceTransactionManager;

import javax.sql.DataSource;

@Configuration
@MapperScan(
        basePackages = "com.example.mapper2",
        sqlSessionFactoryRef = "sqlSessionFactoryTwo")
public class DataSourceTwoConfig {

    // mapper 扫描 xml 文件的路径
    private static final String MAPPER_LOCATION = "classpath:mapper2/*.xml";

    private DataSource twoDataSource;

    // 通过构造方法进行注入
    public DataSourceTwoConfig(DataSource dataSource) {
        this.twoDataSource = dataSource;
    }

    @Bean
    public SqlSessionFactory sqlSessionFactoryTwo() throws Exception {
        SqlSessionFactoryBean sqlSessionFactoryBean = new SqlSessionFactoryBean();
        // 指定数据源
        sqlSessionFactoryBean.setDataSource(twoDataSource);
        /*
		 * 获取xml文件资源对象
		 * 当Mapper接口所对应的.xml文件与Mapper接口文件分离,存储在 resources
		 * 文件夹下的时候,需要手动指定.xml文件所在的路径
		 */
        Resource[] resources = new PathMatchingResourcePatternResolver().getResources(MAPPER_LOCATION);
        sqlSessionFactoryBean.setMapperLocations(resources);
        return sqlSessionFactoryBean.getObject();
    }

    @Bean
    public DataSourceTransactionManager SecondaryDataSourceManager() {
        return new DataSourceTransactionManager(twoDataSource);
    }
}

四、使用案例

import org.springframework.stereotype.Controller;
import org.springframework.web.bind.annotation.GetMapping;
import org.springframework.web.bind.annotation.RequestMapping;
import org.springframework.web.bind.annotation.ResponseBody;

import javax.annotation.Resource;
import java.util.List;

@Controller
@RequestMapping("/testController")
public class TestController {

    // 数据源1Mapper注入
    @Resource
    private OneMapper oneMapper;

    // 数据源2Mapper注入
    @Resource
    private TwoMapper twoMapper;

    @GetMapping("/selectManyDataSouroneMapperceData")
    @ResponseBody
    public void selectManyDataSourceDatwoMapperta() {

        // 查询数据源1中的数据
        List<String> message = oneMapper.getMessage();
        System.out.println(message);

        // 查询数据源2中的数据
        List<String> tag = twoMapper.getTag();
        System.out.println(tag);
    }
}