springboot mybatis 同时连接mysql和sqlserver数据库

可以在Spring Boot项目中同时连接MySQL和SQL Server数据库，具体步骤如下：

1. 在pom.xml文件中添加MySQL和SQL Server数据库的驱动依赖，例如：

<dependency>
    <groupId>mysql</groupId>
    <artifactId>mysql-connector-java</artifactId>
    <version>${mysql.version}</version>
</dependency>

<dependency>
    <groupId>com.microsoft.sqlserver</groupId>
    <artifactId>mssql-jdbc</artifactId>
    <version>${sqlserver.version}</version>
</dependency>

2. 在application.yml文件中配置两个数据源，例如：

spring:
  datasource:
    primary:
      url: jdbc:mysql://localhost:3306/db_mysql
      driver-class-name: com.mysql.cj.jdbc.Driver
      username: root
      password: 123456

    secondary:
      url: jdbc:sqlserver://localhost:1433;databaseName=db_sqlserver
      driver-class-name: com.microsoft.sqlserver.jdbc.SQLServerDriver
      username: sa
      password: 123456

3. 在Spring Boot项目中配置两个数据源，例如：

@Configuration
public class DataSourceConfig {
    @Bean(name = "primaryDataSource")
    @Qualifier("primaryDataSource")
    @ConfigurationProperties(prefix = "spring.datasource.primary")
    public DataSource primaryDataSource() {
        return DataSourceBuilder.create().build();
    }

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

4. 在MyBatis中配置两个数据源，并指定使用哪个数据源，例如：

@Configuration
@MapperScan(basePackages = "com.example.mapper", sqlSessionTemplateRef = "primarySqlSessionTemplate")
public class MybatisConfig {
    @Bean(name = "primarySqlSessionFactory")
    @Primary
    public SqlSessionFactory primarySqlSessionFactory(@Qualifier("primaryDataSource") DataSource dataSource) throws Exception {
        SqlSessionFactoryBean bean = new SqlSessionFactoryBean();
        bean.setDataSource(dataSource);
        return bean.getObject();
    }

    @Bean(name = "secondarySqlSessionFactory")
    public SqlSessionFactory secondarySqlSessionFactory(@Qualifier("secondaryDataSource") DataSource dataSource) throws Exception {
        SqlSessionFactoryBean bean = new SqlSessionFactoryBean();
        bean.setDataSource(dataSource);
        return bean.getObject();
    }

    @Bean(name = "primarySqlSessionTemplate")
    @Primary
    public SqlSessionTemplate primarySqlSessionTemplate(@Qualifier("primarySqlSessionFactory") SqlSessionFactory sqlSessionFactory) throws Exception {
        return new SqlSessionTemplate(sqlSessionFactory);
    }

    @Bean(name = "secondarySqlSessionTemplate")
    public SqlSessionTemplate secondarySqlSessionTemplate(@Qualifier("secondarySqlSessionFactory") SqlSessionFactory sqlSessionFactory) throws Exception {
        return new SqlSessionTemplate(sqlSessionFactory);
    }

    @Bean
    @Primary
    public PlatformTransactionManager primaryTransactionManager(@Qualifier("primaryDataSource") DataSource dataSource) {
        return new DataSourceTransactionManager(dataSource);
    }

    @Bean
    public PlatformTransactionManager secondaryTransactionManager(@Qualifier("secondaryDataSource") DataSource dataSource) {
        return new DataSourceTransactionManager(dataSource);
    }
}

在定义Mapper时，可以通过@Qualifier注解指定使用哪个数据源的SqlSessionTemplate，例如：

public interface UserMapper {
    @Select("SELECT * FROM user")
    @Results({
            @Result(property = "id", column = "id"),
            @Result(property = "name", column = "name"),
            @Result(property = "age", column = "age")
    })
    List<User> getAllUsers();

    @Select("SELECT * FROM user WHERE id = #{id}")
    @Results({
            @Result(property = "id", column = "id"),
            @Result(property = "name", column = "name"),
            @Result(property = "age", column = "age")
    })
    User getUserById(@Param("id") Long id);
}

在Service层中，可以通过@Autowired注解注入UserMapper，并指定使用哪个数据源的SqlSessionTemplate，例如：

@Service
public class UserService {
    @Autowired
    @Qualifier("primarySqlSessionTemplate")
    private SqlSessionTemplate primarySqlSessionTemplate;

    @Autowired
    @Qualifier("secondarySqlSessionTemplate")
    private SqlSessionTemplate secondarySqlSessionTemplate;

    public List<User> getAllUsersFromPrimaryDataSource() {
        UserMapper userMapper = primarySqlSessionTemplate.getMapper(UserMapper.class);
        return userMapper.getAllUsers();
    }

    public User getUserByIdFromSecondaryDataSource(Long id) {
        UserMapper userMapper = secondarySqlSessionTemplate.getMapper(UserMapper.class);
        return userMapper.getUserById(id);
    }
}

这样就可以在Spring Boot项目中同时连接MySQL和SQL Server数据库了。