springboot+mybatis多数据源

在Spring Boot中使用MyBatis实现多数据源配置，可以通过以下步骤实现：

1. 在`application.properties`文件中配置多个数据源的连接信息，例如：

# 数据源1
spring.datasource.primary.url=jdbc:mysql://localhost:3306/db1
spring.datasource.primary.username=user1
spring.datasource.primary.password=pass1
spring.datasource.primary.driver-class-name=com.mysql.jdbc.Driver

# 数据源2
spring.datasource.secondary.url=jdbc:mysql://localhost:3306/db2
spring.datasource.secondary.username=user2
spring.datasource.secondary.password=pass2
spring.datasource.secondary.driver-class-name=com.mysql.jdbc.Driver

2. 创建多个数据源的配置类，分别继承`org.springframework.boot.autoconfigure.jdbc.DataSourceProperties`类，并使用`@ConfigurationProperties`注解来注入对应的配置信息，例如：

@Configuration
public class PrimaryDataSourceConfig extends DataSourceProperties {
    @Bean
    @Primary
    public DataSource dataSource() {
        return createDataSource();
    }

    private DataSource createDataSource() {
        return DataSourceBuilder.create().url(getUrl())
                .username(getUsername()).password(getPassword())
                .driverClassName(getDriverClassName()).build();
    }
}

@Configuration
public class SecondaryDataSourceConfig extends DataSourceProperties {
    @Bean
    public DataSource dataSource() {
        return createDataSource();
    }

    private DataSource createDataSource() {
        return DataSourceBuilder.create().url(getUrl())
                .username(getUsername()).password(getPassword())
                .driverClassName(getDriverClassName()).build();
    }
}

3. 创建多个`SqlSessionFactory`，并分别注入对应的数据源，例如：

@Configuration
@MapperScan(basePackages = "com.example.mapper.primary", sqlSessionFactoryRef = "primarySqlSessionFactory")
public class PrimaryMyBatisConfig {
    @Bean
    @Primary
    public SqlSessionFactory primarySqlSessionFactory(@Qualifier("primaryDataSource") DataSource dataSource) throws Exception {
        SqlSessionFactoryBean sessionFactoryBean = new SqlSessionFactoryBean();
        sessionFactoryBean.setDataSource(dataSource);
        return sessionFactoryBean.getObject();
    }
}

@Configuration
@MapperScan(basePackages = "com.example.mapper.secondary", sqlSessionFactoryRef = "secondarySqlSessionFactory")
public class SecondaryMyBatisConfig {
    @Bean
    public SqlSessionFactory secondarySqlSessionFactory(@Qualifier("secondaryDataSource") DataSource dataSource) throws Exception {
        SqlSessionFactoryBean sessionFactoryBean = new SqlSessionFactoryBean();
        sessionFactoryBean.setDataSource(dataSource);
        return sessionFactoryBean.getObject();
    }
}

4. 在`Mapper`接口上使用`@Qualifier`注解指定对应的`SqlSessionFactory`，例如：

@Mapper
public interface PrimaryUserMapper {
    @Select("SELECT * FROM user")
    @Results(id = "userMap", value = {
            @Result(property = "id", column = "id"),
            @Result(property = "name", column = "name")
    })
    List<User> findAll();

    @Insert("INSERT INTO user(name) VALUES(#{name})")
    @Options(useGeneratedKeys = true, keyProperty = "id")
    void save(User user);
}

@Mapper
public interface SecondaryUserMapper {
    @Select("SELECT * FROM user")
    @Results(id = "userMap", value = {
            @Result(property = "id", column = "id"),
            @Result(property = "name", column = "name")
    })
    List<User> findAll();

    @Insert("INSERT INTO user(name) VALUES(#{name})")
    @Options(useGeneratedKeys = true, keyProperty = "id")
    void save(User user);
}

这样就可以在同一个应用中使用多个数据源了。