SpringBoot整合Mybatis实现多数据源配置与跨数据源事务实例

关于“SpringBoot整合Mybatis实现多数据源配置与跨数据源事务实例”的完整攻略，我们可以分以下几个步骤来进行讲解：

1. 添加依赖：在 pom.xml 中添加多数据源、 Mybatis 等相关依赖，例如：

<!-- Spring Boot 多数据源依赖 -->
<dependency>
    <groupId>org.springframework.boot</groupId>
    <artifactId>spring-boot-starter-jdbc</artifactId>
</dependency>
<dependency>
     <groupId>com.zaxxer</groupId>
     <artifactId>HikariCP</artifactId>
</dependency>

<!-- MyBatis 依赖 -->
<dependency>
    <groupId>org.mybatis.spring.boot</groupId>
    <artifactId>mybatis-spring-boot-starter</artifactId>
</dependency>

1. 数据源配置：在 application.yml 中配置数据源信息，例如：

spring:
  datasource:
    master:
      url: jdbc:mysql://localhost:3306/db_master?useUnicode=true&characterEncoding=UTF-8&serverTimezone=Asia/Shanghai
      username: root
      password: root
      driver-class-name: com.mysql.cj.jdbc.Driver
    slave:
      url: jdbc:mysql://localhost:3306/db_slave?useUnicode=true&characterEncoding=UTF-8&serverTimezone=Asia/Shanghai
      username: root
      password: root
      driver-class-name: com.mysql.cj.jdbc.Driver

1. 配置 Mybatis：在 application.yml 中配置 Mybatis 相关信息，例如：

mybatis:
  mapper-locations: classpath:/mapper/*.xml
  configuration:
    map-underscore-to-camel-case: true

1. 多数据源配置：创建多数据源配置类，例如：

@Configuration
@MapperScan(basePackages = "com.example.mapper")
public class DataSourceConfig {
    @Bean(name = "masterDataSource")
    @ConfigurationProperties(prefix = "spring.datasource.master")
    public DataSource masterDataSource(){
        return DataSourceBuilder.create().build();
    }

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

    @Bean(name = "dynamicDataSource")
    public DataSource dynamicDataSource(@Qualifier("masterDataSource") DataSource masterDataSource,
                                         @Qualifier("slaveDataSource") DataSource slaveDataSource){
        DynamicRoutingDataSource dynamicRoutingDataSource = new DynamicRoutingDataSource();
        Map<Object, Object> dataSourceMap = new HashMap<>();
        dataSourceMap.put(DatabaseType.MASTER, masterDataSource);
        dataSourceMap.put(DatabaseType.SLAVE, slaveDataSource);
        dynamicRoutingDataSource.setDefaultTargetDataSource(masterDataSource);
        dynamicRoutingDataSource.setTargetDataSources(dataSourceMap);
        return dynamicRoutingDataSource;
    }
}

1. 配置事务：在需要跨多个数据源的事务方法上添加 @Transactional(rollbackFor = Exception.class) 注解，并创建 TransactionConfig 类进行事务管理，例如：

@Configuration
public class TransactionConfig {
    @Bean(name = "transactionManager")
    @Primary
    public DataSourceTransactionManager transactionManager(@Qualifier("dynamicDataSource") DataSource dynamicDataSource) {
        return new DataSourceTransactionManager(dynamicDataSource);
    }

    @Bean(name = "sqlSessionFactory")
    @Primary
    public SqlSessionFactory sqlSessionFactory(@Qualifier("dynamicDataSource") DataSource dynamicDataSource) throws Exception {
        SqlSessionFactoryBean sessionFactory = new SqlSessionFactoryBean();
        sessionFactory.setDataSource(dynamicDataSource);
        sessionFactory.setMapperLocations(new PathMatchingResourcePatternResolver().getResources("classpath:/mapper/**/*.xml"));
        return sessionFactory.getObject();
    }

    @Bean(name = "sqlSessionTemplate")
    @Primary
    public SqlSessionTemplate sqlSessionTemplate(@Qualifier("sqlSessionFactory") SqlSessionFactory sqlSessionFactory) {
        return new SqlSessionTemplate(sqlSessionFactory);
    }
}

至此，就完成了 SpringBoot 整合 Mybatis 实现多数据源配置与跨数据源事务实例的配置。

下面展示两个示例：

1. 多数据源查询

@Service
public class UserService {
    @Autowired
    private UserMapper userMapper;

    @Autowired
    private SlaveUserMapper slaveUserMapper;

    public List<User> getAllUsers() {
        List<User> users = userMapper.getAllUsers();
        List<User> userFromSlave = slaveUserMapper.getAllUsers();
        users.addAll(userFromSlave);
        return users;
    }
}

1. 跨数据源事务

@Service
public class UserService {
    @Autowired
    private UserMapper userMapper;

    @Autowired
    private OrderMapper orderMapper;

    @Transactional(rollbackFor = Exception.class)
    public void updateUserInfoAndOrder(Order order, User user) {
        userMapper.updateUserInfo(user);
        orderMapper.updateOrder(order);
        if (1 == 1) {
            throw new RuntimeException("Exception");
        }
    }
}

以上这些就是 SpringBoot 整合 Mybatis 实现多数据源配置与跨数据源事务实例的详细步骤和示例。