Multiple Data Source Support

As project scale expands, a single data source can no longer meet complex business requirements, leading to the emergence of multiple data sources (dynamic data sources). This document introduces two MyBatis-Plus multi-data source extension plugins: the open-source ecosystem’s dynamic-datasource and the enterprise ecosystem’s mybatis-mate.

dynamic-datasource

dynamic-datasource is an open-source Spring Boot multi-data source starter that provides rich features including data source grouping, sensitive information encryption, independent schema initialization, and more.

Features

• Data Source Grouping: Suitable for various scenarios like read-write separation, one master with multiple slaves, etc.
• Sensitive Information Encryption: Encrypt database configuration information using ENC().
• Independent Initialization: Supports independent schema and database initialization for each database.
• Custom Annotations: Supports custom annotations that need to inherit from DS.
• Simplified Integration: Provides quick integration with connection pools like Druid and HikariCP.
• Component Integration: Supports integration solutions for components like Mybatis-Plus and Quartz.
• Dynamic Data Sources: Supports dynamically adding or removing data sources after project startup.
• Distributed Transactions: Provides distributed transaction solutions based on Seata.

Conventions

• This framework focuses on data source switching and does not restrict specific operations.
• In configuration files, the prefix before the underscore _ in data source names represents the group name.
• Data source switching can use either group names or specific data source names.
• The default data source name is master, which can be modified via spring.datasource.dynamic.primary.
• Method-level annotations take precedence over class-level annotations.

Usage

1. Add Dependency:

• SpringBoot2

<dependency>
  <groupId>com.baomidou</groupId>
  <artifactId>dynamic-datasource-spring-boot-starter</artifactId>
  <version>${version}</version>
</dependency>

• SpringBoot3

<dependency>
 <groupId>com.baomidou</groupId>
 <artifactId>dynamic-datasource-spring-boot3-starter</artifactId>
 <version>${version}</version>
</dependency>

2. Configure Data Sources:

spring:
  datasource:
    dynamic:
      primary: master
      strict: false
      datasource:
        master:
          url: jdbc:mysql://xx.xx.xx.xx:3306/dynamic
          username: root
          password: 123456
          driver-class-name: com.mysql.jdbc.Driver
        slave_1:
          url: jdbc:mysql://xx.xx.xx.xx:3307/dynamic
          username: root
          password: 123456
          driver-class-name: com.mysql.jdbc.Driver
        slave_2:
          url: ENC(xxxxx)
          username: ENC(xxxxx)
          password: ENC(xxxxx)
          driver-class-name: com.mysql.jdbc.Driver

3. Use @DS to Switch Data Sources:

@Service
@DS("slave")
public class UserServiceImpl implements UserService {

  @Autowired
  private JdbcTemplate jdbcTemplate;

  @Override
  @DS("slave_1")
  public List selectByCondition() {
    return jdbcTemplate.queryForList("select * from user where age >10");
  }
}

For more usage tutorials, please refer to the Dynamic-Datasource Official Website

mybatis-mate

mybatis-mate is a paid enterprise component for MyBatis-Plus that includes many useful advanced features, including a multi-data source extension component that provides efficient and simple multi-data source support.

Features

• @Sharding Annotation: Supports switching data sources through annotations.
• Configuration: Supports flexible data source configuration.
• Dynamic Loading/Unloading: Supports dynamically loading and unloading data sources.
• Multi-Data Source Transactions: Supports JTA Atomikos distributed transactions.

Usage

1. Configure Data Sources:

mybatis-mate:
  sharding:
    primary: mysql
    datasource:
      mysql:
        - key: node1
          ...
        - key: node2
          cluster: slave
          ...
      postgres:
        - key: node1
          ...

2. Use @Sharding to Switch Data Sources:

@Mapper
@Sharding("mysql")
public interface UserMapper extends BaseMapper<User> {

    @Sharding("postgres")
    Long selectByUsername(String username);

}

3. Switch to Specific Database Node:

// Switch to mysql slave node2
ShardingKey.change("mysqlnode2");

For more usage examples, please refer to:

• Dynamic Loading/Unloading of Multiple Data Sources: 👉 mybatis-mate-sharding-dynamic

• Multi-Data Source Transactions (jta atomikos): 👉 mybatis-mate-sharding-jta-atomikos

Through the above introduction, we can see that both dynamic-datasource and mybatis-mate provide powerful multi-data source support. Developers can choose the appropriate plugin based on project requirements to achieve flexible data source management.