SpringBoot MyBatyisPlus 多数据源切换

实现功能为通 aop 控制不同包下面的类采用不同的数据库
- 在 mapper.one 包中的数据库采用 one_db
- 在 mapper.two 包总的数据库采用 two_db

导入相关依赖

<dependency>
    <groupId>com.baomidou</groupId>
    <artifactId>mybatis-plus-boot-starter</artifactId>
    <version>3.2.0</version>
</dependency>
<dependency>
    <groupId>com.alibaba</groupId>
    <artifactId>druid-spring-boot-starter</artifactId>
    <version>1.1.21</version>
</dependency>
<dependency>
    <groupId>org.springframework.boot</groupId>
    <artifactId>spring-boot-starter-aop</artifactId>
</dependency>
<dependency>
    <groupId>org.projectlombok</groupId>
    <artifactId>lombok</artifactId>
    <optional>true</optional>
</dependency>
<dependency>
    <groupId>org.springframework.boot</groupId>
    <artifactId>spring-boot-starter-web</artifactId>
</dependency>

在配置文件中配置数据源

##onedb
spring.datasource.druid.one.driver-class-name=com.mysql.cj.jdbc.Driver
spring.datasource.druid.one.url=jdbc:mysql://localhost:3306/db_one?characterEncoding=utf8&useSSL=false&serverTimezone=GMT%2B8
spring.datasource.druid.one.username=username
spring.datasource.druid.one.password=password

##twodb
spring.datasource.druid.two.driver-class-name=com.mysql.cj.jdbc.Driver
spring.datasource.druid.two.url=jdbc:mysql://localhost:3306/db_two?characterEncoding=utf8&useSSL=false&serverTimezone=GMT%2B8
spring.datasource.druid.two.username=username
spring.datasource.druid.two.password=password

配置 MyBatisPlus 相关

mybatis-plus:
  mapper-locations: classpath:/mapper/**/*Mapper.xml
  typeAliasesPackage: com.sec.datasource.*.domain
  global-config:
    refresh:  true
    db-config:
      id-type: auto
      field-strategy: ignored
      capital-mode: true
      logic-delete-value: 1
      logic-not-delete-value: 0
      db-type: mysql
  configuration:
    map-underscore-to-camel-case: true
    cache-enabled: false
    jdbc-type-for-null: 'null'

在 config 包下配置 MyBatisPlus 数据源

@Configuration
@MapperScan("com.sec.datasource.datasource.mapper")
public class MyBatiesPlusConfiguration {

    @Bean(name = "one")
    @ConfigurationProperties(prefix = "spring.datasource.druid.one" )
    public DataSource one() {
        return DruidDataSourceBuilder.create().build();
    }

    @Bean(name = "two")
    @ConfigurationProperties(prefix = "spring.datasource.druid.two" )
    public DataSource two() {
        return DruidDataSourceBuilder.create().build();
    }

    /**
     * 动态数据源配置
     * @return
     */
    @Bean
    @Primary
    public DataSource multipleDataSource(@Qualifier("one") DataSource onedb, @Qualifier("two") DataSource twodb) {
        MultipleDataSource multipleDataSource = new MultipleDataSource();
        Map< Object, Object > targetDataSources = new HashMap<>();
        targetDataSources.put(DataSourceEnum.ONE_DB.getValue(), onedb);
        targetDataSources.put(DataSourceEnum.TWO_DB.getValue(), twodb);
        //添加数据源
        multipleDataSource.setTargetDataSources(targetDataSources);
        //设置默认数据源
        multipleDataSource.setDefaultTargetDataSource(onedb);
        return multipleDataSource;
    }

    @Bean("sqlSessionFactory")
    public SqlSessionFactory sqlSessionFactory() throws Exception {
        MybatisSqlSessionFactoryBean sqlSessionFactory = new MybatisSqlSessionFactoryBean();
        sqlSessionFactory.setDataSource(multipleDataSource(one(), two()));

        MybatisConfiguration configuration = new MybatisConfiguration();
        configuration.setJdbcTypeForNull(JdbcType.NULL);
        configuration.setMapUnderscoreToCamelCase(true);
        configuration.setCacheEnabled(false);
        sqlSessionFactory.setConfiguration(configuration);
        return sqlSessionFactory.getObject();
    }

}

其他辅助类

public class DataSourceContextHolder {

    private static final ThreadLocal<String> contextHolder = new InheritableThreadLocal<>();

    public static void setDataSource(DataSourceEnum db){
        contextHolder.set(db.getValue());
    }

    public static String getDataSource(){
        return contextHolder.get();
    }

    public static void clear(){
        contextHolder.remove();
    }

}

public class MultipleDataSource extends AbstractRoutingDataSource {

    @Override
    protected Object determineCurrentLookupKey() {
        return DataSourceContextHolder.getDataSource();
    }

}

将已有数据库定义成枚举方便调用

@Getter
public enum DataSourceEnum {

    ONE_DB("one_db"),
    TWO_DB("two_db");

    private String value;

    DataSourceEnum(String value){this.value=value;}

}

编写 aop 逻辑进行数据源切换

@Slf4j
@Aspect
@Order(-1)
@Component
public class DataSourceAspect {

    @Pointcut("execution(* com.sec.datasource.datasource.mapper.onedb.*.*(..))")
    private void onedbAspect() {
    }

    @Pointcut("execution(* com.sec.datasource.datasource.mapper.twodb.*.*(..))")
    private void twodbAspect() {
    }

    @Before("onedbAspect()")
    public void onedb() {
        log.info("select to datasource one");
        DataSourceContextHolder.setDataSource(DataSourceEnum.ONE_DB);
    }

    @Before("twodbAspect()")
    public void twodb() {
        log.info("select to datasource two");
        DataSourceContextHolder.setDataSource(DataSourceEnum.TWO_DB);
    }

    @After("onedbAspect() || twodbAspect()")
    public void doAfter(){
        DataSourceContextHolder.clear();
    }

}