简介

基于spring的AbstractRoutingDataSource接口实现的多数据源路由功能，实现不同数据源之间切换

Git地址

https://gitee.com/wqrzsy/lp-demo/tree/master/lp-datasource-router

项目分析

多数据源配置

spring:
  datasource:
    d1:
      platform: mysql
      jdbc-url: jdbc:mysql://localhost:13306/test1?serverTimezone=GMT&useSSL=false
      username: root
      password: 123456
      driver-class-name: com.mysql.cj.jdbc.Driver
    d2:
      platform: mysql
      #      HikariDataSource
      jdbc-url: jdbc:mysql://localhost:13306/test2?serverTimezone=GMT&useSSL=false
      username: root
      password: 123456
      driver-class-name: com.mysql.cj.jdbc.Driver

配置类DataSourceConfiguration
通过@ConfigurationProperties注解实现不同属性注入DataSource，通过 @Primary注解标识DynamicRouterDataSource类，那其他地方拿DataSource时拿到就是代理过的DynamicRouterDataSource类

    @Bean(value = FIRST_DATASOURCE_KEY)
    @Qualifier(FIRST_DATASOURCE_KEY)
    // ConfigurationProperties 指定属性前缀，忽略那些不能绑定到 @ConfigurationProperties 类字段的属性
    @ConfigurationProperties(prefix = "spring.datasource.d1")
    public DataSource masterDataSource() {
        return DataSourceBuilder.create().type(dataSourceType).build();
    }

    @Bean(value = SECOND_DATASOURCE_KEY)
    @Qualifier(SECOND_DATASOURCE_KEY)
    // ConfigurationProperties 指定属性前缀，忽略那些不能绑定到 @ConfigurationProperties 类字段的属性
    @ConfigurationProperties(prefix = "spring.datasource.d2")
    public DataSource slaveDataSource() {
        return DataSourceBuilder.create().type(dataSourceType).build();
    }

    @Primary
    @Bean(name = "routingDataSource")
    public AbstractRoutingDataSource routingDataSource(
        @Qualifier(FIRST_DATASOURCE_KEY) DataSource d1,
        @Qualifier(SECOND_DATASOURCE_KEY) DataSource d2
    ) {
        DynamicRouterDataSource proxy = new DynamicRouterDataSource();
        Map<Object, Object> targetDataSources = new HashMap<>(2);
        targetDataSources.put("masterDataSource", d1);
        targetDataSources.put("slaveDataSource", d2);
        proxy.setDefaultTargetDataSource(d1);
        proxy.setTargetDataSources(targetDataSources);
        DataSourceRouterContext.setDefaultDataSource("masterDataSource");
        return proxy;
    }

准备路由注解

/**
 * 数据库路由注解
 */
@Target(ElementType.METHOD)
@Retention(RetentionPolicy.RUNTIME)
@Documented
@Transactional(propagation = Propagation.REQUIRES_NEW)
public @interface DataSourceRouter {

    String value();

}

路由AOP，这里@Order(-1)是关键，要优先@Transactional切换，在事务之前就切换好数据库

/**
 * 数据库路由AOP
 */
@Aspect
@Component
@Order(-1)
public class DataSourceRouterAOP {

    private static final Logger LOGGER = LoggerFactory.getLogger(DataSourceRouterAOP.class);

    /**
     * 此处的切点是注解的方式，也可以用包名的方式达到相同的效果
     * '@Pointcut("execution(* com.wwj.springboot.service.impl.*.*(..))")'
     */
    @Pointcut("@annotation(DataSourceRouter)")
    public void delayInvoke() {

    }


    /**
     * 环绕增强，相当于MethodInterceptor
     */
    @Around("delayInvoke()")
    public Object doAround(ProceedingJoinPoint joinPoint) throws Throwable {
        MethodSignature signature = (MethodSignature) joinPoint.getSignature();
        Method method = signature.getMethod();
        // 获取DataSourceRouter 注解获取数据源名字
        DataSourceRouter dataSourceRouter = method.getAnnotation(DataSourceRouter.class);
        // 通过DataSourceRouterContext指定当前数据源
        DataSourceRouterContext.setDataSource(dataSourceRouter.value());
        try {
            // 调用方法
            return joinPoint.proceed();
        } finally {
            // 清空环境
            DataSourceRouterContext.clear();
        }
    }

}

4.调用实例

/**
 * 测试路由服务
 */
@Service
public class TestRouterService {

    @Autowired
    private TestEntityDAO testEntityDAO;

    @DataSourceRouter(value = "masterDataSource")
    public void testD1() {
        TestEntity entity = TestEntity.of(System.currentTimeMillis(), "123", 1);
        testEntityDAO.save(entity);
    }

    @DataSourceRouter(value = "slaveDataSource")
    public void testD2() {
        TestEntity entity = TestEntity.of(System.currentTimeMillis(), "123", 1);
        testEntityDAO.save(entity);
    }

}