基于 SpringBoot 实现 MySQL 读写分离的问题

/**
 * 主从配置
 *
 * @author wyq
 */
@Configuration
@MapperScan(basePackages = "com.wyq.mysqlreadwriteseparate.mapper", sqlSessionTemplateRef = "sqlTemplate")
public class DataSourceConfig {

 /**
  * 主库
  */
 @Bean
 @ConfigurationProperties(prefix = "spring.datasource.master")
 public DataSource master() {
  return DruidDataSourceBuilder.create().build();
 }

 /**
  * 从库
  */
 @Bean
 @ConfigurationProperties(prefix = "spring.datasource.slave")
 public DataSource slaver() {
  return DruidDataSourceBuilder.create().build();
 }


 /**
  * 实例化数据源路由
  */
 @Bean
 public DataSourceRouter dynamicDB(@Qualifier("master") DataSource masterDataSource,
          @Autowired(required = false) @Qualifier("slaver") DataSource slaveDataSource) {
  DataSourceRouter dynamicDataSource = new DataSourceRouter();
  Map<Object, Object> targetDataSources = new HashMap<>();
  targetDataSources.put(DataSourceEnum.MASTER.getDataSourceName(), masterDataSource);
  if (slaveDataSource != null) {
   targetDataSources.put(DataSourceEnum.SLAVE.getDataSourceName(), slaveDataSource);
  }
  dynamicDataSource.setTargetDataSources(targetDataSources);
  dynamicDataSource.setDefaultTargetDataSource(masterDataSource);
  return dynamicDataSource;
 }


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


 /**
  * 创建sqlTemplate
  * @param sqlSessionFactory
  * @return
  */
 @Bean
 public SqlSessionTemplate sqlTemplate(@Qualifier("sessionFactory") SqlSessionFactory sqlSessionFactory) {
  return new SqlSessionTemplate(sqlSessionFactory);
 }


 /**
  * 事务配置
  *
  * @param dynamicDataSource
  * @return
  */
 @Bean(name = "dataSourceTx")
 public DataSourceTransactionManager dataSourceTransactionManager(@Qualifier("dynamicDB") DataSource dynamicDataSource) {
  DataSourceTransactionManager dataSourceTransactionManager = new DataSourceTransactionManager();
  dataSourceTransactionManager.setDataSource(dynamicDataSource);
  return dataSourceTransactionManager;
 }
}

public class DataSourceRouter extends AbstractRoutingDataSource {

 /**
  * 最终的determineCurrentLookupKey返回的是从DataSourceContextHolder中拿到的,因此在动态切换数据源的时候注解
  * 应该给DataSourceContextHolder设值
  *
  * @return
  */
 @Override
 protected Object determineCurrentLookupKey() {
  return DataSourceContextHolder.get();

 }
}

/**
 * 利用ThreadLocal封装的保存数据源上线的上下文context
 */
public class DataSourceContextHolder {

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

 /**
  * 赋值
  *
  * @param datasourceType
  */
 public static void set(String datasourceType) {
  context.set(datasourceType);
 }

 /**
  * 获取值
  * @return
  */
 public static String get() {
  return context.get();
 }

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

@Retention(RetentionPolicy.RUNTIME)
@Target(ElementType.METHOD)
@Documented
public @interface DataSourceSwitcher {
 /**
  * 默认数据源
  * @return
  */
 DataSourceEnum value() default DataSourceEnum.MASTER;
 /**
  * 清除
  * @return
  */
 boolean clear() default true;

}

@Slf4j
@Aspect
@Order(value = 1)
@Component
public class DataSourceContextAop {

 @Around("@annotation(com.wyq.mysqlreadwriteseparate.annotation.DataSourceSwitcher)")
 public Object setDynamicDataSource(ProceedingJoinPoint pjp) throws Throwable {
  boolean clear = false;
  try {
   Method method = this.getMethod(pjp);
   DataSourceSwitcher dataSourceSwitcher = method.getAnnotation(DataSourceSwitcher.class);
   clear = dataSourceSwitcher.clear();
   DataSourceContextHolder.set(dataSourceSwitcher.value().getDataSourceName());
   log.info("数据源切换至：{}", dataSourceSwitcher.value().getDataSourceName());
   return pjp.proceed();
  } finally {
   if (clear) {
    DataSourceContextHolder.clear();
   }

  }
 }

 private Method getMethod(JoinPoint pjp) {
  MethodSignature signature = (MethodSignature) pjp.getSignature();
  return signature.getMethod();
 }

}

@Service
public class OrderService {

 @Resource
 private OrderMapper orderMapper;


 /**
  * 读操作
  *
  * @param orderId
  * @return
  */
 @DataSourceSwitcher(DataSourceEnum.SLAVE)
 public List<Order> getOrder(String orderId) {
  return orderMapper.listOrders(orderId);

 }

 /**
  * 写操作
  *
  * @param orderId
  * @return
  */
 @DataSourceSwitcher(DataSourceEnum.MASTER)
 public List<Order> insertOrder(Long orderId) {
  Order order = new Order();
  order.setOrderId(orderId);
  return orderMapper.saveOrder(order);
 }
}