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/**
 * 主从配置
 *
 * @author wyq
 * @date 2020年07月24日01:24:42
 */
@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);
 }
}

cnblogs.com/wyq178/p/13352707.html