/**

 * Created by hzlizhou on 2017/2/6.

 */

public abstract class MultiDatasourceDao implements IDaoSupport {

 

  private Map<String, SqlSessionTemplate> sqlSessionTemplateMap;

 

  private MultiDataSourceSelector multiDataSourceSelector;

 

  public MultiDatasourceDao(Map<String, SqlSessionTemplate> sqlSessionTemplateMap, MultiDataSourceSelector multiDataSourceSelector) {

    this.sqlSessionTemplateMap = sqlSessionTemplateMap;

    this.multiDataSourceSelector = multiDataSourceSelector;

  }

 

  public Map<String, SqlSessionTemplate> getSqlSessionTemplateMap() {

    return sqlSessionTemplateMap;

  }

 

  public void setSqlSessionTemplateMap(Map<String, SqlSessionTemplate> sqlSessionTemplateMap) {

    this.sqlSessionTemplateMap = sqlSessionTemplateMap;

  }

 

  //子类通过这个方法动态获取SqlSessionTemplate

  protected SqlSessionTemplate getSqlSessionTemplate() {

    String clusterName = multiDataSourceSelector.getName();

    SqlSessionTemplate result = sqlSessionTemplateMap.get(clusterName);

    Assert.notNull(result);

    return result;

  }

}　 

public interface MultiDataSourceSelector {

  String getName();

}

public class DubboContextDataSourceSelector implements MultiDataSourceSelector {

 

  private String defaultName;

 

  public DubboContextDataSourceSelector(String defaultName) {

    this.defaultName = defaultName;

  }

 

  @Override

  public String getName() {

    //DubboContextHolder 是一个保持一个ThreadLocal的Map

    String res = DubboContextHolder.getContext().get(DubboContextConstants.CLUSTER_NAME);

    if (res == null) {

      res = getDefaultName();

    }

    return res;

  }

 

  public String getDefaultName() {

    return defaultName;

  }

} 

@Documented

@Target({METHOD, TYPE})

@Retention(RUNTIME)

public @interface DynamicTransactional {

 

  Propagation propagation() default Propagation.REQUIRED;

 

  Class<? extends Throwable>[] rollbackFor() default {};

} 

private Object invokeWithinTransaction(final ProceedingJoinPoint pjp, final DynamicTransactional dynamicTransaction) {

 

  //创建TransactionTemplate

  final PlatformTransactionManager tran = multiTransactionManagerHolder.getTransactionManager();

  TransactionTemplate transactionTemplate = new TransactionTemplate();

  transactionTemplate.setPropagationBehavior(dynamicTransaction.propagation().value());

  transactionTemplate.setTransactionManager(tran);

 

  //在事务中执行

  return transactionTemplate.execute(new TransactionCallback<Object>() {

    @Override

    public Object doInTransaction(TransactionStatus status) {

      Object result = null;

      try {

        result = pjp.proceed();

      } catch (Throwable throwable) {

        Class<? extends Throwable>[] c = dynamicTransaction.rollbackFor();

        for (Class<? extends Throwable> tmp : c) {

          if (tmp.isAssignableFrom(throwable.getClass())) {

            status.setRollbackOnly();

          }

        }

      }

      return result;

    }

  });

} 

<aop:config>

  <aop:aspect id="multiTransactionManagerAspect" ref="multiTransactionManagerAop">

    <aop:around method="invokeWithinTransaction"

               arg-names="dynamicTransaction"

               pointcut="@annotation(dynamicTransaction)"/>

  </aop:aspect>

</aop:config>