code: public static void clear(boolean rollbackOrCommit) {
          Integer c = Trans.count.get();
          if (c == null)
              return;
          if (c > 0) {
              for (int i = 0; i < c; i++) {
                  try {
                      if (rollbackOrCommit)
                          Trans.rollback();
                      else
                          Trans.commit();
                      Trans.close();
                  }
                  catch (Exception e) {
                  }
              }
          }
          Trans.count.set(null);
          Transaction t = get();
          if (t != null)
              t.close();
          Trans.trans.set(null);
      }
docs: 强制清理事务上下文
  @param rollbackOrCommit 检测到未闭合的事务时回滚还是提交，true为回滚，false为提交。