code: public static void setRouteInfo(String scName, String tbName, Object sdValue) {
          scName = DDRStringUtils.toLowerCase(scName);
          tbName = DDRStringUtils.toLowerCase(tbName);
          if (scName == null) {
              throw new IllegalArgumentException("'scName' can't be empty");
          }
          if (tbName == null) {
              throw new IllegalArgumentException("'tbName' can't be empty");
          }
          if (sdValue == null) {
              sdValue = NULL_OBJECT;
          }
  
          /**
           * 添加两条查询索引
           * schema_name.table_name <-> routeInfo
           * table_name <-> routeInfo
           */
          Map<String, Object> exactRouteContext = getCurContext().getExactRouteContext();
          exactRouteContext.put(buildQueryKey(scName, tbName), sdValue);
          Map<String, Map<String, Object>> ambiguousRouteContext = getCurContext().getAmbiguousRouteContext();
          Map<String, Object> scMap = ambiguousRouteContext.get(tbName);
          if (scMap == null) {
              scMap = new HashMap<>();
              ambiguousRouteContext.put(tbName, scMap);
          }
          scMap.put(scName, sdValue);
      }
docs: 设置路由信息
  相同路由,采用覆盖原则