code: public DataNode getDataNode(final String dataSourceName, final String logicTableName) {
          TableRule tableRule = getTableRule(logicTableName);
          for (DataNode each : tableRule.getActualDataNodes()) {
              if (shardingDataSourceNames.getDataSourceNames().contains(each.getDataSourceName()) && each.getDataSourceName().equals(dataSourceName)) {
                  return each;
              }
          }
          throw new ShardingConfigurationException("Cannot find actual data node for data source name: '%s' and logic table name: '%s'", dataSourceName, logicTableName);
      }
docs: Find data node by data source and logic table.
  
  @param dataSourceName data source name
  @param logicTableName logic table name
  @return data node