Java代码优化：使用流式API高效处理数据

return tableSource.stream() .filter(Objects::nonNull) .map(this::convertScores) .flatMap(Collection::stream) .flatMap(scoreItem -> TreeBuilderUtil.postorderErgodic(scoreItem).stream()) .map(scoreItem -> createScoreRecord(scoreItem, activityId)) .collect(Collectors.toList());