在 Java 中，list 根据所选择的

List<ChPersonSetMealCheckItem> chPersonSetMealCheckItems = chSetMealService.selectchPersonSetMealCheckItems(checkItem);

 List<ChPersonSetMealCheckItem> newList = new ArrayList<>();
 List<ChPersonSetMealCheckItem> oldList = new ArrayList<>();

 //要拆分出来的明细id数组
String tkxmid = chsTaocanRefund.getTkxmid();
if (tkxmid != null && !tkxmid.isEmpty()) {
                    String[] arr = tkxmid.split(",");
// 使用 Map 存储 chPersonSetMealCheckItems，通过 id 快速查找
                    Map<String, ChPersonSetMealCheckItem> checkItemMap = chPersonSetMealCheckItems.stream()
                            .collect(Collectors.toMap(ChPersonSetMealCheckItem::getId, item -> item));

                    for (String s : arr) {
                        if (checkItemMap.containsKey(s)) {
                            newList.add(checkItemMap.get(s));
                        }
                    }

                    oldList = chPersonSetMealCheckItems.stream()
                            .filter(item -> !newList.contains(item))
                            .collect(Collectors.toList());
}