我正在使用它来获取最新项目.我怎样才能使它成为空安全并使用空日期最后(最旧)进行排序.createDt 是一个 joda LocalDate 对象.
I'm using this to get the newest item. How can I get this to be null safe and sort with null dates last (oldest). createDt is a joda LocalDate object.
Optional<Item> latestItem = items.stream()
.sorted((e1, e2) -> e2.getCreateDt().compareTo(e1.getCreateDt()))
.findFirst();
如果是 Item
可能为 null,请使用 @rgettman 的解决方案.
If it's the Item
s that may be null, use @rgettman's solution.
如果 LocalDate
可能为 null,请使用:
If it's the LocalDate
s that may be null, use this:
items.stream()
.sorted(Comparator.comparing(Item::getCreateDt, Comparator.nullsLast(Comparator.reverseOrder())));
在任何一种情况下,请注意 sorted().findFirst()
可能效率低下,因为大多数标准实现首先对整个流进行排序.您应该使用 Stream.min 代替.
In either case, note that sorted().findFirst()
is likely to be inefficient as most standard implementations sort the entire stream first. You should use Stream.min instead.