我有一个对象 Batch(字符串 id、即时日期、长版本)
我有一个批次列表,我想过滤为每个 id 保留一批,其中版本最高,即:
batch1 = Batch(1, date, 5)
batch2 = Batch(2, date, 4)
batch3 = Batch(2, date, 7)
batch4 = Batch(1, date, 2)
batch5 = Batch(1, date, 4)
batch6 = Batch(3, date, 2)
after filtering I need to have
List.of(batch1, batch3, batch6)```
您可以将流与 toMap 一起使用,如下所示:
Collection<Batch> highestVersionBatches = batches.stream()
.collect(Collectors.toMap(
Batch::getId,
batch -> batch,
(e, r) -> e.getVersion() >= r.getVersion() ? e : r // <-- magic goes here
)).values();