本文介绍了java stream Collectors.groupingBy()多个字段的处理方法,对大家解决问题具有一定的参考价值,需要的朋友们下面随着小编来一起学习吧!
问题描述
Stream<Map.Entry<String, Long>> duplicates = notificationServiceOrderItemDto.getService()
.getServiceCharacteristics()
.stream()
.collect(
Collectors.groupingBy(
ServiceCharacteristicDto::getName, Collectors.counting()
)
)
.entrySet()
.stream()
.filter(e -> e.getValue() > 1);
Optional<String> dupName = duplicates.map(Map.Entry::getKey).findFirst();
工作完美.但是我很想找到不仅包含名称,而且包含名称+值+键的重复项
works perfect. But I wold like to find duplicates not just with name but also name + value + key
我正在寻找Collectors.groupingBy()
I am looking Collectors.groupingBy()
http://www.technicalkeeda.com/java -8-tutorials/java-8-stream-grouping
但我找不到正确的解决方案
but I can not find correct solution
推荐答案
代替
.collect(Collectors.groupingBy(ServiceCharacteristicDto::getName, Collectors.counting()))
你可以写
.collect(Collectors.groupingBy(s->s.getName()+'-'+s.getValue()+'-'+s.getKey(), Collectors.counting()))
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