element cannot be mapped to a null key
时间:2021-06-15 16:31:41
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Map<Object, Long> a1Map = groupStoreVisiList.stream().filter(map->map.getA1() != null)//这里需要加个判断,该字段不能为null
.collect(Collectors.groupingBy(p -> p.getA1(),Collectors.counting()));
原文:https://www.cnblogs.com/magichu/p/14884331.html
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