Lambda表达式中针对List的常用方法

 

• List =>Map

Map map = list1.stream().collect(Collectors.toMap(People::getName, people -> people));

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• List 分组

Map> mapList = list1.stream().collect(Collectors.groupingBy(People::getName));

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• List 排序 – 从低到高

list1.sort((p1, p2) -> p1.getAge() - p2.getAge());

• List 多条件排序 – 先按照年龄，再按照身高

list1.sort(Comparator.comparing(People::getAge).thenComparing(People::getHeight));