java Lambda表达式如何按条件动态传入方法引用？-灵析社区
皮皮踢java中如何按条件传入分组 例如有个学生类集合，如何动态传入一个方法引用来分组？ list.stream().collect(Collectors.groupingBy(Student::getSex)); list.stream().collect(Collectors.groupingBy(Student::getAge)); public List test(动态传入){ // ...list list.stream().collect(Collectors.groupingBy(动态传入)); return list }
无心插柳柳成萌public static List groupBy(List list, Function dynamicReference) {
Map> groupedStudents = list.stream()
.collect(Collectors.groupingBy(dynamicReference));
return groupedStudents.values().stream()
.flatMap(Collection::stream)
.collect(Collectors.toList());
}
public static void main(String[] args) {
List students = Arrays.asList(
new Student("Alice", "female", 20),
new Student("Bob", "male", 22),
new Student("Charlie", "male", 23),
new Student("Alice", "female", 21),
new Student("Bob", "male", 22)
);
List groupedBySex = groupBy(students, Student::getSex);
List groupedByAge = groupBy(students, Student::getAge);
System.out.println(Arrays.toString(groupedBySex.toArray()));
System.out.println(Arrays.toString(groupedByAge.toArray()));
}