jdk8 list新特性demo

public static void main(String[] args) {
        //jdk8 stream对list数据去重，使用filter()过滤列表，list转map
        //去除List中重复的String
        List<String> list = new ArrayList<>();
        list.add("aaa");
        list.add("bbb");
        list.add("bbb");
        List unique = list.stream().distinct().collect(Collectors.toList());
        System.out.println("unique: " + unique);

        List<Person> persons = new ArrayList<>();
        persons.add(new Person("1", "jack", "boy"));
        persons.add(new Person("2", "jack", "boy"));
        persons.add(new Person("3", "tom", "boy"));
        persons.add(new Person("4", "mary", "girl"));

        //根据name去重
        List<Person> name = persons.stream().collect(Collectors.collectingAndThen(
                Collectors.toCollection(() -> new TreeSet<>(Comparator.comparing(Person::getName))),
                ArrayList::new
        ));
        System.out.println("name: " + name);

        //根据name和sex去重
        List<Person> nameSex = persons.stream().collect(Collectors.collectingAndThen(
                Collectors.toCollection(() -> new TreeSet<>(Comparator.comparing(o -> o.getName() + ";" + o.getSex()))),
                ArrayList::new
        ));
        System.out.println("nameSex: " + nameSex);

        //filter()过滤列表
        List<Person> filterList = persons.stream().filter(person -> person.getSex().equals("girl")).collect(Collectors.toList());
        System.out.println("filterList: " + filterList);

        //list转map
        Map<String,Object> toMap = persons.stream().collect(Collectors.toMap(p->p.getId(),p->p.getName()));
        System.out.println("toMap: " + toMap);

    }