java8 List＜Object＞去掉重复对象的几种方法

public List<String> removeStringListDupli(List<String> stringList) {

    Set<String> set = new LinkedHashSet<>();

    set.addAll(stringList);

    stringList.clear();

    stringList.addAll(set);

    return stringList;

}

List<String> unique = list.stream().distinct().collect(Collectors.toList());

public class Person {

    private Long id;

    private String name;

    public Person(Long id, String name) {

        this .id = id;

        this .name = name;

    }

    public Long getId() {

        return id;

    }

    public void setId(Long id) {

        this .id = id;

    }

    public String getName() {

        return name;

    }

    public void setName(String name) {

        this .name = name;

    }

    @Override

    public String toString() {

        return "Person{" +

                "id=" + id +

                ", name='" + name + '\ '' +

                '}' ;

    }

}

  @Override

    public boolean equals(Object o) {

        if ( this == o) return true ;

        if (o == null || getClass() != o.getClass()) return false ;

        Person person = (Person) o;

        if (!id.equals(person.id)) return false ;

        return name.equals(person.name);

    }

    @Override

    public int hashCode() {

        int result = id.hashCode();

        result = 31 * result + name.hashCode();

        return result;

    }

  Person p1 = new Person(1l, "jack" );

        Person p2 = new Person(3l, "jack chou" );

        Person p3 = new Person(2l, "tom" );

        Person p4 = new Person(4l, "hanson" );

        Person p5 = new Person(5l, "胶布虫" );

        List<Person> persons = Arrays.asList(p1, p2, p3, p4, p5, p5, p1, p2, p2);

        List<Person> personList = new ArrayList<>();

        // 去重

        persons.stream().forEach(

                p -> {

                    if (!personList.contains(p)) {

                        personList.add(p);

                    }

                }

        );

        System.out.println(personList);

   public static List<Person> removeDupliById(List<Person> persons) {

        Set<Person> personSet = new TreeSet<>((o1, o2) -> o1.getId()测试数据pareTo(o2.getId()));

        personSet.addAll(persons);

        return new ArrayList<>(personSet);

    }

import static java.util.Comparator测试数据paringLong;

import static java.util.stream.Collectors.collectingAndThen;

import static java.util.stream.Collectors.toCollection;

// 根据id去重

      List<Person> unique = persons.stream().collect(

                collectingAndThen(

                        toCollection(() -> new TreeSet<>(comparingLong(Person::getId))), ArrayList:: new )

        );

   public static <T> Predicate<T> distinctByKey(Function<? super T, Object> keyExtractor) {

        Map<Object, Boolean> map = new ConcurrentHashMap<>();

        return t -> map.putIfAbsent(keyExtractor.apply(t), Boolean.TRUE) == null ;

    }

// remove duplicate

        persons.stream().filter(distinctByKey(p -> p.getId())).forEach(p -> System.out.println(p));