我知道IdentityHashMap，但我需要使用类似的东西（用作）。我将使用一个来收听带有“提取器”（JavaFX）的可观察列表："IdentitySet"equalso1 == o2

 List<Person> deleteList = new ArrayList<>();
 List<Person> addList = new ArrayList<>();

 ObservableList<Person> list = FXCollections.observableArrayList(Person.extractor());
    list.add(new Person("a",1));
    list.add(new Person("b",2));
    list.add(new Person("c",3));

    list.addListener((ListChangeListener<Person>) observable -> {
        if(observable.next()) {
            if (observable.wasAdded()) {
                addList.addAll(observable.getAddedSubList());
            }
            if (observable.wasUpdated()) {
                deleteList.add(list.get(observable.getFrom()));
            }
            if (observable.wasRemoved()) {
                deleteList.addAll(observable.getRemoved());
            }
        }
    });

人员类：

public class Person {
private final StringProperty s;
private final DoubleProperty d;

//Getters and Setters
// ...

@Override
public int hashCode() {
    int result = s != null ? s.getValue().hashCode() : 0;
    result = 21 * result + (d != null ? Double.hashCode(d.getValue()) : 0);
    return result;
}

@Override
public boolean equals(Object o) {
    if (this == o) return true;
    if (o == null || getClass() != o.getClass()) return false;

    Person person = (Person) o;
    if (!s.getValue().equals(person.s.getValue())) return false;
    return d.getValue().equals(person.d.getValue());
}


/**
 *Extractor to observe changes in "Property" fields.
 * @return extractor
 */
public static Callback<Person, Observable[]> extractor() {
    return (Person p) -> new Observable[]{p.sProperty(), p.dProperty()};
}

我需要覆盖并解决我的其他问题。equalshashCode

Person p = new Person("a",1);
Set<Object> persons = new HashSet<>();
persons.add(p);
p.setD(999);
persons.add(p);
System.out.println(persons.size());  // size = 2;

persons.remove(p);
System.out.println(persons.size());  // size = 1;