HashSet去重原理与使用方法详解

import java.util.*;

public class RemoveDuplicates {
    public static void main(String[] args) {
        List list = Arrays.asList("apple", "banana", "apple", "orange", "banana");
        Set set = new HashSet(list);
        System.out.println(set); // 输出：[banana, orange, apple]（顺序不保证）
    }
}

class Person {
    private String name;
    private int age;

    public Person(String name, int age) {
        this.name = name;
        this.age = age;
    }

    @Override
    public boolean equals(Object o) {
        if (this == o) return true;
        if (!(o instanceof Person)) return false;
        Person person = (Person) o;
        return age == person.age && Objects.equals(name, person.name);
    }

    @Override
    public int hashCode() {
        return Objects.hash(name, age);
    }

    @Override
    public String toString() {
        return "Person{name='" + name + "', age=" + age + '}';
    }
}

// 使用示例
public class Main {
    public static void main(String[] args) {
        List people = Arrays.asList(
            new Person("Alice", 25),
            new Person("Bob", 30),
            new Person("Alice", 25)
        );
        Set uniquePeople = new HashSet(people);
        System.out.println(uniquePeople);
        // 输出：[Person{name='Alice', age=25}, Person{name='Bob', age=30}]
    }
}

List noDuplicates = new ArrayList(new HashSet(originalList));