Java HashSet 存储学生对象 去重示例：姓名、性别、年龄相同元素不重复

1. 学生类Student的定义：

public class Student {
    private String name;
    private String gender;
    private int age;

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

    public String getName() {
        return name;
    }

    public void setName(String name) {
        this.name = name;
    }

    public String getGender() {
        return gender;
    }

    public void setGender(String gender) {
        this.gender = gender;
    }

    public int getAge() {
        return age;
    }

    public void setAge(int age) {
        this.age = age;
    }

    @Override
    public boolean equals(Object obj) {
        if (obj == null) {
            return false;
        }
        if (obj == this) {
            return true;
        }
        if (obj.getClass() != getClass()) {
            return false;
        }
        Student other = (Student) obj;
        return name.equals(other.name) && gender.equals(other.gender) && age == other.age;
    }

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

2. 测试类及main()方法：

import java.util.HashSet;
import java.util.Set;

public class Test {
    public static void main(String[] args) {
        Student s1 = new Student('张三', '男', 20);
        Student s2 = new Student('李四', '女', 21);
        Student s3 = new Student('张三', '男', 20);

        Set<Student> set = new HashSet<Student>();
        set.add(s1);
        set.add(s2);
        set.add(s3);

        for (Student s : set) {
            System.out.println('姓名：' + s.getName() + '，性别：' + s.getGender() + '，年龄：' + s.getAge());
        }
    }
}