集合：Hashset的唯一性

Posted 2020-12-27 wtbk

第一部分：

//创建学生类
public class Student {
    //成员变量
    private String name;
    private int age;
    //构造方法
    public Student(){
        super();
    }

    public Student(String name, int age){
        this.name = name;
        this.age = age;
    }
    //成员方法
    public String getName() {
        return name;
    }

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

    public int getAge() {
        return age;
    }

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

    @Override
    public boolean equals(Object o) {
        if (this == o) return true;
        if (!(o instanceof Student)) return false;

        Student student = (Student) o;

        if (getAge() != student.getAge()) return false;
        return getName() != null ? getName().equals(student.getName()) : student.getName() == null;

    }

    @Override
    public int hashCode() {
        int result = getName() != null ? getName().hashCode() : 0;
        result = 31 * result + getAge();
        return result;
    }

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

第二部分：

public class Set {
    public static void main(String[] args){
        //创建集合对象
        HashSet<Student> list = new HashSet<>();
        //创建学生对象
           Student s1 = new Student("苏有朋",38);
           Student s2 = new Student("林志颖",40);
           Student s3 = new Student("蔡依林",35);
           Student s4 = new Student("林志颖",40);
           Student s5 = new Student("苏有朋",38);
           Student s6 = new Student("张无忌",28);
           Student s7 = new Student("周芷若",18);
        //添加到集合
        list.add(s1);
        list.add(s2);
        list.add(s3);
        list.add(s4);
        list.add(s5);
        list.add(s6);
        list.add(s7);
        //遍历新的集合
        for (Student x:list){
            System.out.println(x.getName()+"----"+x.getAge());
        }
    }
}