HashSet和TreeSet的使用与排列顺序的观察

最新推荐文章于 2021-04-14 16:54:59 发布

footprint10

最新推荐文章于 2021-04-14 16:54:59 发布

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本文链接：https://blog.youkuaiyun.com/footprint01/article/details/82221434

博客主要围绕HashSet和TreeSet展开，涉及它们的使用方法，同时对其元素顺序进行观察。这两种集合在信息技术领域的数据处理等方面有重要应用。

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package com.foot.class02;

import java.util.Comparator;
import java.util.HashSet;
import java.util.Set;
import java.util.TreeSet;

public final class HashTreeSet {
    public static void main(String[] args) {
        System.out.println("*******************************************HashSet无序存放******************************************");
        Set<Student> hashSet = new HashSet<Student>();
        hashSet.add(new Student(1, "张三", "S1002", 12));
        hashSet.add(new Student(2, "朱琪", "S1006", 5));
        hashSet.add(new Student(3, "赵盼", "S1021", 32));
        hashSet.add(new Student(4, "秦静", "S2010", 79));
        hashSet.add(new Student(5, "月英", "S3056", 23));
        for (Student student : hashSet) {
            System.out.println("id:" + student.getId() + "--姓名：" + student.getName() + "--学号：" + student.getNum() + "--年龄：" + student.getAge());
        }
        System.out.println("*******************************************TreeSet年龄升序存放******************************************");
        Set<Student> treeSet = new TreeSet<Student>(new MyComparator());
        treeSet.add(new Student(1, "张三", "S1002", 12));
        treeSet.add(new Student(2, "朱琪", "S1006", 5));
        treeSet.add(new Student(3, "赵盼", "S1021", 32));
        treeSet.add(new Student(4, "秦静", "S2010", 79));
        treeSet.add(new Student(5, "月英", "S3056", 23));
        for (Student student : treeSet) {
            System.out.println("id:" + student.getId() + "--姓名：" + student.getName() + "--学号：" + student.getNum() + "--年龄：" + student.getAge());
        }
    }
}

class MyComparator implements Comparator<Student> {
    @Override
    public int compare(Student o1, Student o2) {
    //返回值如果乘以-1，则将进行降序排列
    //这里还可以定义规则按照字母或汉字进行排列
        return o1.getAge() - o2.getAge();
    }
}

package com.foot.class02;

public class Student {
    private int id;
    private String name;
    private String num;
    private int age;

    public Student() {

    }

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

    public int getId() {
        return id;
    }

    public void setId(int id) {
        this.id = id;
    }

    public String getName() {
        return name;
    }

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

    public String getNum() {
        return num;
    }

    public void setNum(String num) {
        this.num = num;
    }

    public int getAge() {
        return age;
    }

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


}