java HashSet LinkedHashSet

一、HashSet

1、特点

a、唯一

b、无序

c、无索引

2、方法

与Collection方法相同

3、案例

package com.wt.set;

import java.util.Collections;
import java.util.HashSet;

public class Demon01 {
    public static void main(String[] args) {
        HashSet<Student> set = new HashSet<>();
        Student p1 = new Student("小薪", 6);
        Student p2 = new Student("小葵", 2);
        Student p3 = new Student("美呀", 36);
        Student p4 = new Student("小葵", 2);

        System.out.println("p1 = " + p1.hashCode());
        System.out.println("p2 = " + p2.hashCode());
        System.out.println("p3 = " + p3.hashCode());
        System.out.println("p4 = " + p4.hashCode());

        Collections.addAll(set, p1, p2, p3, p4);
        System.out.println("set = " + set);

    }
}

二、LinkedHashSet

1、特点

a、唯一

b、有序

c、无索引

2、方法

与 Collection相同

3、案例

package com.wt.set;

import java.util.LinkedHashSet;

public class Demon02 {
    public static void main(String[] args) {
        LinkedHashSet<Student> set = new LinkedHashSet<>();

        set.add(new Student("喜洋洋", 9));
        set.add(new Student("懒洋洋", 7));
        set.add(new Student("喜洋洋", 9));
        set.add(new Student("沸羊羊", 10));
        set.add(new Student("慢羊羊", 80));

        System.out.println("set = " + set);
    }
}