JavaSet集合及其子类HashSet与LinkedHashSet详解

public class HashSetDemo {
    public static void main(String[] args) {
        //创建 Set集合
        HashSet<String>  set = new HashSet<String>();

        //添加元素
        set.add(new String("cba"));
        set.add("abc");
        set.add("bac");
        set.add("cba");
        //遍历
        for (String name : set) {
            System.out.println(name);
        }
    }
}

public class Student {
    private String name;
    private int age;
    public Student() {
    }
    public Student(String name, int age) {
        this.name = name;
        this.age = age;
    }
    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 == null || getClass() != o.getClass())
            return false;
        Student student = (Student) o;
        return age == student.age &&
               Objects.equals(name, student.name);
    }
    @Override
    public int hashCode() {
        return Objects.hash(name, age);
    }
}

public class HashSetDemo2 {
    public static void main(String[] args) {
        //创建集合对象   该集合中存储 Student类型对象
        HashSet<Student> stuSet = new HashSet<Student>();
        //存储 
        Student stu = new Student("张三", 43);
        stuSet.add(stu);
        stuSet.add(new Student("李四", 66));
        stuSet.add(new Student("张三", 43));
        stuSet.add(new Student("王五", 23));
        stuSet.add(stu);

        for (Student stu2 : stuSet) {
            System.out.println(stu2);
        }
    }
}

public class LinkedHashSetDemo {
	public static void main(String[] args) {
		Set<String> set = new LinkedHashSet<String>();
		set.add("bbb");
		set.add("aaa");
		set.add("abc");
		set.add("bbc");
        Iterator<String> it = set.iterator();
		while (it.hasNext()) {
			System.out.println(it.next());
		}
	}
}