7-8 HashSet存入自定义类对象

import java.util.*;
class Student{
	String id;
	String name;
	public Student(String id,String name) {
		this.id=id;
		this.name=name;
	}
	public String toString() {
		return id+":"+name;
	}
}
public class Example {
public static void main(String[]args) {
	HashSet hset=new HashSet();
	hset.add(new Student("1","张三"));
	hset.add(new Student("2","李四"));
	hset.add(new Student("2","李四"));
		System.out.println(hset);
}
}

运行结果：

[1:张三, 2:李四, 2:李四]

注：没有去掉重复元素，因为在Student类中没有重写hashCode()和equals()方法。