麻烦老师帮忙看看，用的集合不对么？

package com.imooc.lx8;

import java.util.ArrayList;

import java.util.HashSet;

import java.util.Iterator;

import java.util.List;

import java.util.Set;

import javax.print.attribute.HashAttributeSet;

public class StudentTest {

public static void main(String[] args) {

//定义三个Student类的对象及一个HashSet类的对象

Student one = new Student(3,"William",65);

Student to = new Student(1,"Tom",87);

Student su = new Student(2,"Lucy",95);

//将Student类的对象添加到集合中

ArrayList li = new ArrayList();

li.add(one);

li.add(to);

li.add(su);

//使用迭代器显示Student类的对象中的内容

Iterator it = li.iterator();

while(it.hasNext()) {

System.out.println(it.next());

}

}

}

package com.imooc.lx8;

public class Student {

private int stuld;

private String name;

private float score;

public Student(int stuld, String name, float score) {

super();

this.stuld = stuld;

this.name = name;

this.score = score;

}

public int getStuld() {

return stuld;

}

public void setStuld(int stuld) {

this.stuld = stuld;

}

public String getName() {

return name;

}

public void setName(String name) {

this.name = name;

}

public float getScore() {

return score;

}

public void setScore(float score) {

this.score = score;

}

@Override

public String toString() {

return "[学号：" + stuld + ", 姓名：" + name + ", 成绩：" + score + "]";

}

@Override

public int hashCode() {

final int prime = 31;

int result = 1;

result = prime * result + ((name == null) ? 0 : name.hashCode());

result = prime * result + Float.floatToIntBits(score);

result = prime * result + stuld;

return result;

}

@Override

public boolean equals(Object obj) {

if (this == obj)

return true;

if (obj == null)

return false;

if (getClass() != obj.getClass())

return false;

Student other = (Student) obj;

if (name == null) {

if (other.name != null)

return false;

} else if (!name.equals(other.name))

return false;

if (Float.floatToIntBits(score) != Float.floatToIntBits(other.score))

return false;

if (stuld != other.stuld)

return false;

return true;

}

}