java基础集合之HashSet练习（带答案）

ps：案例来源于毕向东老师Java基础教程


问题：往hashSet集合中存入自定对象，姓名和年龄相同为同一个人，重复元素。


案例代码；


import java.util.*;
class HashSetTest {
public static void sop(Object obj) {
System.out.println(obj);
}


public static void main(String[] args) {
HashSet hs = new HashSet();


hs.add(new Person("a1", 11));
hs.add(new Person("a2", 12));
hs.add(new Person("a3", 13));
// hs.add(new Person("a2",12));
// hs.add(new Person("a4",14));


// sop("a1:"+hs.contains(new Person("a2",12)));


// hs.remove(new Person("a4",13));


Iterator it = hs.iterator();


while (it.hasNext()) {
Person p = (Person) it.next();
sop(p.getName() + "::" + p.getAge());
}
}
}


class Person {
private String name;
private int age;


Person(String name, int age) {
this.name = name;
this.age = age;
}


public int hashCode() {
System.out.println(this.name + "....hashCode");
return name.hashCode() + age * 37;
}


public boolean equals(Object obj) {


if (!(obj instanceof Person))
return false;


Person p = (Person) obj;
System.out.println(this.name + "...equals.." + p.name);


return this.name.equals(p.name) && this.age == p.age;
}


public String getName() {
return name;
}


public int getAge() {
return age;
}
}