TreeSet集合

package Gather;

import java.util.Comparator;
import java.util.Set;
import java.util.TreeSet;

public class Test2 {
public static void main(String[] args) {
Set set = new TreeSet();
// set.add(4);
// set.add(5);
// set.add(3);
// System.out.println(set); //自然排序 TreeSet
// for(Integer i : set){
// System.out.println(i);
// }
Person p1 = new Person(18,“root”);
Person p2 = new Person(20,“admin”);
Person p3 = new Person(19,“tom”);
//声明集合的泛型为Person对象
Set set1 = new TreeSet( new Person());

    set1.add(p1);
    set1.add(p2);
    set1.add(p3);
    //取Person 对象并赋值给p 使用p在取值
    for (Person  p : set1){
        System.out.println(p.age+" "+ p.name);
    }
}

}
class Person implements Comparator{
int age;
String name ;
public Person () {

}
public Person (int age , String name){
    this.age=age;
    this.name =name ;
}
//把 Person对象存到TreeSet中并且按年龄排序
@Override
public int compare(Person o1, Person o2) { //年龄正序排序
    if (o1.age > o2.age ){
        return 1;
    }else if (o1.age < o2.age){
        return -1;
    }else {
        return 0;
    }

}

}