Java TreeSet的使用

Java TreeSet的使用

Comparable和Comparator的区别 ：https://www.cnblogs.com/szlbm/p/5504634.html
参考博客:https://www.cnblogs.com/yzssoft/p/7127894.html
使用详解

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

//Comparable和Comparator的区别 https://www.cnblogs.com/szlbm/p/5504634.html
//参考博客:https://www.cnblogs.com/yzssoft/p/7127894.html
public class TreeSetUse {
    static class person implements Comparable{
        public String name;
        public int age;
        public person(String name,int age){
            this.name=name;
            this.age=age;
        }

        @Override
        public int compareTo(person o) {
            //按照年纪从小到大排序，name从小到大排序
            if(o.age==this.age) {
                return this.name.compareTo(o.name);//String类实现了compareTo方法
            }else return this.age-o.age;
        }
        public String toString(){
            return this.name+" "+this.age;
        }
    }
    static class comparator implements Comparator{
        //从大到小排序，与person类的排序方式相反
//        @Override
//        public int compare(person o1, person o2) {
//            return o2.compareTo(o1);
//        }
        @Override
        public int compare(person o1,person o2){
            if(o1.age==o2.age){
                return o2.name.compareTo(o1.name);
            }else return o2.age-o1.age;
        }
    }
    public static void main(String[] args){
        person p1=new person("p1",1);
        person p2=new person("p2",2);
        person p3=new person("p3",3);
        person p4=new person("p4",4);
        person p5=new person("p5",5);
        person p6=new person("p6",6);
        TreeSet tree=new TreeSet<>(new comparator());
        tree.add(p1);
        tree.add(p5);
        tree.add(p4);
        tree.add(p3);
        tree.add(p2);
        tree.add(p6);
        for(person p:tree){
            System.out.println(p.toString());
        }
    }
}