Comparable list的使用

import java.util.*;
public class Test{
public static void main(String args[]){
List<Person> list=new ArrayList<Person>();
list.add(new Person("jack",21));
list.add(new Person("rose",18));
list.add(new Person("tom",19));
list.add(new Person("spring",20));
Collections.sort(list);
System.out.println(list);
}
}

class Person implements Comparable{
String name;
int age;
public Person(String name,int age){
this.name=name;
this.age=age;
}
public int compareTo(Object o){
if(o instanceof Person){
Person p=(Person)o;
if(this.age>p.age){
return 1;
}else if(this.age<p.age){
return -1;
}else{
return 0;
}
}else {
return 1;
}
}
public String toString(){
return "name:"+name+",age:"+age;
}
}