day15-07-集合框架(泛型使用)

import java.util.*;

class GenericDemo2 
{
    public static void main(String[] args) 
    {
        TreeSet<String> ts = new TreeSet<String>(new StrLenComparator());
        ts.add("abcd");
        ts.add("cd");
        ts.add("cda");
        ts.add("z");
        ts.add("hahaha");

        Iterator<String> it = ts.iterator();
        while(it.hasNext())
        {
            
            String s = it.next();
            System.out.println(s);
        }
    }
}

class LenComparator implements Comparator<String>
{
    public int compare(String o1,String o2)
    {
        //o1,与o2对象调换就可以按大到小进行排序。
        int num  = new Integer(o1.length()).compareTo(new Integer(o2.length()));
        if(num == 0)
        return o1.compareTo(o2);
        return num;

    }
        
}