Java基础视频教程第17天-13-集合(Collections-替换反转)(reverseOrder)(SynList)

import java.util.*;

class StrComparator implements Comparator<String>
{
    public int compare(String s1,String s2)
    {
        /*
        int num = s1.compareTo(s2);
        if(num>0)
            return -1;
        if( num<0)
            return 1;
        return num;
        */

        return s2.compareTo(s1);
    }
}

class StrLenComparator implements Comparator<String>
{
    public int compare(String s1,String s2)
    {
        if(s1.length()>s2.length())
            return 1;
        if(s1.length()<s2.length())
            return -1;
        return s1.compareTo(s2);
    }
}
class CollectionsDemo2
{
    public static void main(String[] args)
    {
        shuffleDemo();
    }
    public static void shuffleDemo()
    {
        List<String> list = new ArrayList<String>();

        list.add("abcd");
        list.add("aaa");
        list.add("zz");
        list.add("kkkkk");
        list.add("qq");
        list.add("z");

        sop(list);
        Collections.shuffle(list);
        sop(list);
    }
    public static void orderDemo()
    {
        TreeSet<String> ts = new TreeSet<String>(Collections.reverseOrder(new StrLenComparator()));

        ts.add("abcde");
        ts.add("aaa");
        ts.add("k");
        ts.add("cc");

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


















    public static void replaceAllDemo()
    {


        List<String> list = new ArrayList<String>();

        list.add("abcd");
        list.add("aaa");
        list.add("zz");
        list.add("kkkkk");

        sop(list);

        Collections.replaceAll(list,"aaa","pp");

        sop(list);
        Collections.reverse(list);

        sop(list);
    }


    /*
    练习。fill方法可以将list集合中所有元素替换成指定元素。
    ，将list集合中部分元素替换成指定元素。

    */
    public static void fillDemo()
    {
        List<String> list = new ArrayList<String>();

        list.add("abcd");
        list.add("aaa");
        list.add("zz");
        list.add("kkkkk");

        sop(list);
        Collections.fill(list,"pp");
        sop(list);

    }
    public static void sop(Object obj)
    {
        System.out.println(obj);
    }
}