排序的方法

第一個

import java.util.*;

public class PQ {

    public static void main(String[] args){

        PriorityQueue<String> pq= new PriorityQueue<String>();

        pq.add("carrot");

        pq.add("apple");

        pq.add("banana");

  System.out.println(pq.poll()+";"+pq.peek());

Ans:apple;banana

第二個：

import java.util.*;

public class Ex_TreeSet {

public static void main(String[] args){

HashSet hs = new HashSet();

hs.add("carrot");

hs.add("apple");

hs.add("banana");

TreeSet ts = new TreeSet(hs);

Iterator it = ts.iterator();

while(it.hasNext()){

String data = (String)it.next();

System.out.println(data + ",");

}

}

}

Ans:

apple,

banana,

carrot,