将映射键设置为逗号字符串

/** 
来 自 
NowJava.com - 时  代  Java
**/

//package com.nowjava;


import java.util.Iterator;

import java.util.Map;


import java.util.Set;


public class Main {

    public static String setKeysToCommaString(Set s) {


        StringBuffer sb = new StringBuffer();


        Iterator i = s.iterator();


        while (i.hasNext()) {


            Map.Entry o = (Map.Entry) i.next();/** 时 代 J a v a - N o w J a v a . c o m 提 供 **/


            sb.append((String) o.getKey());


            if (i.hasNext())