将arraylist连接成一个字符串，并用逗号将它们组合起来。

//package com.nowjava;/**from N o w  J a v a  .   c o m**/

import java.util.ArrayList;


public class Main {

    /**

     * Joins the arraylist into a single string, combining them with commas.

     * @param list

     * @return

     */

    public static String join(ArrayList<String> list) {

        String item = "";


        for (int i = 0; i < list.size(); i++) {

            if (i > 0)

                item += ",";


            item += list.get(i);