Here you can find the source of joinMapValue(Map
public static String joinMapValue(Map<String, String> map, char connector)
//package com.java2s; import java.util.Map; public class Main { public static String joinMapValue(Map<String, String> map, char connector) { StringBuffer b = new StringBuffer(); for (Map.Entry<String, String> entry : map.entrySet()) { b.append(entry.getKey());//from w w w .j a va 2 s . com b.append('='); if (entry.getValue() != null) { b.append(entry.getValue()); } b.append(connector); } return b.toString(); } }