/** Concatenate params for URL string */ String concatParams(Properties props) { if (props == null) { return null; } java.util.List list = new ArrayList(); for (Iterator iter = props.keySet().iterator(); iter.hasNext(); ) { String key = (String) iter.next(); String val = props.getProperty(key); if (!StringUtil.isNullString(val)) { list.add(key + "=" + urlEncode(val)); } } return StringUtil.separatedString(list, "&"); }