Serialize map to POST data in Java

gistfile1.java

StringBuffer paramStr = new StringBuffer();
for(String key : params.keySet()) {
    paramStr.append(URLEncoder.encode(key));
    paramStr.append("=");
    paramStr.append(URLEncoder.encode(params.get(key)));
    paramStr.append("&");
}
String postData = paramStr.toString();