Set<String> keys = json.keys();
for (String key : keys) {
if("@".equals(key)) {
Json value = json.get(key);
if(value.isString()) {
element.setText(value.str());
} else {
Set<String> ks = value.keys();
for (String k : ks) {
Element child = element.addElement(k);
fromJson(value.get(k), child);