java中获取json的所有key方法

String json="{'name':'angui','age':'23','like':'吃水果'}";
JSONObject j = JSON.parseObject(json);
j.remove("age");
System.out.println(json.toString());
System.out.println(j.toJSONString());

//将json转换为key=value&key=value&...的形式
StringBuilder sb = new StringBuilder();
String sbString="";
try {
	org.json.JSONObject jsonObject = new org.json.JSONObject(json);
	Iterator iterator = jsonObject.keys();
	while(iterator.hasNext()){
String key = (String) iterator.next();
	    	sb.append("&"+key);
	    	sb.append("="+jsonObject.getString(key));
	}
	sb.append("&key");
	sbString = sb.substring(1);
} catch (JSONException e) {
	e.printStackTrace();
}
System.out.println(sbString);