一：解析普通json
1：不帶轉(zhuǎn)化字符
格式{"type":"ONLINE_SHIPS","message":{"currentTime":1400077615368,"direction":0,"id":1,"latitude":29.5506,"longitude":106.6466}}

JSONObject jsonObject = new JSONObject(jsonstr).getJSONObject("message");
System.out.println("currentTime:"+jsonObject.get("currentTime"));
System.out.println("direction:"+jsonObject.get("direction"));
System.out.println("latitude:"+jsonObject.get("latitude"));
System.out.println("longitude:"+jsonObject.get("longitude"));

jsonarray

JSONObject jo = ja.getJSONArray("cargoList").getJSONObject(0);

2:帶轉(zhuǎn)義字符的json格式
{"type":"ONLINE_SHIPS","message":"{\"currentTime\":1400077615368,\"direction\":0,\"id\":1,\"latitude\":29.5506,\"longitude\":106.6466}"}
其實(shí)也很簡(jiǎn)單，先把它轉(zhuǎn)化成字符串就可以了

JSONObject jsonObject = new JSONObject(jsonstr);
//先通過(guò)字符串的方式得到,轉(zhuǎn)義字符自然會(huì)被轉(zhuǎn)化掉
String jsonstrtemp = jsonObject.getString("message");
System.out.println("message:"+jsonstrtemp);
jsonObject = new JSONObject(jsonstrtemp);
System.out.println("currentTime:"+jsonObject.get("currentTime"));
System.out.println("direction:"+jsonObject.get("direction"));
System.out.println("latitude:"+jsonObject.get("latitude"));
System.out.println("longitude:"+jsonObject.get("longitude"));

二：遍歷Json對(duì)象

JSONObject ports = ja.getJSONObject("ports");
Iterator<String> keys = ports.keys();
while(keys.hasNext()){
String key=keys.next();
String value = ports.getString(key);
}

三：使用Gjson,json與對(duì)象相互轉(zhuǎn)化
使用Gson輕松將java對(duì)象轉(zhuǎn)化為json格式
String json = gson.toJson(Object);//得到j(luò)son形式的字符串
User user = gson.fromJson(json,User.class);//得到對(duì)象