Question

我正在为java做一个json解析器。我收到json作为字符串，然后我尝试获取所有键值

这是我的Json字符串

 { "Message":{"field": [ {"bit":2,"name":"AAA"}, {"bit":3,"name":"BBB"}]}}

这是我的解析器：

                JSONObject jObject = new JSONObject(result); //result contains the json                 
                JSONArray info = jObject.getJSONArray("field");
                for (int i = 0 ; i < info.length(); i++) {
                    JSONObject obj = info.getJSONObject(i);
                    Iterator<String> keys = obj.keys();
                    while (keys.hasNext()) { //I use key - value cause the json can change
                        String key =  keys.next();
                        System.out.println("Key: " + key + "\tValue: " + obj.get(key));
                    }
                }

但每次我运行代码我都会得到：

Error parsing json org.json.JSONException: JSONObject["field"] not found.

我认为这个领域是JsonArray ......我错了吗？

感谢您的时间

Answer 1

您的某个级别太深，希望从field获得jObject。你需要这样做：

JSONObject jObject = new JSONObject(result);
JSONObject jMsg = jObject.getJSONObject("Message");               
JSONArray info = jMsg.getJSONArray("field");

Answer 2

您需要从JSONArray field

获取JSONObjct Message

String result = "{ \"Message\":{\"field\": [ {\"bit\":2,\"name\":\"AAA\"}, {\"bit\":3,\"name\":\"BBB\"}]}}";
JSONObject jObject = new JSONObject(result).getJSONObject("Message"); //result contains the json
JSONArray info = jObject.getJSONArray("field");
for (int i = 0 ; i < info.length(); i++) {
    JSONObject obj = info.getJSONObject(i);
    Iterator<String> keys = obj.keys();
    while (keys.hasNext()) { //I use key - value cause the json can change
        String key =  keys.next();
        System.out.println("Key: " + key + "\tValue: " + obj.get(key));
    }
}

输出：

Key: name   Value: AAA
Key: bit    Value: 2
Key: name   Value: BBB
Key: bit    Value: 3

Answer 3

试试这个：

        String result = "{ \"Message\":{\"field\": [ {\"bit\":2,\"name\":\"AAA\"}, {\"bit\":3,\"name\":\"BBB\"}]}}";

    JSONObject jObject = new JSONObject(result); //result contains the json
    JSONArray info = jObject.getJSONObject("Message").getJSONArray("field");
    for (int i = 0 ; i < info.length(); i++) {
        JSONObject obj = info.getJSONObject(i);
        Iterator<String> keys = obj.keys();
        while (keys.hasNext()) { //I use key - value cause the json can change
            String key =  keys.next();
            System.out.println("Key: " + key + "\tValue: " + obj.get(key));
        }
    }

解析JsonObject时出错

3 个答案: