I have a JSON String and convert it to JsonObject.

I want to get specific data from the JSON object, and every time the JsonObject changes its structure, sometimes it's in an array inside the JSON and sometimes not. example: the first time the JSON arrives like this

{
  "id": "1",
  "Name": "Jack",
  "Value": {
    "data": [
      {"time": "2023", "age": "22"}
    ]
}}

the second time

{ 
  "age": "22",
  "time": "2023",
  "Value": {
    "data": [
      {"Name": "Jack", "id": "1" }
    ]
}}

if I want to get the name in the first JSON

jsonObject.getString("Name")

and for the second one, I would use

jsonObject.getJSONArray("data").getJSONObject(0).getString("Name")

is there a way I can get the value dynamic regardless of where the keys are?

CodePudding user response：

If your API come from an another team or an external provider, the first thing I would suggest to you, is to clearly define a contract. Otherwise, you can use the isNull(String key) method of JSONObject to check if the key exists or not.

An example here:

JSONObject jsonObject = new JSONObject(YOUR_JSON_STRING);
String nameValue;

if(jsonObject.isNull("Name")) {
    nameValue = jsonObject.getJSONObject("Value")
                .getJSONArray("data")
                .getJSONObject(0)
                .getString("Name");
} else {
    nameValue = jsonObject.getString("Name");
}

System.out.println(nameValue);

CodePudding user response：

If the JSON strings are always in a similar fashion then you can try a little parser method as provided below. It returns a Key/Value (String/Object) Map:

public static java.util.Map<String, Object> mapJsonObject(String jsonString) {
    String json = jsonString
            .replaceAll("(?i)[\\[\\]\\{\\}\"]|\"?value\"?:|\"?data\"?:|\n?", "")
            .replaceAll("\\s ", " ");
    String[] keyValueParts = json.split("\\s*,\\s*");
    java.util.Map<String, Object> map = new java.util.HashMap<>();
    for (String str : keyValueParts) {
        String[] pts = str.split("\\s*:\\s*");
        map.put(pts[0].trim(), pts[1]);
    }
    return map;
}

To use:

String jsonString = "{\n"
              "  \"id\": \"1\",\n"
              "  \"Name\": \"Jack\",\n"
              "  \"Value\": {\n"
              "    \"data\": [\n"
              "      {\"time\": \"2023\", \"age\": \"22\"}\n"
              "    ]\n"
              "}}";

java.util.Map<String, Object> map = mapJsonObject(jsonString);
System.out.println(map);

The console window will display:

{id=1, time=2023, age=22 , Name=Jack}