Parsing complex json, with an unknown number of investments

Question

In general, such a trap ... there is a line that comes from a well-known site. the problem is that in different categories it has many different levels of attachments, which it is impossible to catch with simple for and if. In this connection, I ask for help to push on the right path to get an ArrayList (map) with the data of the type name = aaa id = 111 parent = xx, etc. at the output.

{ "id": "204", "title": "Тип объявления", "type": "select", "values": [ { "id": "1074", "title": "Продам", "params": [ { "id": "532", "title": "Вид объекта", "type": "select", "values": [ { "id": "5494", "title": "Гараж", "params": [ { "id": "783", "title": "Тип гаража", "multiple": true, "type": "select", "values": [ { "id": "10991", "title": "Железобетонный" }, { "id": "10993", "title": "Кирпичный" }, { "id": "10995", "title": "Металлический" } ] } ] }, { "id": "5495", "title": "Машиноместо", "params": [ { "id": "781", "title": "Тип машиноместа", "multiple": true, "type": "select", "values": [ { "id": "10983", "title": "Многоуровневый паркинг" }, { "id": "10985", "title": "Подземный паркинг" }, { "id": "10987", "title": "Крытая стоянка" }, { "id": "10989", "title": "Открытая стоянка" } ] } ] } ] }, { "id": "785", "title": "Охрана", "type": "select", "values": [ { "id": "10997", "title": "Да" }, { "id": "10999", "title": "Нет" } ] } ] }, { "id": "1075", "title": "Сдам", "params": [ { "id": "563", "title": "Вид объекта", "type": "select", "values": [ { "id": "5819", "title": "Гараж", "params": [ { "id": "784", "title": "Тип гаража", "multiple": true, "type": "select", "values": [ { "id": "10992", "title": "Железобетонный" }, { "id": "10994", "title": "Кирпичный" }, { "id": "10996", "title": "Металлический" } ] } ] }, { "id": "5820", "title": "Машиноместо", "params": [ { "id": "782", "title": "Тип машиноместа", "multiple": true, "type": "select", "values": [ { "id": "10984", "title": "Многоуровневый паркинг" }, { "id": "10986", "title": "Подземный паркинг" }, { "id": "10988", "title": "Крытая стоянка" }, { "id": "10990", "title": "Открытая стоянка" } ] } ] } ] }, { "id": "786", "title": "Охрана", "type": "select", "values": [ { "id": "10998", "title": "Да" }, { "id": "11000", "title": "Нет" } ] } ] }, { "id": "1073", "title": "Куплю", "params": [ { "id": "756", "title": "Вид объекта", "type": "select", "values": [ { "id": "10897", "title": "Гараж" }, { "id": "10898", "title": "Машиноместо" } ] } ] }, { "id": "1076", "title": "Сниму", "params": [ { "id": "779", "title": "Вид объекта", "type": "select", "values": [ { "id": "10981", "title": "Гараж" }, { "id": "10982", "title": "Машиноместо" } ] } ] } ] }

do you need all the nodes in the json object to add to the list or some specific ones?
the fact is that in different categories there can be up to 10 nested nodes ... here’s how to sort out this business for a start ...

Artem Konovalov Artem Konovalov 13.6k 14 36 · Accepted Answer · 2016-08-22T11:03:17

Connect the json library

  <dependency> <groupId>org.json</groupId> <artifactId>json</artifactId> <version>20160810</version> </dependency>

An approximate recursive traverse of the json объекта will be the following:

 JSONObject jsonObject = new JSONObject(jsonBodyStr); List<Map<String, String>> result = new ArrayList<>(); parser(jsonObject, "0", result); for (Map<String, String> map : result) System.out.println(map.toString()); private static void parser(JSONObject jsonObject, String parentId, List<Map<String, String>> result) { String currentId = parentId; if (jsonObject.has("id") && jsonObject.has("title")) { Map<String, String> object = new HashMap<>(); currentId = jsonObject.getString("id"); object.put("id", currentId); object.put("name", jsonObject.getString("title")); object.put("parent", parentId); result.add(object); } for (String fieldName : jsonObject.keySet()) if (jsonObject.get(fieldName) instanceof JSONArray) { JSONArray array = jsonObject.getJSONArray(fieldName); for (int i = 0; i < array.length(); i++) parser(array.getJSONObject(i), currentId, result); } }

the json library does not work with my json string .. I try to adapt to gson, but it has no analog keyset ...
you call the keySet method on the wrong type of object you want.
Apparently you have a library in which there is also a JSONObject class, check the imports.
ok, there are methods with similar functionality, they can pull out field names, for example, names() , keys() , getNames(Object object) .

Community spirit ♦ one · Answer 2 · 2016-08-23T06:13:42

Adapted the code of Artem Konovalov to use GSON, now everything works! Thank you very much

 private static void parser(JsonObject jsonObject, String parentId, List<Map<String, String>> result){ String currentId = parentId; if (jsonObject.has("id") && jsonObject.has("title")) { Map<String, String> object = new HashMap<>(); currentId = jsonObject.get("id").toString(); object.put("id", currentId); object.put("name", jsonObject.get("title").toString()); object.put("parent", parentId); result.add(object); } for (Map.Entry<String, JsonElement> fieldName : jsonObject.entrySet()) if (jsonObject.get(fieldName.getKey()) instanceof JsonArray) { JsonArray array = jsonObject.getAsJsonArray(fieldName.getKey()); for (int i = 0; i < array.size(); i++) parser(array.get(i).getAsJsonObject(), currentId, result); } }

at the exit we have

 {id="204", name="Тип объявления", parent=0} {id="1074", name="Продам", parent="204"} {id="532", name="Вид объекта", parent="1074"} {id="5494", name="Гараж", parent="532"} {id="783", name="Тип гаража", parent="5494"} {id="10991", name="Железобетонный", parent="783"} {id="10993", name="Кирпичный", parent="783"} {id="10995", name="Металлический", parent="783"} {id="5495", name="Машиноместо", parent="532"} {id="781", name="Тип машиноместа", parent="5495"} {id="10983", name="Многоуровневый паркинг", parent="781"} {id="10985", name="Подземный паркинг", parent="781"} {id="10987", name="Крытая стоянка", parent="781"} {id="10989", name="Открытая стоянка", parent="781"} {id="785", name="Охрана", parent="1074"} {id="10997", name="Да", parent="785"} {id="10999", name="Нет", parent="785"} {id="1075", name="Сдам", parent="204"} {id="563", name="Вид объекта", parent="1075"} {id="5819", name="Гараж", parent="563"} {id="784", name="Тип гаража", parent="5819"} {id="10992", name="Железобетонный", parent="784"} {id="10994", name="Кирпичный", parent="784"} {id="10996", name="Металлический", parent="784"} {id="5820", name="Машиноместо", parent="563"} {id="782", name="Тип машиноместа", parent="5820"} {id="10984", name="Многоуровневый паркинг", parent="782"} {id="10986", name="Подземный паркинг", parent="782"} {id="10988", name="Крытая стоянка", parent="782"} {id="10990", name="Открытая стоянка", parent="782"} {id="786", name="Охрана", parent="1075"} {id="10998", name="Да", parent="786"} {id="11000", name="Нет", parent="786"} {id="1073", name="Куплю", parent="204"} {id="756", name="Вид объекта", parent="1073"} {id="10897", name="Гараж", parent="756"} {id="10898", name="Машиноместо", parent="756"} {id="1076", name="Сниму", parent="204"} {id="779", name="Вид объекта", parent="1076"} {id="10981", name="Гараж", parent="779"} {id="10982", name="Машиноместо", parent="779"}

The problem of non-working code was in Android Studio, under which I ran normal java code.

Parsing complex json, with an unknown number of investments

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