Parse JSON to Java object with dynamics objects in JSON-response

Question

I am trying to parse a JSON-response to a Java object and then I want to save it to a Postgresql.

I have the following json-response:

{
    "success": 1,
    "results": [
        {
            "FI": "120986750",
            "event_id": "5164306",
            "cards": {
                "updated_at": "1660559432",
                "key": "AAA100",
                "sp": {
                    "corners": {
                        "id": "1",
                        "name": "Cards",
                        "odds": [
                            {
                                "id": "101",
                                "odds": "2.200",
                                "header": "Over",
                                "name": "11"
                            },
                            {
                                "id": "102",
                                "odds": "8.500",
                                "header": "Exactly",
                                "name": "11"
                            },
                            {
                                "id": "103",
                                "odds": "1.909",
                                "header": "Under",
                                "name": "11"
                            }
                        ]
                    }
                }
            },
            "corners": {
                "updated_at": "1660559431",
                "key": "AAA200",
                "sp": {
                    "corners": {
                        "id": "2",
                        "name": "Corners",
                        "odds": [
                            {
                                "id": "201",
                                "odds": "2.200",
                                "header": "Over",
                                "name": "10"
                            },
                            {
                                "id": "202",
                                "odds": "8.500",
                                "header": "Exactly",
                                "name": "10"
                            },
                            {
                                "id": "203",
                                "odds": "1.909",
                                "header": "Under",
                                "name": "10"
                            }
                        ]
                    }
                }
            }
        }
    ]
}

I started to create a class like this:

public class PreMatchOdds {

    @JsonProperty("success")
    private Integer success;
    @JsonProperty("results")
    private List<Result> results = null;
    @JsonIgnore
    private Map<String, Object> additionalProperties = new HashMap<String, Object>();
    private final static long serialVersionUID = -8631993296159893856L;

getter and setters..

Then instead of

    @JsonProperty("cards")
    private Cards cards;

and

    @JsonProperty("corners")
    private Corners corners;

I tried with:

@JsonProperty("categories")
@JsonAlias({"cards", "corners"})
private Categories categories;

in the Result class

public class Result implements Serializable {

    @JsonProperty("FI")
    private String fi;
    @JsonProperty("event_id")
    private String eventId;
    
    @JsonProperty("categories")
    @JsonAlias({"cards", "corners"})
    private Categories categories;

    @JsonIgnore
    private Map<String, Object> additionalProperties = new HashMap<String, Object>();
    private final static long serialVersionUID = -683759794150688410L;

How is the proper way to do this or do I have to create a class for each cards and corners object? This is just an example but in my real case I have like 20 of this objects. I would also like to set the object key name to a variable since I want to map it against a field in the database.

I have tried and googled but not found what I am looking for or not really understood. In the end I would like to save it to a table in a database like this:

FI	event_id	category	updated_at	key	market_id	market	odds_id	odds	header	handicap	name
FI value	event_id	value	"cards"	updated_at	AAA100	cards.id	cards.name	odds.id	odds.odds	odds.header	odds.handicap
			"corners"	AAA200	corners.id	corners.name	odds.id	odds.odds	odds.header	odds.handicap	odds.name
Example
120986750	5164306	cards	1660559432	AAA100	1	Cards	101	2.2	Over		11
120986750	5164306	cards	1660559432	AAA100	1	Cards	102	8.5	Exatly		11
120986750	5164306	cards	1660559432	AAA100	1	Cards	103	1.909	Under		11
120986750	5164306	corners	1660559431	AAA200	2	Corners	201	2.2	Over		10
120986750	5164306	corners	1660559431	AAA200	2	Corners	202	8.5	Exatly		10
120986750	5164306	corners	1660559431	AAA200	2	Corners	203	1.909	Under		10

Answer 1

It is complicated to handle dynamic contents by defining many Classes. I suggest to transform the JSON directly using JSON query library. For example, use Josson .

https://github.com/octomix/josson

Deserialization

Josson josson = Josson.fromJsonString(
    "{" +
    "    \"success\": 1," +
    "    \"results\": [" +
    "        {" +
    "            \"FI\": \"120986750\"," +
    "            \"event_id\": \"5164306\"," +
    "            \"cards\": {" +
    "                \"updated_at\": \"1660559432\"," +
    "                \"key\": \"AAA100\"," +
    "                \"sp\": {" +
    "                    \"cards\": {" +
    "                        \"id\": \"1\"," +
    "                        \"name\": \"Cards\"," +
    "                        \"odds\": [" +
    "                            {" +
    "                                \"id\": \"101\"," +
    "                                \"odds\": \"2.200\"," +
    "                                \"header\": \"Over\"," +
    "                                \"name\": \"11\"" +
    "                            }," +
    "                            {" +
    "                                \"id\": \"102\"," +
    "                                \"odds\": \"8.500\"," +
    "                                \"header\": \"Exactly\"," +
    "                                \"name\": \"11\"" +
    "                            }," +
    "                            {" +
    "                                \"id\": \"103\"," +
    "                                \"odds\": \"1.909\"," +
    "                                \"header\": \"Under\"," +
    "                                \"name\": \"11\"" +
    "                            }" +
    "                        ]" +
    "                    }" +
    "                }" +
    "            }," +
    "            \"corners\": {" +
    "                \"updated_at\": \"1660559431\"," +
    "                \"key\": \"AAA200\"," +
    "                \"sp\": {" +
    "                    \"corners\": {" +
    "                        \"id\": \"2\"," +
    "                        \"name\": \"Corners\"," +
    "                        \"odds\": [" +
    "                            {" +
    "                                \"id\": \"201\"," +
    "                                \"odds\": \"2.200\"," +
    "                                \"header\": \"Over\"," +
    "                                \"name\": \"10\"" +
    "                            }," +
    "                            {" +
    "                                \"id\": \"202\"," +
    "                                \"odds\": \"8.500\"," +
    "                                \"header\": \"Exactly\"," +
    "                                \"name\": \"10\"" +
    "                            }," +
    "                            {" +
    "                                \"id\": \"203\"," +
    "                                \"odds\": \"1.909\"," +
    "                                \"header\": \"Under\"," +
    "                                \"name\": \"10\"" +
    "                            }" +
    "                        ]" +
    "                    }" +
    "                }" +
    "            }" +
    "        }" +
    "    ]" +
    "}");

Transformation

JsonNode node = josson.getNode(
    "results.map(" +
    "    FI," +
    "    event_id," +
    "    categories: entries()" +
    "        .map(category: key," +
    "             value.updated_at," +
    "             value.key," +
    "             market_id: value.sp.*.id," +
    "             market: value.sp.*.name," +
    "             value.sp.*.odds)" +
    "        .unwind(odds)" +
    ").unwind(categories)");
System.out.println(node.toPrettyString());

Output

[ {
  "FI" : "120986750",
  "event_id" : "5164306",
  "category" : "cards",
  "updated_at" : "1660559432",
  "key" : "AAA100",
  "market_id" : "1",
  "market" : "Cards",
  "id" : "101",
  "odds" : "2.200",
  "header" : "Over",
  "name" : "11"
}, {
  "FI" : "120986750",
  "event_id" : "5164306",
  "category" : "cards",
  "updated_at" : "1660559432",
  "key" : "AAA100",
  "market_id" : "1",
  "market" : "Cards",
  "id" : "102",
  "odds" : "8.500",
  "header" : "Exactly",
  "name" : "11"
}, {
  "FI" : "120986750",
  "event_id" : "5164306",
  "category" : "cards",
  "updated_at" : "1660559432",
  "key" : "AAA100",
  "market_id" : "1",
  "market" : "Cards",
  "id" : "103",
  "odds" : "1.909",
  "header" : "Under",
  "name" : "11"
}, {
  "FI" : "120986750",
  "event_id" : "5164306",
  "category" : "corners",
  "updated_at" : "1660559431",
  "key" : "AAA200",
  "market_id" : "2",
  "market" : "Corners",
  "id" : "201",
  "odds" : "2.200",
  "header" : "Over",
  "name" : "10"
}, {
  "FI" : "120986750",
  "event_id" : "5164306",
  "category" : "corners",
  "updated_at" : "1660559431",
  "key" : "AAA200",
  "market_id" : "2",
  "market" : "Corners",
  "id" : "202",
  "odds" : "8.500",
  "header" : "Exactly",
  "name" : "10"
}, {
  "FI" : "120986750",
  "event_id" : "5164306",
  "category" : "corners",
  "updated_at" : "1660559431",
  "key" : "AAA200",
  "market_id" : "2",
  "market" : "Corners",
  "id" : "203",
  "odds" : "1.909",
  "header" : "Under",
  "name" : "10"
} ]