Parse JSON file with dynamic fields by java-CodePudding

How to parse JSON file with the object, which contains dynamic fields. As an example here: Here is "items", which has objects with name("1c68b853-2a07-4409-ad61-8650212f3260") and body. And it's more then 2 items.

{
    "id": "3c49a7aa-77e0-43cf-956c-a1ff970d7db2",
    "code": "citizenship_country",
    "name": "Гражданство",
    "items": {
        "1c68b853-2a07-4409-ad61-8650212f3260": {
            "name": {
                "id": "1c68b853-2a07-4409-ad61-8650212f3260",
                "value": "ДЖЕРСИ",
                "translation": "ДЖЕРСИ"
            },
            "modifiedDate": {
                "id": "1c68b853-2a07-4409-ad61-8650212f3260",
                "value": "мая 28, 2015",
                "translation": null
            },
            "id": {
                "id": "1c68b853-2a07-4409-ad61-8650212f3260",
                "value": "237",
                "translation": null
            }
        },
        "dfd37aec-4ae7-4d8b-8e92-3a25fab57dd7": {
            "name": {
                "id": "dfd37aec-4ae7-4d8b-8e92-3a25fab57dd7",
                "value": "РОССИЯ",
                "translation": "РОССИЯ"
            },
            "modifiedDate": {
                "id": "dfd37aec-4ae7-4d8b-8e92-3a25fab57dd7",
                "value": "мая 28, 2015",
                "translation": null
            },
            "id": {
                "id": "dfd37aec-4ae7-4d8b-8e92-3a25fab57dd7",
                "value": "185",
                "translation": null
            }
        }
    }
}

CodePudding user response：

You may parse manually th e Json. If you use jackson library (com.fasterxml.jackson.databind) for example you could

var objectMapper = new ObjectMapper();
JsonNode jsonRoot = objectMapper.readTree(jsonStr);

then you can dig into the structure

jsonRoot.path("items").path("1c68b853-2a07-4409-ad61-8650212f3260").asText()

you can also enumerate the members of an individuals node. Other libraries i.e. Gson have the same functionalities

CodePudding user response：

You can easily use the Map interface, to store the dynamic parts:

Root.java:

package com.example.trial.dto;

import java.util.HashMap;
import java.util.Map;
import java.util.UUID;

public class Root {
    public String id;
    public String code;
    public String name;
    public Map<UUID, Map<String, Item>> items = new HashMap<>();
}

Item.java:

package com.example.trial.dto;

import java.util.UUID;

public class Item {
    public UUID id;
    public String value;
    public String translation;
}

MappingTest.java:

package com.example.trial.services;

import com.example.trial.dto.Root;
import com.fasterxml.jackson.databind.ObjectMapper;
import org.junit.jupiter.api.Test;

import java.io.IOException;

public class MappingTest {

    ObjectMapper objectMapper = new ObjectMapper();

    @Test
    public void convert() throws IOException {
        Root root = objectMapper.readValue("{\n"  
            "    \"id\": \"3c49a7aa-77e0-43cf-956c-a1ff970d7db2\",\n"  
            "    \"code\": \"citizenship_country\",\n"  
            "    \"name\": \"Гражданство\",\n"  
            "    \"items\": {\n"  
            "        \"1c68b853-2a07-4409-ad61-8650212f3260\": {\n"  
            "            \"name\": {\n"  
            "                \"id\": \"1c68b853-2a07-4409-ad61-8650212f3260\",\n"  
            "                \"value\": \"ДЖЕРСИ\",\n"  
            "                \"translation\": \"ДЖЕРСИ\"\n"  
            "            },\n"  
            "            \"modifiedDate\": {\n"  
            "                \"id\": \"1c68b853-2a07-4409-ad61-8650212f3260\",\n"  
            "                \"value\": \"мая 28, 2015\",\n"  
            "                \"translation\": null\n"  
            "            },\n"  
            "            \"id\": {\n"  
            "                \"id\": \"1c68b853-2a07-4409-ad61-8650212f3260\",\n"  
            "                \"value\": \"237\",\n"  
            "                \"translation\": null\n"  
            "            }\n"  
            "        },\n"  
            "        \"dfd37aec-4ae7-4d8b-8e92-3a25fab57dd7\": {\n"  
            "            \"name\": {\n"  
            "                \"id\": \"dfd37aec-4ae7-4d8b-8e92-3a25fab57dd7\",\n"  
            "                \"value\": \"РОССИЯ\",\n"  
            "                \"translation\": \"РОССИЯ\"\n"  
            "            },\n"  
            "            \"modifiedDate\": {\n"  
            "                \"id\": \"dfd37aec-4ae7-4d8b-8e92-3a25fab57dd7\",\n"  
            "                \"value\": \"мая 28, 2015\",\n"  
            "                \"translation\": null\n"  
            "            },\n"  
            "            \"id\": {\n"  
            "                \"id\": \"dfd37aec-4ae7-4d8b-8e92-3a25fab57dd7\",\n"  
            "                \"value\": \"185\",\n"  
            "                \"translation\": null\n"  
            "            }\n"  
            "        }\n"  
            "    }\n"  
            "}", Root.class);
        objectMapper.writeValue(System.out, root);
    }
}

You can also, as well, create three different classes for name, modifiedDate, id, but this is enough to show the main idea of the answer.