通过 java 解析包含动态字段的 JSON 文件

Question

如何使用包含动态字段的对象解析 JSON 文件。作为此处的示例：这是“项目”，其中包含名称为（“1c68b853-2a07-4409-ad61-8650212f3260”）和正文的对象。而且还不止2件。

{
    "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
            }
        }
    }
}

Answer 1

您可以手动解析 Json。例如，如果您使用 jackson 库 (com.fasterxml.jackson.databind)，您可以

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

那你就可以深挖结构了

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

您还可以枚举个人节点的成员。其他库即 Gson 具有相同的功能

Answer 2

您可以轻松使用Map界面，存储动态部分：

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);
    }
}

您也可以为name、modifiedDate、id创建三个不同的类，但这足以说明主要思想回答。

通过 java 解析包含动态字段的 JSON 文件

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