如何替换json文件中的值

Question

我有一个 JSON 文件，即test.json。

{
  "Added": {
    "type": "K",
    "newmem": {
      "IDNew": {
        "id": "777709",
        "type": "LOP"
      },
      "birthDate": "2000-12-09"
    },
    "code": "",
    "newest": {
      "curlNew": "",
      "addedForNew": ""
    }
  }
}

我尝试了以下代码：

File file = new File("test.json");
JSONParser parser = new JSONParser();

JSONObject data =  (JSONObject) parser.parse(
   new FileReader(file.getAbsolutePath()
));//path to the JSON file.
System.out.println(data.toString());

JSONObject jObject  = new JSONObject();
jObject.put("id","12345678");
System.out.println(jObject);

结果获取：-

{
  "Added": {
    "type": "K",
    "newmem": {
      "IDNew": {
        "id": "777709",
        "type": "LOP"
      },
      "birthDate": "2000-12-09"
    },
    "code": "",
    "newest": {
      "curlNew": "",
      "addedForNew": ""
    }
  }
}{
"id":"12345678"
}

值 id: "777709" 没有更新到 id:"12345678" 但它终于添加了。请帮助我并告诉我如何替换 id 值。

Answer 1

你可以用简单的 json library(library) 试试这个。我单独打印所有对象以供理解。当您在另外两个对象中声明 Id 对象时，首先您必须获取此对象，然后获取您想要的对象 IDNew。然后将新的 id 值放入 id 字段中。

import java.io.FileNotFoundException;
import java.io.FileReader;
import java.io.IOException;
import java.util.Iterator;

import org.json.simple.JSONArray;
import org.json.simple.JSONObject;
import org.json.simple.parser.JSONParser;
import org.json.simple.parser.ParseException;

public class Main {

    private static final String filePath = "E:\\project-test\\scloud\\test\\src\\main\\resources\\test";

    public static void main(String[] args) {

        try {
            // read the json file
            FileReader reader = new FileReader(filePath);

            JSONParser jsonParser = new JSONParser();
            JSONObject jsonObject = (JSONObject) jsonParser.parse(reader);

            System.out.println(jsonObject);


            JSONObject addedObj = (JSONObject) jsonObject.get("Added");
            System.out.println("Added is: " + addedObj);

            JSONObject newmemObject =(JSONObject) addedObj.get("newmem");
            System.out.println("newmemObject is: " + newmemObject);

            JSONObject idNewObj =(JSONObject) newmemObject.get("IDNew");
            System.out.println("IdNewObj is: " + idNewObj);

            long id =Long.valueOf((String) idNewObj.get("id"));
            System.out.println(id);


            idNewObj.put("id",809809809);

            System.out.println(jsonObject);

        } catch (FileNotFoundException ex) {
            ex.printStackTrace();
        } catch (IOException ex) {
            ex.printStackTrace();
        } catch (ParseException ex) {
            ex.printStackTrace();
        } catch (NullPointerException ex) {
            ex.printStackTrace();
        }

    }

}

或者为简单起见，您可以使用它

    FileReader reader = new FileReader(filePath);
    JSONParser jsonParser = new JSONParser();
    JSONObject jsonObject = (JSONObject) jsonParser.parse(reader);
    System.out.println(jsonObject);

    JSONObject idObj = (
       (JSONObject) (
             (JSONObject) (
                (JSONObject)
                   jsonObject.get("Added")
             ).get("newmem")
       ).get("IDNew")
    );

    idObj.put("id", 98009809);
    System.out.println("After ID value updated : "+jsonObject);

Answer 2

您可以使用 simple-json java lib 更新 JSONObject 中的嵌套元素，如下所示：

JSONObject added = (JSONObject) data.get("Added");
JSONObject newmem = (JSONObject) added.get("newmem");
JSONObject idNew = (JSONObject) newmem.get("IDNew");
idNew.put("id","12345678");
System.out.println(data);

Answer 3

使用不同库的另一种解决方案json-path：

import com.jayway.jsonpath.Configuration;
import com.jayway.jsonpath.DocumentContext;
import com.jayway.jsonpath.JsonPath;
import com.jayway.jsonpath.Option;
import lombok.extern.slf4j.Slf4j;
import org.junit.Test;

import java.io.File;
import java.io.IOException;

import static org.assertj.core.api.Assertions.assertThat;

    @Test
    public void exampleToReplaceSingleElement_jsonTakenFromFile() throws IOException {
        String expectedId = "12345678";
        String expectedJson = "{\n" +
                "  \"Added\": {\n" +
                "    \"type\": \"K\",\n" +
                "    \"newmem\": {\n" +
                "      \"IDNew\": {\n" +
                "        \"id\": \"12345678\",\n" +
                "        \"type\": \"LOP\"\n" +
                "      },\n" +
                "      \"birthDate\": \"2000-12-09\"\n" +
                "    },\n" +
                "    \"code\": \"\",\n" +
                "    \"newest\": {\n" +
                "      \"curlNew\": \"\",\n" +
                "      \"addedForNew\": \"\"\n" +
                "    }\n" +
                "  }\n" +
                "}";

        Configuration configuration = Configuration
                .builder()
                .options(Option.SUPPRESS_EXCEPTIONS)
                .build();
        File json = new File("src/test/resources/test.json");
        System.out.println(json.getAbsolutePath());
        DocumentContext parsed = JsonPath.using(configuration).parse(json);

        parsed.set("$.Added.newmem.IDNew.id", expectedId);
        String actual = parsed.jsonString();

        log.info("After ID value updated: {}", actual);
        assertThat(actual).isEqualToIgnoringWhitespace(expectedJson);
    }

也可以通过获取 test exampleToReplaceSingleElement() 或 test exampleToReplaceSingleElement_jsonTakenFromFile() 访问示例。