从嵌套的 JSON 对象中检索值 [英] Retrieving values from nested JSON Object

问题描述

我有要解析的 JSON 文件.JSON 文件(myfile")的格式如下:

I've got JSON file, which I want to parse. The JSON file ("myfile") has format as follows:

{
    "LanguageLevels": {
        "1": "Początkujący",
        "2": "ŚrednioZaawansowany",
        "3": "Zaawansowany",
        "4": "Ekspert"
    }
}

我想从语言级别检索密钥 2 的值 (ŚrednioZaawansowany).

I want to retrieve value (ŚrednioZaawansowany) of Key 2 from Language Levels.

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 JsonSimpleExample {
public static void main(String[] args) {

JSONParser parser = new JSONParser();

try {

    Object obj = parser.parse(new FileReader("myfile"); 
    JSONObject jsonObject = (JSONObject) obj;
    JSONObject jsonChildObject = (JSONObject)jsonObject.get("LanguageLevels");

接下来要做什么?我如何迭代它?

What to do next? How I can iterate over it?

推荐答案

也许您没有使用最新版本的 JSON for Java 库.

Maybe you're not using the latest version of a JSON for Java Library.

json-simple 好久没更新了，JSON-Java 2个月前就更新了.

json-simple has not been updated for a long time, while JSON-Java was updated 2 month ago.

JSON-Java 可以在 GitHub 上找到，这里是它的 repo 的链接:https://github.com/douglascrockford/JSON-java

JSON-Java can be found on GitHub, here is the link to its repo: https://github.com/douglascrockford/JSON-java

切换库后，您可以参考我下面的示例代码:

After switching the library, you can refer to my sample code down below:

public static void main(String[] args) {
    String JSON = "{"LanguageLevels":{"1":"Pocz\u0105tkuj\u0105cy","2":"\u015arednioZaawansowany","3":"Zaawansowany","4":"Ekspert"}}
";

    JSONObject jsonObject = new JSONObject(JSON);
    JSONObject getSth = jsonObject.getJSONObject("LanguageLevels");
    Object level = getSth.get("2");

    System.out.println(level);
}

并且作为 JSON-Java 开源，您可以阅读代码及其文档，他们将指导您完成.

And as JSON-Java open-sourced, you can read the code and its document, they will guide you through.

希望对您有所帮助.

这篇关于从嵌套的 JSON 对象中检索值的文章就介绍到这了，希望我们推荐的答案对大家有所帮助，也希望大家多多支持IT屋！