我如何在 java 中遍历此 JSON

Question

我正在尝试遍历 Java 中的以下 Json 对象代码，我正在使用 google gson。

意图：在我的挥杆菜单中，我将按下标有球队名称的按钮，例如：

巴塞罗那足球俱乐部

然后将在按下的相应球队按钮上显示每个球员的列表。

显示的玩家列表示例：

布拉沃、蒙托亚、皮克、拉基蒂奇等

我很难理解如何使用这个 Json 文件来做这件事，我愿意使用完成工作所需的任何库，甚至重新格式化这个 Json 文件本身。

EXTRA：如果有人还可以解释浏览数据的基础知识，以便将来我可以显示团队中每个球员的所有数据（年龄、国籍...），那也很棒!

{
 "Teams":
  {
   "FC Barcelona":{
    "Bravo":{
     "age" : "32",
     "nationality" : "Chile",
     "club" : "FC Barcelona",
     "position": "Goalkeeper",
     "overall" : "83"
    },
    "Montoya":{
     "age" : "24",
     "nationality" : "Spain",
     "club" : "FC Barcelona",
     "position" : "Defender",
     "overall" : "77"
    },
    "Pique":{
     "age" : "28",
     "nationality" : "Spain",
     "club" : "Barcelona",
     "position" : "Defender",
     "overall" : "84"
    },
    "Rakitic":{
     "age" : "27",
     "nationality" : "Croatia",
     "club" : "Barcelona",
     "position" : "Midfielder",
     "overall" : "83"
    },
    "Busquets":{
     "age" : "27",
     "nationality" : "Spain",
     "club" : "Barcelona",
     "position" : "Midfielder",
     "overall" : "86"
    },
    "Xavi":{
     "age" : "35",
     "nationality" : "Spain",
     "club" : "Barcelona",
     "position" : "Midfielder",
     "overall" : "86"
    },
    "Iniesta":{
     "age" : "31",
     "nationality" : "Spain",
     "club" : "Barcelona",
     "position" : "Midfielder",
     "overall" : ""
    },
    "Pedro":{
     "age" : "28",
     "nationality" : "Spain",
     "club" : "Barcelona",
     "position" : "Forward",
     "overall" : "83"
    }, 
    "Suarez":{
     "age" : "28",
     "nationality" : "Uruguay",
     "club" : "Barcelona",
     "position" : "Forward",
     "overall" : "89"
    },    
    "Messi":{
     "age" : "28",
     "nationality" : "Argentina",
     "club" : "Barcelona",
     "position" : "Forward",
     "overall" : "93"
    },
    "Neymar":{
     "age" : "23",
     "nationality" : "Brazil",
     "club" : "Barcelona",
     "position" : "Forward",
     "overall" : "87"
    }    
   }
  }
}

Answer 1

这可能有助于您理解迭代

public class JsonParseTest {

    private static final String filePath = "E:\testJson.json";

    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);
         // get a String from the JSON object

            String firstName = (String) jsonObject.get("firstname");

            System.out.println("The first name is: " + firstName);


          // get a number from the JSON object

            long id =  (long) jsonObject.get("id");

            System.out.println("The id is: " + id);



            // get an array from the JSON object

          JSONArray lang= (JSONArray) jsonObject.get("languages");



            // take the elements of the json array

            for(int i=0; i<lang.size(); i++){

                System.out.println("The " + i + " element of the array: "+lang.get(i));

            }

            Iterator i = lang.iterator();



            // take each value from the json array separately

            while (i.hasNext()) {

                JSONObject innerObj = (JSONObject) i.next();

                System.out.println("language "+ innerObj.get("lang") +

                        " with level " + innerObj.get("knowledge"));

            }

            // handle a structure into the json object

            JSONObject structure = (JSONObject) jsonObject.get("job");

            System.out.println("Into job structure, name: " + structure.get("name"));



        } catch (FileNotFoundException ex) {

            ex.printStackTrace();

        } catch (IOException ex) {

            ex.printStackTrace();

        } catch (ParseException ex) {

            ex.printStackTrace();

        } catch (NullPointerException ex) {

            ex.printStackTrace();

        }



  }




 }

这是 json 文件

{
    "id": 1,
        "firstname": "Katerina",
    "languages": [
        { "lang":"en" , "knowledge":"proficient" }, 
        { "lang":"fr" , "knowledge":"advanced" }, 
    ]
    "job":{
                "site":"www.javacodegeeks.com",
                "name":"Java Code Geeks",
        }  
}

Answer 2

我创建了一个伪代码检查一下。

    try {
                JSONObject root = new JSONObject("YOUR_JSON");
                JSONObject team = root.getJSONObject("Teams").getJSONObject("FC Barcelona");
                Iterator keys =  team.keys(); 

                //iterate each object
                while (keys.hasNext()){
                    JSONObject obj = team.getJSONObject((String)keys.next());
                    String age = obj.getString("age");
                }


            } catch (JSONException e) {
                e.printStackTrace();
            }

我如何在 java 中遍历此 JSON

How can I iterate through this JSON in java

java

iteration

json