使用 JSONObject 打印键值无法按预期工作

Question

我正在尝试打印下面 JSON 中的所有键值，但无论出于何种原因，它只为我打印了第一组值。

如何才能打印出 idValue 字符串中的所有键值？

编辑：我现在收到错误：

意外错误：JSONObject["submenu"] 不是字符串。

代码

import com.google.common.collect.LinkedListMultimap;
import com.google.common.collect.Multimap;
import org.json.JSONArray;
import org.json.JSONObject;

import java.util.Map;

public class testing {
    static Multimap<String, String> allMappedKeyValues = LinkedListMultimap.create();

    public static void main(String[] args) {

        String idValue = "[{\"link\": \"/us_new/en/home\",\"amid\": \"1__home\",\"title\": \"Home\"}, {\"link\": \"/us_new/en/home/diagnosis\",\"amid\": \"2__diagnosis\",\"title\": \"Diagnosis\"}, {\"link\": \"/us_new/en/home/loss\",\"amid\": \"3__loss\",\"title\": \"loss\",\"submenu\": [{\"amid\": \"4__quiz\",\"name\": \"quiz\",\"title\": \"quiz\"},{\"amid\": \"5__questions\",\"name\": \"questions\",\"title\": \"Questions\"}]}]";

        JSONArray array = new JSONArray(idValue);
        for (int i = 0; i < array.length(); i++)
        {
            JSONObject object = array.getJSONObject(i);
            JSONArray keys = object.names();

            for (int j = 0; j < keys.length(); ++j)
            {
                String key = keys.getString(j);
                Object value = object.get(key);

                if (value instanceof JSONArray) {

                    JSONArray array1 = (JSONArray) value;

                    for (int k = 0; k < array1.length(); k++) {
                        JSONObject object1 = array1.getJSONObject(k);

                        JSONArray keys1 = object1.names();

                        String key2 = keys1.getString(k);
                        String value2 = object1.getString(key2);
                        String title2 = object1.getString("title");
//                        System.out.println("-key :" + key2 + "\n-value " + value2 + "\n-title :" + title2);

                        if (key2.contains("amid")) {
                            allMappedKeyValues.put(value2 + "__title", title2);
                        }
                    }
                } else {
                    String key1 = keys.getString(j);
                    String value1 = object.getString(key1);
                    String title1 = object.getString("title");
//                    System.out.println("-key :" + key1 + "\n-value " + value1 + "\n-title :" + title1);

                    if (key.equals("amid")) {
                        allMappedKeyValues.put(value1 + "__title", title1);
                    }
                }
            }
        }

        for (Map.Entry<String, String> entry : allMappedKeyValues.entries()) {
            System.out.println("This is the key-" + entry.getKey() + " value-" + entry.getValue());
        }
    }
}

JSON

[{"link": "/us_new/en/home","amid": "1__home","title": "Home"}, {"link": "/us_new/en/home/diagnosis","amid": "2__diagnosis","title": "Diagnosis"}, {"link": "/us_new/en/home/loss","amid": "3__loss","title": "loss","submenu": [{"amid": "4__quiz","name": "quiz","title": "quiz"},{"amid": "5__questions","name": "questions","title": "Questions"}]}]

输出

  Entered loop :0
-key :link
-value /us_new/en/home
-title :Home
Entered loop :1
-key :amid
-value 1__home
-title :Home
Entered loop :2
-key :title
-value Home
-title :Home

Answer 1

您无需替换 []，您的 JSON 格式正确。您实际上可以直接从字符串创建JSONArray，

String idValue = "[{\"link\":\"/us_new/en/home\",\"amid\":\"1__home\",\"title\":\"Home\"},{\"link\":\"/us_new/en/home/diagnosis\",\"amid\":\"2__diagnosis\",\"title\":\"Diagnosis\"},{\"link\":\"/us_new/en/home/treatment\",\"amid\":\"3__loss\",\"title\":\"loss\"}]";
JSONArray objects = new JSONArray(idValue);
for(int i = 0; i < objects.length(); i++) {
    JSONObject jsonObject = objects.getJSONObject(i);

    Iterator<String> keys = jsonObject.keys();
    while(keys.hasNext()) {
        String key = keys.next();
        System.out.printf("key : %s | value : %s\n", key, jsonObject.get(key));
    }
}

输出：

key : link | value : /us_new/en/home
key : amid | value : 1__home
key : title | value : Home
key : link | value : /us_new/en/home/diagnosis
key : amid | value : 2__diagnosis
key : title | value : Diagnosis
key : link | value : /us_new/en/home/treatment
key : amid | value : 3__loss
key : title | value : loss

Answer 2

您可以使用以下递归函数“parseJsonArray”来解析嵌套的 jsonArrays。

String idValue = "[{\"link\": \"/us_new/en/home\",\"amid\": \"1__home\",\"title\": \"Home\"}, {\"link\": \"/us_new/en/home/diagnosis\",\"amid\": \"2__diagnosis\",\"title\": \"Diagnosis\"}, {\"link\": \"/us_new/en/home/loss\",\"amid\": \"3__loss\",\"title\": \"loss\",\"submenu\": [{\"amid\": \"4__quiz\",\"name\": \"quiz\",\"title\": \"quiz\"},{\"amid\": \"5__questions\",\"name\": \"questions\",\"title\": \"Questions\"}]}]";

parseJsonArray(idValue);

private void parseJsonArray(String jsonString) throws JSONException {
    System.out.println("jsonString: " + jsonString);

    JSONArray objects = new JSONArray(jsonString);
    JSONArray  nestedJsonArray;
    JSONObject  nestedJsonObject;

    for(int i = 0; i < objects.length(); i++) {
        JSONObject jsonObject = objects.getJSONObject(i);
        Iterator<String> keys = jsonObject.keys();

        while(keys.hasNext()) {
            String key = keys.next();                
            Object nestedObject = jsonObject.get(key);
            if (nestedObject instanceof JSONArray) {
                System.out.println("it's an array: " + key);
                nestedJsonArray = (JSONArray)nestedObject;
                parseJsonArray(nestedJsonArray.toString());
            }
            else if (nestedObject instanceof JSONObject) {
                nestedJsonObject = (JSONObject)nestedObject;
                System.out.printf("key : %s | value : %s | title : %s\n", key, nestedJsonObject.getString(key), nestedJsonObject.getString("title"));
            }
            else {
                System.out.printf("key : %s | value : %s | title : %s\n", key, jsonObject.getString(key), jsonObject.getString("title"));
            }
        }
    }

Answer 3

您只读取了第一个 JSON 对象 ({\"link\":\"/us_new/en/home\",\"amid\":\"1__home\",\"title\":\"Home\"})。为了读取所有 3 个对象，首先将 JSON 字符串更改为数组（添加缺少的 [ 和 ]）：

String idValue = "[{\"link\":\"/us_new/en/home\",\"amid\":\"1__home\",\"title\":\"Home\"},{\"link\":\"/us_new/en/home/diagnosis\",\"amid\":\"2__diagnosis\",\"title\":\"Diagnosis\"},{\"link\":\"/us_new/en/home/treatment\",\"amid\":\"3__loss\",\"title\":\"loss\"}]";

然后遍历数组：

JSONArray array = new JSONArray(idValue);
for (int i = 0; i < array.length (); i++) {
    JSONObject object = array.getJSONObject (i);
    JSONArray keys = object.names();
    for (int j = 0; j < keys.length(); ++j) {
        System.out.println("Entered loop :"+j);
        String key = keys.getString(j);
        String value = object.getString(key);
        String title = object.getString("title");
        System.out.println("-key :" + key + "\n-value " + value + "\n-title :" + title);
    }
}

输出：

Entered loop :0
-key :link
-value /us_new/en/home
-title :Home
Entered loop :1
-key :amid
-value 1__home
-title :Home
Entered loop :2
-key :title
-value Home
-title :Home
Entered loop :0
-key :link
-value /us_new/en/home/diagnosis
-title :Diagnosis
Entered loop :1
-key :amid
-value 2__diagnosis
-title :Diagnosis
Entered loop :2
-key :title
-value Diagnosis
-title :Diagnosis
Entered loop :0
-key :link
-value /us_new/en/home/treatment
-title :loss
Entered loop :1
-key :amid
-value 3__loss
-title :loss
Entered loop :2
-key :title
-value loss
-title :loss