Iterator<JSONObject> iterator = jsonObject.values().iterator();

while (iterator.hasNext()) {
 jsonChildObject = iterator.next();

 // Do whatever you want with jsonChildObject 

  String id = (String) jsonChildObject.get("id");
}

jsonobject现在有一个keySet()方法，它返回一个Set<String>，可以很容易地通过for-each循环。

for(String key : jsonObject.keySet())

这是该问题的另一种有效解决方案:

public void test (){

    Map<String, String> keyValueStore = new HasMap<>();
    Stack<String> keyPath = new Stack();
    JSONObject json = new JSONObject("thisYourJsonObject");
    keyValueStore = getAllXpathAndValueFromJsonObject(json, keyValueStore, keyPath);
    for(Map.Entry<String, String> map : keyValueStore.entrySet()) {
        System.out.println(map.getKey() + ":" + map.getValue());
    }   
}

public Map<String, String> getAllXpathAndValueFromJsonObject(JSONObject json, Map<String, String> keyValueStore, Stack<String> keyPath) {
    Set<String> jsonKeys = json.keySet();
    for (Object keyO : jsonKeys) {
        String key = (String) keyO;
        keyPath.push(key);
        Object object = json.get(key);

        if (object instanceof JSONObject) {
            getAllXpathAndValueFromJsonObject((JSONObject) object, keyValueStore, keyPath);
        }

        if (object instanceof JSONArray) {
            doJsonArray((JSONArray) object, keyPath, keyValueStore, json, key);
        }

        if (object instanceof String || object instanceof Boolean || object.equals(null)) {
            String keyStr = "";

            for (String keySub : keyPath) {
                keyStr += keySub + ".";
            }

            keyStr = keyStr.substring(0, keyStr.length() - 1);

            keyPath.pop();

            keyValueStore.put(keyStr, json.get(key).toString());
        }
    }

    if (keyPath.size() > 0) {
        keyPath.pop();
    }

    return keyValueStore;
}

public void doJsonArray(JSONArray object, Stack<String> keyPath, Map<String, String> keyValueStore, JSONObject json,
        String key) {
    JSONArray arr = (JSONArray) object;
    for (int i = 0; i < arr.length(); i++) {
        keyPath.push(Integer.toString(i));
        Object obj = arr.get(i);
        if (obj instanceof JSONObject) {
            getAllXpathAndValueFromJsonObject((JSONObject) obj, keyValueStore, keyPath);
        }

        if (obj instanceof JSONArray) {
            doJsonArray((JSONArray) obj, keyPath, keyValueStore, json, key);
        }

        if (obj instanceof String || obj instanceof Boolean || obj.equals(null)) {
            String keyStr = "";

            for (String keySub : keyPath) {
                keyStr += keySub + ".";
            }

            keyStr = keyStr.substring(0, keyStr.length() - 1);

            keyPath.pop();

            keyValueStore.put(keyStr , json.get(key).toString());
        }
    }
    if (keyPath.size() > 0) {
        keyPath.pop();
    }
}

我将避免迭代器，因为它们可以在迭代过程中添加/删除对象，也可以为循环使用干净的代码。它将是简单的干净和更少的行。

使用Java 8和Lamda[更新4/2/2019]

import org.json.JSONObject;

public static void printJsonObject(JSONObject jsonObj) {
    jsonObj.keySet().forEach(keyStr ->
    {
        Object keyvalue = jsonObj.get(keyStr);
        System.out.println("key: "+ keyStr + " value: " + keyvalue);

        //for nested objects iteration if required
        //if (keyvalue instanceof JSONObject)
        //    printJsonObject((JSONObject)keyvalue);
    });
}

使用旧方式[更新4/2/2019]

import org.json.JSONObject;

public static void printJsonObject(JSONObject jsonObj) {
    for (String keyStr : jsonObj.keySet()) {
        Object keyvalue = jsonObj.get(keyStr);

        //Print key and value
        System.out.println("key: "+ keyStr + " value: " + keyvalue);

        //for nested objects iteration if required
        //if (keyvalue instanceof JSONObject)
        //    printJsonObject((JSONObject)keyvalue);
    }
}

原来的答案

import org.json.simple.JSONObject;
public static void printJsonObject(JSONObject jsonObj) {
    for (Object key : jsonObj.keySet()) {
        //based on you key types
        String keyStr = (String)key;
        Object keyvalue = jsonObj.get(keyStr);

        //Print key and value
        System.out.println("key: "+ keyStr + " value: " + keyvalue);

        //for nested objects iteration if required
        if (keyvalue instanceof JSONObject)
            printJsonObject((JSONObject)keyvalue);
    }
}

我们使用下面的一组代码遍历JSONObject字段

Iterator iterator = jsonObject.entrySet().iterator();

while (iterator.hasNext())  {
        Entry<String, JsonElement> entry = (Entry<String, JsonElement>) iterator.next();
        processedJsonObject.add(entry.getKey(), entry.getValue());
}

下面的代码对我来说很好。如果可以调音，请帮助我。这甚至可以从嵌套的JSON对象中获得所有的键。

public static void main(String args[]) {
    String s = ""; // Sample JSON to be parsed

    JSONParser parser = new JSONParser();
    JSONObject obj = null;
    try {
        obj = (JSONObject) parser.parse(s);
        @SuppressWarnings("unchecked")
        List<String> parameterKeys = new ArrayList<String>(obj.keySet());
        List<String>  result = null;
        List<String> keys = new ArrayList<>();
        for (String str : parameterKeys) {
            keys.add(str);
            result = this.addNestedKeys(obj, keys, str);
        }
        System.out.println(result.toString());
    } catch (ParseException e) {
        e.printStackTrace();
    }
}
public static List<String> addNestedKeys(JSONObject obj, List<String> keys, String key) {
    if (isNestedJsonAnArray(obj.get(key))) {
        JSONArray array = (JSONArray) obj.get(key);
        for (int i = 0; i < array.length(); i++) {
            try {
                JSONObject arrayObj = (JSONObject) array.get(i);
                List<String> list = new ArrayList<>(arrayObj.keySet());
                for (String s : list) {
                    putNestedKeysToList(keys, key, s);
                    addNestedKeys(arrayObj, keys, s);
                }
            } catch (JSONException e) {
                LOG.error("", e);
            }
        }
    } else if (isNestedJsonAnObject(obj.get(key))) {
        JSONObject arrayObj = (JSONObject) obj.get(key);
        List<String> nestedKeys = new ArrayList<>(arrayObj.keySet());
        for (String s : nestedKeys) {
            putNestedKeysToList(keys, key, s);
            addNestedKeys(arrayObj, keys, s);
        }
    }
    return keys;
}

private static void putNestedKeysToList(List<String> keys, String key, String s) {
    if (!keys.contains(key + Constants.JSON_KEY_SPLITTER + s)) {
        keys.add(key + Constants.JSON_KEY_SPLITTER + s);
    }
}



private static boolean isNestedJsonAnObject(Object object) {
    boolean bool = false;
    if (object instanceof JSONObject) {
        bool = true;
    }
    return bool;
}

private static boolean isNestedJsonAnArray(Object object) {
    boolean bool = false;
    if (object instanceof JSONArray) {
        bool = true;
    }
    return bool;
}