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());
}

也许这个会有帮助:

JSONObject jsonObject = new JSONObject(contents.trim());
Iterator<String> keys = jsonObject.keys();

while(keys.hasNext()) {
    String key = keys.next();
    if (jsonObject.get(key) instanceof JSONObject) {
          // do something with jsonObject here      
    }
}

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);
    }
}

我让我的小方法记录JsonObject字段，并获得一些刺。看看它是否有用。

object JsonParser {

val TAG = "JsonParser"
 /**
 * parse json object
 * @param objJson
 * @return  Map<String, String>
 * @throws JSONException
 */
@Throws(JSONException::class)
fun parseJson(objJson: Any?): Map<String, String> {
    val map = HashMap<String, String>()

    // If obj is a json array
    if (objJson is JSONArray) {
        for (i in 0 until objJson.length()) {
            parseJson(objJson[i])
        }
    } else if (objJson is JSONObject) {
        val it: Iterator<*> = objJson.keys()
        while (it.hasNext()) {
            val key = it.next().toString()
            // If you get an array
            when (val jobject = objJson[key]) {
                is JSONArray -> {
                    Log.e(TAG, " JSONArray: $jobject")
                    parseJson(jobject)
                }
                is JSONObject -> {
                    Log.e(TAG, " JSONObject: $jobject")
                    parseJson(jobject)
                }
                else -> {
                    Log.e(TAG, " adding to map: $key $jobject")
                    map[key] = jobject.toString()
                }
            }
        }
    }
    return map
}
}

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

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

 // Do whatever you want with jsonChildObject 

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

不敢相信在这个答案中没有更简单和安全的解决方案，而不是使用迭代器…

JSONObject names()方法返回JSONObject键的JSONArray，所以你可以简单地在循环中遍历它:

JSONObject object = new JSONObject ();
JSONArray keys = object.names ();

for (int i = 0; i < keys.length (); i++) {
   
   String key = keys.getString (i); // Here's your key
   String value = object.getString (key); // Here's your value
   
}