我使用一个名为JSONObject的JSON库(如果需要，我不介意切换)。
我知道如何遍历JSONArrays，但当我从Facebook解析JSON数据时，我没有得到一个数组，只有一个JSONObject，但我需要能够通过它的索引访问一个项目，如JSONObject[0]来获得第一个，我不知道如何做到这一点。
{
"http://http://url.com/": {
"id": "http://http://url.com//"
},
"http://url2.co/": {
"id": "http://url2.com//",
"shares": 16
}
,
"http://url3.com/": {
"id": "http://url3.com//",
"shares": 16
}
}
当前回答
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
}
}
其他回答
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
}
}
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();
}
}
Iterator<JSONObject> iterator = jsonObject.values().iterator();
while (iterator.hasNext()) {
jsonChildObject = iterator.next();
// Do whatever you want with jsonChildObject
String id = (String) jsonChildObject.get("id");
}
我曾经有一个json，有id需要加1，因为他们是0索引，这是打破Mysql自动增量。
因此，对于每个对象，我都写了这段代码-可能对某些人有帮助:
public static void incrementValue(JSONObject obj, List<String> keysToIncrementValue) {
Set<String> keys = obj.keySet();
for (String key : keys) {
Object ob = obj.get(key);
if (keysToIncrementValue.contains(key)) {
obj.put(key, (Integer)obj.get(key) + 1);
}
if (ob instanceof JSONObject) {
incrementValue((JSONObject) ob, keysToIncrementValue);
}
else if (ob instanceof JSONArray) {
JSONArray arr = (JSONArray) ob;
for (int i=0; i < arr.length(); i++) {
Object arrObj = arr.get(0);
if (arrObj instanceof JSONObject) {
incrementValue((JSONObject) arrObj, keysToIncrementValue);
}
}
}
}
}
用法:
JSONObject object = ....
incrementValue(object, Arrays.asList("id", "product_id", "category_id", "customer_id"));
这也可以转换为JSONArray作为父对象
