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
我做了一个小的递归函数，遍历整个json对象并保存键路径及其值。
// My stored keys and values from the json object
HashMap<String,String> myKeyValues = new HashMap<String,String>();
// Used for constructing the path to the key in the json object
Stack<String> key_path = new Stack<String>();
// Recursive function that goes through a json object and stores
// its key and values in the hashmap
private void loadJson(JSONObject json){
Iterator<?> json_keys = json.keys();
while( json_keys.hasNext() ){
String json_key = (String)json_keys.next();
try{
key_path.push(json_key);
loadJson(json.getJSONObject(json_key));
}catch (JSONException e){
// Build the path to the key
String key = "";
for(String sub_key: key_path){
key += sub_key+".";
}
key = key.substring(0,key.length()-1);
System.out.println(key+": "+json.getString(json_key));
key_path.pop();
myKeyValues.put(key, json.getString(json_key));
}
}
if(key_path.size() > 0){
key_path.pop();
}
}
其他回答
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
}
}
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())
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;
}
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
我做了一个小的递归函数，遍历整个json对象并保存键路径及其值。
// My stored keys and values from the json object
HashMap<String,String> myKeyValues = new HashMap<String,String>();
// Used for constructing the path to the key in the json object
Stack<String> key_path = new Stack<String>();
// Recursive function that goes through a json object and stores
// its key and values in the hashmap
private void loadJson(JSONObject json){
Iterator<?> json_keys = json.keys();
while( json_keys.hasNext() ){
String json_key = (String)json_keys.next();
try{
key_path.push(json_key);
loadJson(json.getJSONObject(json_key));
}catch (JSONException e){
// Build the path to the key
String key = "";
for(String sub_key: key_path){
key += sub_key+".";
}
key = key.substring(0,key.length()-1);
System.out.println(key+": "+json.getString(json_key));
key_path.pop();
myKeyValues.put(key, json.getString(json_key));
}
}
if(key_path.size() > 0){
key_path.pop();
}
}
