I am trying to parse a JSON Array which looks something like this
"data":["data1","data2","data3"]
If I write JSONArray arr = obj1.getJSONArray("data");, this will provide me with the JSON array but since the key name from key-value pair is missing, how will I retrieve "data1", "data2" and "data3"?
JSON arrays allows for non json children. In this case, the children are of String value:
for(int i=0;i<arr.length();i++) {
String value = arr.getString(i);
}
My syntax might be inaccurate
Assuming this is your JSON,
{"data":["data1","data2","data3"]}
Use the following to retrieve the array,
JSONArray arrJson = jsonData.getJSONArray("data");
String[] arr = new String[arrJson.length()];
for(int i = 0; i < arrJson.length(); i++) {
arr[i] = arrJson.getString(i);
}
Related
Hi Below is a simple method which I am using to dynamically generate the JSON request based on Array length from some other API response.
However inside the for loop everything seems to work fine except at the end when JSONArray.add is called, it replaces old jsonObject values inside the array to a new one, and at the end whole array consists of the only same set of JSON objects.
After a lot of debugging can't find the solution, is due to a variable declaration or something. Below is the method I am using
For ref: I am using minidev.JSON
public JSONObject method1(JSONObject sampleJsonObjTemplate, String responseofotherapi) {
JSONArray jsonArray = JsonPath.parse(responseofotherapi).read("$.columns");
JSONArray dataSetColumnArray = new JSONArray();
JSONArray currentJsonColumnArr= JsonPath.parse(dataSetObj).read("$.columns");
JSONObject currentJsonColumnObject= (JSONObject) currentJsonColumnArr.get(0);
LinkedHashMap<String,Object> currentColumn;
for(int columnNumber = 0; columnNumber < jsonArray.size(); columnNumber++){
currentColumn= (LinkedHashMap<String,Object>)jsonArray.get(columnNumber);
String name = currentColumn.get("name").toString();
currentJsonColumnObject.put("name",name);
currentJsonColumnObject.put("alias",name+" Column Alias ");
currentJsonColumnObject.put("description",name+" Column Description ");
dataSetColumnArray.add(columnNumber,currentJsonColumnObject);
currentColumn.clear();
}
JSONObject updatedDataSetReq=JsonPath.parse(dataSetObj).set("$.columns",dataSetColumnArray).json();
return updatedDataSetReq;
}
The problem is with your currentJsonColumnObject object assigning in for loop.
you are using the same object currentJsonColumnObject for all iterations which is referring to currentJsonColumnArr.get(0).
To solve your issue you need to set a different object for currentJsonColumnObject.
JSONArray jsonArray = JsonPath.parse(responseofotherapi).read("$.columns");
JSONArray dataSetColumnArray = new JSONArray();
JSONArray currentJsonColumnArr= JsonPath.parse(dataSetObj).read("$.columns");
//object will be set inside loop
JSONObject currentJsonColumnObject;
LinkedHashMap<String,Object> currentColumn;
for(int columnNumber = 0; columnNumber < jsonArray.size(); columnNumber++){
currentColumn= (LinkedHashMap<String,Object>)jsonArray.get(columnNumber);
// getting object from `currentJsonColumnArr` instead of using the same.
currentJsonColumnObject= (JSONObject) currentJsonColumnArr.get(columnNumber);
String name = currentColumn.get("name").toString();
currentJsonColumnObject.put("name",name);
currentJsonColumnObject.put("alias",name+" Column Alias ");
currentJsonColumnObject.put("description",name+" Column Description ");
dataSetColumnArray.add(columnNumber,currentJsonColumnObject);
currentColumn.clear();
}
I have a JSON object that looks like this
{"layout":[["12","21","31"],["empty","22","32"],["13","23","33"]]}
I am trying to get the array data within with:
JSONObject layoutJson;
JSONArray layoutData = layoutJson.getJSONArray();
However I end up with a single entry in the array of
[["12","21","31"],["empty","22","32"],["13","23","33"]]
How do I get this out of the JSON object in the form of 3 arrays?
JSONObject layoutJson;
JSONArray layoutData = layoutJson.getJSONArray();
for (int i = 0; i < layoutData.length(); i++) {
JSONObject firstArray = (JSONObject)layoutData.getJSONObject(i);
// Do whatever you want with first array
// you can loop through the first array again
}
I am trying to extract the value from a key-value pair in a JSONObect. Here is the structure:
{"key1 ":["dog","cat"],"key2":["house","boat"]}
So, I want to extract the values dog and cat, also values house and boat. I tried the following in Java:
//obj - has this JSON.
Iterator iter = obj.keys();
for (int i=0; i<len; i++){
String key = (String)iter.next();
System.out.println("Key is --> "+key); //This is correctly giving me the keys.
System.out.println("Value is --> "+clientDetails.getJSONArray(key)); //This is not working. I tried lots of other things but to no avail.
}
Could somebody please guide me here.
thanks,
Kay
You should use quick-json parser (https://code.google.com/p/quick-json/)
It can be used like this:
JsonParserFactory factory=JsonParserFactory.getInstance();
JSONParser parser=factory.newJsonParser();
Map jsonMap=parser.parseJson(jsonString);
Taken via : How to parse JSON in Java
This guy has explained it nicely.
I think you are using wrong variable named clientDetails here. you should use same JSON obj here.
The above code is working fine for me with same obj:
String json = "{\"key1 \":[\"dog\",\"cat\"],\"key2\":[\"house\",\"boat\"]}";
JSONObject obj=new JSONObject(json);
Iterator iter = obj.keys();
for (int i=0; i<obj.length(); i++){
String key = (String)iter.next();
System.out.println("Key is --> "+key);
System.out.println("Value is --> "+obj.getJSONArray(key));
}
Thank you for chipping in. I found the answer to my question. Here is how I extracted the value of a JSON which is key value pair, and the value is an array.
Iterator iter = obj.keys();
for (int i=0; i<len; i++){
String key = (String)iter.next();
System.out.println("Key is --> "+key);
String[] arr = (String[])clientDetails.get(key); //Here I am extracting the value which is an array, converting it to String array and then storing it in a variable of type String[]. Now I can loop through this "arr"
for (int m=0; m<arr.length;m++){
arr[]m // Can do whatever I want here!
}
Thank you guys!
-Kay
i have this JSON object:
{"error":null,
"result":[{"id":"1234567890",
"count":1,
"recipients":
["u3848",
"u8958",
"u7477474"
],
"dateCreated":"2012-06-13T09:13:45.989Z"
}]
}
and I'm trying to find a way to correctly parse the recipients array into a String[] object.
is there an easy way to do this?
EDIT:
found this answer that has all the things needed for result: Sending and Parsing JSON Objects
the way to do what I wanted was this:
JSONArray temp = jsonObject.getJSONArray("name");
int length = temp.length();
if (length > 0) {
String [] recipients = new String [length];
for (int i = 0; i < length; i++) {
recipients[i] = temp.getString(i);
}
}
You can try to use xstream with json serializer. Take a look this link
I always suggest my favorite library json-lib to handle JSON stuffs.
You can use JSONArray to convert to Object[], although it's not String[], you can still use it because every Object has toString() method.
String sYourJsonString = "['u3848', 'u8958', 'u7477474']";
Object[] arrayReceipients = JSONArray.toArray (JSONArray.fromObject(sYourJsonString));
System.out.println (arrayReceipients [0]); // u3848
I am building an android app that needs to download and synchronise with an online database, I am sending my query from the app to a php page which returns the relevant rows from a database in JSON format.
can someone please tell me the best way to iterate through a JSON array?
I receive an array of objects:
[{json object},{json object},{json object}]
What is the simplest piece of code I could use to access the JSONObjects in the array?
EDIT: now that I think of it the method I used to iterate the loop was:
for (String row: json){
id = row.getInt("id");
name = row.getString("name");
password = row.getString("password");
}
So I guess I had was somehow able to turn the returned Json into and iterable array. Any Ideas how I could achieve this?
I apologise for my vaguness but I had this working from an example I found on the web and have since been unable to find it.
I think this code is short and clear:
int id;
String name;
JSONArray array = new JSONArray(string_of_json_array);
for (int i = 0; i < array.length(); i++) {
JSONObject row = array.getJSONObject(i);
id = row.getInt("id");
name = row.getString("name");
}
Is that what you were looking for?
I have done it two different ways,
1.) make a Map
HashMap<String, String> applicationSettings = new HashMap<String,String>();
for(int i=0; i<settings.length(); i++){
String value = settings.getJSONObject(i).getString("value");
String name = settings.getJSONObject(i).getString("name");
applicationSettings.put(name, value);
}
2.) make a JSONArray of names
JSONArray names = json.names();
JSONArray values = json.toJSONArray(names);
for(int i=0; i<values.length(); i++){
if (names.getString(i).equals("description")){
setDescription(values.getString(i));
}
else if (names.getString(i).equals("expiryDate")){
String dateString = values.getString(i);
setExpiryDate(stringToDateHelper(dateString));
}
else if (names.getString(i).equals("id")){
setId(values.getLong(i));
}
else if (names.getString(i).equals("offerCode")){
setOfferCode(values.getString(i));
}
else if (names.getString(i).equals("startDate")){
String dateString = values.getString(i);
setStartDate(stringToDateHelper(dateString));
}
else if (names.getString(i).equals("title")){
setTitle(values.getString(i));
}
}
Unfortunately , JSONArray doesn't support foreach statements, like:
for(JSONObject someObj : someJsonArray) {
// do something about someObj
....
....
}
When I tried #vipw's suggestion, I was faced with this exception:
The method getJSONObject(int) is undefined for the type JSONArray
This worked for me instead:
int myJsonArraySize = myJsonArray.size();
for (int i = 0; i < myJsonArraySize; i++) {
JSONObject myJsonObject = (JSONObject) myJsonArray.get(i);
// Do whatever you have to do to myJsonObject...
}
If you're using the JSON.org Java implementation, which is open source, you can just make JSONArray implement the Iterable interface and add the following method to the class:
#Override
public Iterator iterator() {
return this.myArrayList.iterator();
}
This will make all instances of JSONArray iterable, meaning that the for (Object foo : bar) syntax will now work with it (note that foo has to be an Object, because JSONArrays do not have a declared type). All this works because the JSONArray class is backed by a simple ArrayList, which is already iterable. I imagine that other open source implementations would be just as easy to change.
On Arrays, look for:
JSONArray menuitemArray = popupObject.getJSONArray("menuitem");
You are using the same Cast object for every entry.
On each iteration you just changed the same object instead creating a new one.
This code should fix it:
JSONArray jCastArr = jObj.getJSONArray("abridged_cast");
ArrayList<Cast> castList= new ArrayList<Cast>();
for (int i=0; i < jCastArr.length(); i++) {
Cast person = new Cast(); // create a new object here
JSONObject jpersonObj = jCastArr.getJSONObject(i);
person.castId = (String) jpersonObj.getString("id");
person.castFullName = (String) jpersonObj.getString("name");
castList.add(person);
}
details.castList = castList;
While iterating over a JSON array (org.json.JSONArray, built into Android), watch out for null objects; for example, you may get "null" instead of a null string.
A check may look like:
s[i] = array.isNull(i) ? null : array.getString(i);