I am trying to parse a JSON schema and I need to get all the image links from the JSONArray and store it in a java array. The JSONArray looks like this:
How can I get only the number of strings in the image array for e.g. In this case it should be 4? I know how to get the full length of array but how can I only get the number of strings?
UPDATE:
I am simply parsing it using the standard JSON parser for android. The length of JSONArray can be calculated using:
JSONArray imageArray = hist.getJSONArray("image");
int len = imageArray.length();
len will be equal to 9 in this case.
I'm not sure if there's a better way (there probably is), but here's one option:
According to the Android docs, getJSONObject will throw a JSONException if the element at the specified index is not a JSON object. So, you can try to get the element at each index using getJSONObject. If it throws a JSONException, then you know it's not a JSON object. You can then try and get the element using getString. Here's a crude example:
JSONArray imageArray = hist.getJSONArray("image");
int len = imageArray.length();
ArrayList<String> imageLinks = new ArrayList<String>();
for (int i = 0; i < len; i++) {
boolean isObject = false;
try {
JSONArray obj = imageArray.getJSONObject(i);
// obj is a JSON object
isObject = true;
} catch (JSONException ex) {
// ignore
}
if (!isObject ) {
// Element at index i was not a JSON object, might be a String
try {
String strVal = imageArray.getString(i);
imageLinks.add(strVal);
} catch (JSONException ex) {
// ignore
}
}
}
int numImageLinks = imageLinks.size();
Related
strResponse = {"GetCitiesResult":["1-Vizag","2-Hyderbad","3-Pune","4-Chennai","9-123","11-Rohatash","12-gopi","13-Rohatash","14-Rohatash","10-123"]}
JSONObject json = new JSONObject(strResponse);
// get LL json object
String json_LL = json.getJSONObject("GetCitiesResult").toString();
Now i want to convert the json string to List in andriod
Please make sure your response String is correct format, if it is, then try this:
try {
ArrayList<String> list = new ArrayList<String>();
JSONObject json = new JSONObject(strResponse);
JSONArray array = json.getJSONArray("GetCitiesResult");
for (int i = 0; i < array.length(); i++) {
list.add(array.getString(i));
}
} catch (Exception e) {
e.printStackTrace();
}
Simply using Gson library you can convert json response to pojo class.
Copy the json string to create pojo structure using this link: http://www.jsonschema2pojo.org/
Gson gson = new Gson();
GetCitiesResult citiesResult = gson.fromJson(responseString, GetCitiesResult.class);
It will give the GetCitiesResult object inside that object you get a list of your response like
public List<String> getGetCitiesResult() {
return getCitiesResult;
}
Call only citiesResult.getGetCitiesResult(); it will give a list of cities.
You can also use this library com.squareup.retrofit2:converter-gson:2.1.0
This piece of code did the trick
List<String> list3 = json.getJSONArray("GetCitiesResult").toList()
.stream()
.map(o -> (String) o)
.collect(Collectors.toList());
list3.forEach(System.out::println);
And printed:
1-Vizag
2-Hyderbad
3-Pune
4-Chennai
9-123
11-Rohatash
12-gopi
13-Rohatash
14-Rohatash
10-123
below is code:
private void parse(String response) {
try {
List<String> stringList = new ArrayList<>();
JSONObject jsonObject = new JSONObject(response);
JSONArray jsonArray = jsonObject.getJSONArray("GetCitiesResult");
for (int i=0; i <jsonArray.length(); i++){
stringList.add(jsonArray.getString(i));
}
Log.d ("asd", "--------"+ stringList);
} catch (Exception e) {
e.printStackTrace();
}
}
Hope it will help.
Output is when print list :
--------[1-Vizag, 2-Hyderbad, 3-Pune, 4-Chennai, 9-123, 11-Rohatash, 12-gopi, 13-Rohatash, 14-Rohatash, 10-123]
Ok you must know first something about JSON
Json object is be {// some attribute}
Json Array is be [// some attribute]
Now You have
{"GetCitiesResult":["1-Vizag","2-Hyderbad",
"3-Pune","4-Chennai","9-123","11-Rohatash",
"12-gopi","13-Rohatash","14-Rohatash","10-123"]}
That`s Means you have JSON array is GetCitiesResult
which have array of String
Now Try this
JSONObject obj = new JSONObject(data);
JSONArray loadeddata = new JSONArray(obj.getString("GetCitiesResult"));
for (int i = 0; i <DoctorData.length(); i++) {// what to do here}
where data is your String
I am trying to parse a JsonArray and get its values but I am gettign error when I use
jitem.getString("firstitem");
or
jitem.getJSONObject("firstitem");
or
jitem.get("firstitem");
Following is the code snippet.
JSONArray arr_items = new JSONArray(str);
if(arr_items!=null && arr_items.size()>0){
for(int i=0;i<arr_items.size();i++){
JSONObject jitem = arr_items.getJSONObject(i);//works fine till here
jitem.getString("firstitem"); //throws exception here
}
This is the JSONArray that I am parsing
[{"firstitem":"dgfd","secondtitem":"dfgfdgfdg","thirditem":"fdgfdgdf#sjhasjkdsha.com","fourthitem":"jkksdjklsfjskj"}]
what I am doing wrong? How to get these values by using keys?
Update:Note This array and its parameters are not null at all. They all have valid values.
First check arr_items is not empty.
Then, try surrounding your snippet with try/catch :
try {
your snippet
} catch (JSONException e) {
e.printStackTrace();
}
Check below
String json ="{'array':" + "[{'firstitem':'dgfd','secondtitem':'dfgfdgfdg','thirditem':'fdgfdgdf#sjhasjkdsha.com','fourthitem':'jkksdjklsfjskj'}]"+ "}";
JSONObject myjson = new JSONObject(json);
JSONArray the_json_array = myjson.getJSONArray("array");
int size = the_json_array.length();
// ArrayList<JSONObject> arrays = new ArrayList<JSONObject>();
for (int i = 0; i < size; i++) {
JSONObject another_json_object = the_json_array.getJSONObject(i);
// arrays.add(another_json_object);
System.out.println(another_json_object.get("firstitem"));
}
it require some array name so appended array name to it , if you want without it you have to add GSON.
I'm learning how to work with JSON's in java and I'm having a problem using getString for one of my keys. My code is here:
public static void getJSON(String matchID){
String s = "";
String test = "{\"employees\":[{\"firstName\":\"John\", \"lastName\":\"Doe\"}]}";
try {
JSONObject hi = new JSONObject(test);
JSONArray stuff = hi.getJSONArray("employees");
String[] items = new String[stuff.length()];
items[0] = stuff.getString("firstName");
} catch (JSONException e) {
e.printStackTrace();
}
}
The "getString" is underlined in red, and the "The method getString(int) in the type JSONArray is not applicable for the arguments (String)" I was following an answer to another question word for word almost, and this happens, any advice? Thanks!
EDIT:
I need to get the specifics by name ie. "firstName" because I will be working with thousands of JSONs that each have hundreds of lines.
You need to get the JSOnObject first from the JSONArray(stuff) before you can call getString().
if you want to get the first element in the jsonarray and get its string this is how you would do it
JsonObject obj = stuff.getJsonObject(0);
String name = obj.getString("firstname");
So I figured out my problem, I didn't realize I had an JSONObject first, my apologies. Fixed like this:
JSONObject hi = new JSONObject(test);
JSONArray stuff = hi.getJSONArray("employees");
JSONObject name = stuff.getJSONObject(0);
String[] items = new String[hi.length()];
items[0]=name.getString("firstName");
System.out.println(items[0]);
you can try the simplest way to Parse in JSON
JSONParser parser=new JSONParser();
String s = "{\"employees\":[{\"firstName\":\"John\", \"lastName\":\"Doe\"}]}";
try{
Object obj = parser.parse(s);
JSONArray array = (JSONArray)obj;
System.out.println(array.get(1));
}catch(ParseException pe){
}
I have a web service that performs a database query, converts the result set to a JSON String and returns the strung to the client. This is the code for the converter (I got it from http://biercoff.com/nice-and-simple-converter-of-java-resultset-into-jsonarray-or-xml/):
public static String convertToJSON(ResultSet resultSet)
throws Exception {
JSONArray jsonArray = new JSONArray();
while (resultSet.next()) {
int total_rows = resultSet.getMetaData().getColumnCount();
JSONObject obj = new JSONObject();
for (int i = 0; i < total_rows; i++) {
obj.put(resultSet.getMetaData().getColumnLabel(i + 1)
.toLowerCase(), resultSet.getObject(i + 1));
}
jsonArray.add(obj);
}
return jsonArray.toJSONString();
}
In the client application when I print the returned string it is in the following format:
[{"Column1":0.333333,"Column2":"FirmA"},{"Column1":0.666667,"Column2":"FirmB"}]
so far all is good. The problem I am having is converting the returned string into a JSON array. I tried this:
JSONArray arr = new JSONArray(JSON_STRING);
but got the following error message: constructor JSONArray in class JSONArray cannot be applied to given types. I tried to first convert in into a JSON object like so:
JSONObject obj = new JSONObject(JSON_STRING);
but got the following error: incompatible types: String cannot be converted to Map. What am I doing wrong? Thanks.
Apparently the problem was with the json library that I was using. Once I used the
import org.json.JSONArray;
it all worked out well. I was able to convert the returned string to an array using
JSONArray arr = new JSONArray(JSON_STRING);
and to iterate through the values I used the code provided in this answer: Accessing members of items in a JSONArray with Java which I reproduce here for simplicity:
for (int i = 0; i < arr.length(); ++i) {
JSONObject rec = arr.getJSONObject(i);
int id = rec.getInt("id");
String loc = rec.getString("loc");
// ...
}
well you need to do it by this way for example
String jsonText = "[0,{\"1\":{\"2\":{\"3\":{\"4\":[5,{\"6\":7}]}}}}]";
try {
JSONArray array = new JSONArray(jsonText);
System.out.println(array);
System.out.println(array.length());
} catch (Exception e) {
// TODO: handle exception
e.printStackTrace();
}
}
Check the correct library used. The mess is that org.json.simple is often suggested by IDE as default for JSONObject and JSONArray.
You can find a link to latest jar for org.json library above.
I have created a java server which gets HTTP GET request url as
/Star/getDetails?sentMsg=data.requestorName:ABC,data.companyName:EFG,portfolios:
[{name:,placeholder:Portfolio 1,positions:[{ticker:T1234,weight:29.85},
{ticker:T2345,weight:70.15}],active:false}],analyticsDate:20140630}
I have to parse sentMsg parameter such as I am able to read each variable individually. For eg, i should be able to read data.requestorName, companyName. I am not able to find a way to do it.
request.getParameter("sentMsg") always return String.
Tried parsing it through json-simple
JSONParser jp = new JSONParser();
try {
Object obj = jp.parse(sentMsg);
JSONArray ja = (JSONArray)obj;
} catch (ParseException e) {
e.printStackTrace();
}
But this gives parse exception. I have limitation to use json-simple jar only. Any suggestion on how to do it?
Get the paramter sentMsg from HttpRequest object store it into a string. Split from comma i.e. "," and the last second token would be the json string. You can now parse it using Json simple lib and extract values from it.
Provided you have valid JSON like:
private static String jsonString = "[{name : \"stackOverFlow\"}]";
Convert it to JSONArray like:
JSONArray jsonArray = new JSONArray(jsonString );
Then you can get value out of JSONArray by looping through it:
for (int i = 0; i < jsonArray.length(); i++) { //Iterating over mediaArray
JSONObject media = jsonArray.getJSONObject(i);
String nameFromJSON = media.getString("name");
System.out.println("Name = " + nameFromJSON);
}
Output will be:
//Name = stackOverFlow