I have JSON data to parse. The structure is not fixed, and sometimes it comes as a single string and other times as an array.
Currently, we are using the GSON library for parsing JSON, but are facing problems when it comes as an array.
For example:
1. {"msg":"data","c":300,"stat":"k"}
2. {
"msg": [
" {\"id\":2,\"to\":\"83662\",\"from\":\"199878\",\"msg\":\"llll\",\"c\":200,\"ts\":1394536776}"
],
"c": 200,
"stat": "k",
"_ts": 1394536776
}
In the example above, sometimes I get msg as a string and sometimes as an array.
Can anyone help me? If I decide to use JSON parsing, it will be very tedious because I have around 20+ API to parse and each API contains a mininum of 50 fields.
You can use JSONObject and JSONArray classes instead of GSON to work with JSON data
for the first example
String jsonStr = "{\"msg\":\"data\",\"c\":300,\"stat\":\"k\"}";
JSONObject jsonObj = new JSONObject(jsonStr);
String msg = jsonObj.getString("msg");
Integer c = jsonObj.getInteger("c");
String stat = jsonObj.getString("stat");
For the second example
String jsonStr = ... // "your JSON data";
JSONObject jsonObj = new JSONObject(jsonStr);
JSONArray jsonArr = jsonObj.getJSONArray("msg");
JSONObject arrItem = jsonArr.getJSONObject(0);
//and so on
Also JSONObject class have method opString, opArray which does not throw exception if data you trying to get is not exist or have a wrong type
For example
JSONArray arr = jsonObj.optJSONArray("msg");
JSONObject msg = null;
if (arr != null) {
msg = arr.getJSONObject(0)
} else {
msg = jsonObj.getJSONObject("msg");
}
You can use Google GSON lib for directly parse the json to class object. This is easy and accurate.Okay do one thing both time code is different, if the code is 300 directly parse the json object without GSON. if the code is 200 the use the GSON (Define the similar java class)
String c= json.getString("c");
if(c.equals("300")
String message = status.getString("msg");
There are two ways to parce JSON.
Manually using Android OS JSON Parser Android JSON Parsing And Conversion
Using GSON Library [Library] (https://code.google.com/p/google-gson/downloads/list). This easy to handle if you know all the parameters and models of json response.
Refer the code snippet below to deserialize your json using Google's Gson library without exceptions.
String jsonStr = "your json string ";
Gson gson = new Gson();
JsonObject jsonObj = gson.fromJson (jsonStr, JsonElement.class).getAsJsonObject();
JsonElement elem = jsonObj.get("msg");
if(elem.isJsonArray()) { //**Array**
ArrayList<MyMessage> msgList = gson.fromJson(elem.toString(), new TypeToken<List<MyMessage>>(){}.getType());
} else if(elem.isJsonObject()) { //**Object**
Note note = gson.fromJson(elem.toString(), MyMessage.class);
} else { //**String**
String note = elem.toString();
}
MyMessage class
public class MyMessage {
String to;
String from;
String msg;
int id;
int c;
long ts;
// Setters and Getters
}
Related
I have the following JSON and I want to get "temp" and "pressure" in "main" key,
but I don't know how to do that.
this is my JSON :
JSONObject mainJsonObject = yourJsonObject.getJSONObject("main");
float pressure = mainJsonObject.getFloat("pressure");
float tempMin = mainJsonObject.getFloat("temp_min");
float tempMax = mainJsonObject.getFloat("temp_max");
String jsonString = ... //Your json string
JSONObject jsonObject = new JSONObject(jsonString);
JSONObject mainObject = jsonObject.getJSONObject("main");
double temp = mainObject.getDouble("temp");
//And get other fields just like the line above.
You can also use Gson library which makes parsing jsons super easy.
First define your model according to your json:
public class JSON {
public Main main;
//...
public static class Main {
public double temp;
public int pressure;
//...
}
}
Then parse the json string using Gson:
JSON object = new Gson().fromJson(jsonString, JSON.class);
double temp = object.main.temp;
First copy your json model to the JsonUtils to generate your models(classes), Then you can easily use Gson to parse your json and deserialize it in to your classes.
For example you can see this Gson Tutorial
You need to get root JSON object, and then get your nested "main" object.
It would be better if you provide your JSON file. But having tree structure, the code should look somehow like this:
//Doing it inside try/catch block, because it may throw JSONException
try{
//Getting root JSON object
JSONObject rootJSON = new JSONObject(s);
//Getting nested "main" object from root object
JSONObject mainJSON = rootJSON.getJSONObject("main");
//Getting custom String from JSON object, say "temp"
String ourString = ourObject.getString("temp");
//Then you can use it whatever way you want
Log.e("JSONObject", ourString);
//Handling JSONException
} catch(JSONException e) {
e.printStackTrace();
}
i have two situation of Json output .
one is data that found and i have a json array and a json object like this:
{"data":"yes"}[{"id":"10","number":"7","text":"text7","desc":"text7_again","user_code":"0"},{"id":"11","number":"8","text":"text8","desc":"text8_again","user_code":"1"}]
other situation is that data not found :
{"data":"no"}
just one json object.
how parse this data in android client for support two situtaion?
First, you should validate your json in http://jsonlint.com/ if you test it you will look that is a wrong json. So, for make it right, in your server your response should look something like this:
{"data":"yes","response":[{"id":"10","number":"7","text":"text7","desc":"text7_again","user_code":"0"},{"id":"11","number":"8","text":"text8","desc":"text8_again","user_code":"1"}]}
And in that case, in android
JSONObject jsonObj = new JSONObject(response);
if (jsonObj.getString("data").compareTo("yes") == 0) {
JSONArray jsonArray = jsonObj.getJSONArray("response");
//To-Do another code
}
and that's all
Here is a possible case: (you need to fix your json format)
Success -
string resultJSON =
{"success":true,
"data":[
{"id":"10","number":"7","text":"text7","desc":"text7_again","user_code":"0"},
{"id":"11","number":"8","text":"text8","desc":"text8_again","user_code":"1"}]}
Failed -
string resultJSON =
{"success":false}
Then
JSONObject jsonRoot = new JSONObject(resultJSON);
bool isSuccess = jsonRoot.getBoolean("success");
if (isSuccess) {
// do the array parser
for(int i=0; i<jsonData.lenght;i++) {
JSONObject jsonObj = jsonData.getJSONObject(i);
String id = jsonObj.getString("id"); // get the value of id
String desc = jsonObj.getString("desc"); // and so on...
}
}
I am developing the Android for Xively. I get the following text data and store into string.
{"id":111111177,"title":"G-sensor","private":"true","feed":"https://api.xively.com/v2/feeds/111111177.json","auto_feed_url":"https://api.xively.com/v2/feeds/111111177.json","status":"frozen","updated":"2014-08-05T07:14:29.783670Z","created":"2014-08-01T08:29:17.156043Z","creator":"https://xively.com/users/x22819","version":"1.0.0","datastreams":[{"id":"GPIO1","current_value":"1","at":"2014-08-05T07:14:18.991421Z","max_value":"1.0","min_value":"0.0","tags":["xyz"],"unit":{"type":"G","label":"watts"}},{"id":"GPIO2","current_value":"0","at":"2014-08-05T07:14:29.783670Z","max_value":"1.0","min_value":"0.0","tags":["xyz"],"unit":{"type":"G","label":"watts"}},{"id":"GPIO3","current_value":"1","at":"2014-08-05T06:51:08.165217Z","max_value":"1.0","min_value":"1.0"},{"id":"GPIO4","current_value":"0","at":"2014-08-05T06:51:13.029452Z","max_value":"0.0","min_value":"0.0"},{"id":"GPIO5","current_value":"1","at":"2014-08-05T06:51:20.679123Z","max_value":"1.0","min_value":"1.0"},{"id":"GPIO6","current_value":"0","at":"2014-08-05T06:51:27.057369Z","max_value":"0.0","min_value":"0.0"}],"location":{"domain":"physical"},"product_id":"w8tuBsYf835kYTjDFz9w","device_serial":"DWJAXD6N7VDZ"}
There has id and the current_value in the above data , and I want to get the data of id and the current_value from the above text like following text.
GPIO1 1
GPIO2 0
GPIO3 1
GPIO4 0
GPIO5 1
GPIO6 0
How do I capture the the data of id and the current_value from the above text ?
Can somebody teach me how to do ?
Thank in advance.
Try this:
String resultJSON = "datastreams":[{"id":"GPIO1","current_value":"1","at":"2014-08-05T07:14:18.991421Z","max_value":"1.0","min_value":"0.0","tags":["xyz"],"unit":{"type":"G","label":"watts"}},
{"id":"GPIO2","current_value":"0","at":"2014-08-05T07:14:29.783670Z","max_value":"1.0","min_value":"0.0","tags":["xyz"],"unit":{"type":"G","label":"watts"}},
{"id":"GPIO3","current_value":"1","at":"2014-08-05T06:51:08.165217Z","max_value":"1.0","min_value":"1.0"},
{"id":"GPIO4","current_value":"0","at":"2014-08-05T06:51:13.029452Z","max_value":"0.0","min_value":"0.0"},
{"id":"GPIO5","current_value":"1","at":"2014-08-05T06:51:20.679123Z","max_value":"1.0","min_value":"1.0"},
{"id":"GPIO6","current_value":"0","at":"2014-08-05T06:51:27.057369Z","max_value":"0.0","min_value":"0.0"}],"location":{"domain":"physical"},"product_id":"w8tuBsYf835kYTjDFz9w","device_serial":"DWJAXD6N7VDZ"};
JSONObject jsonRoot = new JSONObject(resultJSON);
JSONArray jsonData = jsonRoot.getJSONArray("Data");
for(int i=0; i<jsonData.lenght;i++) {
JSONObject jsonOBject = jsonData.getJSONObject(i);
Log.d(TAG, "json ("+i+") = "+jsonOBject.toString());
// do what you want with your JSONObject , i.e :add it to an ArrayList of paresed result
String ID = jsonOBject.getString("id");
}
Hope this may help you
dataList = new ArrayList<HashMap<String, String>>();
JSONObject jsonObj = new JSONObject(jsonStr);
// Getting JSON Array node
myarray = jsonObj.getJSONArray("datastreams");
// looping through All myarray
for (int i = 0; i < myarray.length(); i++) {
JSONObject c = myarray.getJSONObject(i);
String id = c.getString("id");
String date = c.getString("at");
// tmp hashmap for single data
HashMap<String, String> data = new HashMap<String, String>();
// adding each child node to HashMap key => value
data.put(TAG_ID, id);
data.put(TAG_DATE, date);
// adding data to data list
dataList.add(data);
}
The data you have is actually a JSON so you can simply parse it to java POJO. I would suggest to use one of 2 most popular open source parsers GSON or Jackson.
What you have to do is:
Create java POJOs for chosen parser. To make it easier use this online tool http://www.jsonschema2pojo.org/
Copy generated java classes to your project.
Use JSON parser e.g. GSON
Let's say you named your main class as Example, with GSON you can parse it like this:
Gson gson = new Gson();
String data = ....//your JSON data
Example example = gson.fromJson(data, Example.class);
Data you would like to get will have own Java representation and will be available through getter method, e.g.:
List<Datastream> datastreams = example.getDatastreamList();
for (DataStream data : datastreams) {
String id = data.getId();
String currentValue = data.getCurrentValue();
}
Then you can do whatever you like. Please know that GSON can also read streams, so if you already parse stream to string you can skip it and pass that stream to Gson object directly.
If you don't want redundant POJOs or their parameters, you can remove them. GSON will handle it and simply ignore these values. Just make sure that data you are interested in keep the generated structure.
That's how I would do it.
I've a json output which returns something like this :
[
{
"title":"facebook",
"description":"social networking website",
"url":"http://www.facebook.com"
},
{
"title":"WoW",
"description":"game",
"url":"http://us.battle.net/wow/"
},
{
"title":"google",
"description":"search engine",
"url":"http://www.google.com"
}
]
I am familiar with parsing json having the title object, but i've no clue about how to parse the above json as it is missing the title object. Can you please provide me with some hints/examples so i can check them and work on parsing the above code?
Note : I've checked a similar example here but it doesn't have a satisfactory solution.
Your JSON is an array of objects.
The whole idea around Gson (and other JSON serialization/deserialization) libraries is that you wind up with your own POJOs in the end.
Here's how to create a POJO that represents the object contained in the array and get a List of them from that JSON:
public class App
{
public static void main( String[] args )
{
String json = "[{\"title\":\"facebook\",\"description\":\"social networking website\"," +
"\"url\":\"http://www.facebook.com\"},{\"title\":\"WoW\",\"description\":\"game\"," +
"\"url\":\"http://us.battle.net/wow/\"},{\"title\":\"google\",\"description\":\"search engine\"," +
"\"url\":\"http://www.google.com\"}]";
// The next 3 lines are all that is required to parse your JSON
// into a List of your POJO
Gson gson = new Gson();
Type type = new TypeToken<List<WebsiteInfo>>(){}.getType();
List<WebsiteInfo> list = gson.fromJson(json, type);
// Show that you have the contents as expected.
for (WebsiteInfo i : list)
{
System.out.println(i.title + " : " + i.description);
}
}
}
// Simple POJO just for demonstration. Normally
// these would be private with getters/setters
class WebsiteInfo
{
String title;
String description;
String url;
}
Output:
facebook : social networking website
WoW : game
google : search engine
Edit to add: Because the JSON is an array of things, the use of the TypeToken is required to get to a List because generics are involved. You could actually do the following without it:
WebsiteInfo[] array = new Gson().fromJson(json, WebsiteInfo[].class);
You now have an array of your WebsiteInfo objects from one line of code. That being said, using a generic Collection or List as demonstrated is far more flexible and generally recommended.
You can read more about this in the Gson users guide
JSONArray jsonArr = new JSONArray(jsonResponse);
for(int i=0;i<jsonArr.length();i++){
JSONObject e = jsonArr.getJSONObject(i);
String title = e.getString("title");
}
use JSONObject.has(String name) to check an key name exist in current json or not for example
JSONArray jsonArray = new JSONArray("json String");
for(int i = 0 ; i < jsonArray.length() ; i++) {
JSONObject jsonobj = jsonArray.getJSONObject(i);
String title ="";
if(jsonobj.has("title")){ // check if title exist in JSONObject
String title = jsonobj.getString("title"); // get title
}
else{
title="default value here";
}
}
JSONArray array = new JSONArray(yourJson);
for(int i = 0 ; i < array.lengh(); i++) {
JSONObject product = (JSONObject) array.get(i);
.....
}
i m facing prob in parsing this obj
{
"id": 1909,
"permalink": "http:some url",
"title": "Voting begins for third phase of Bihar polls",
"excerpt": "some data.",
"date": "October 27, 2010 21:23",
"tags": [
"bihar",
"india-politics"
]
}
pls tell how to read tags value how to read value of tags
Lets say "jsonString" is equal to that example string
JSONObject json = new JSONObject(jsonString);
int id = json.getInt("id");
String permalink = json.getString("permalink");
JSONArray tags = json.getJSONArray("tags");
String firstTag = tags.getString(0);
You need to catch JSONExceptions and optionally check json.has("someproperty") before grabbing data.
u can use
Gson gson = new Gson();
List mylist = gson.fromJson(json, listtype);
u have to import gson jar which u can google it
In android Json classes are available, so no need to go elsewhere...
Step 1 : Init Json object with source string
JSONObject jObject = new JSONObject(srcString);
Step 2 : Init parent tag with another json object
if parent tag contains array the take JosnArray else JsonObject, in ur case suppose obj is parent tag then
JSONObject data = jObject.getJSONObject("obj");
Step 3 :
Now get String values
data.getString("id");
Or if array then
JSONArray dataArray = data.getJSONArray("tags");
JSONObject menuObject =dataArray.getJSONObject(0);
String firstvalue= menuObject.getString("first");
Use the JSONObject and its methods as Ian says above, however if you don't want your app to throw exceptions if any of the values are missing you can also use the 'opt' (Optional) methods, e.g.
JSONObject json = new JSONObject(jsonString);
String permalink = json.optString("permalink","");
Rather than throw an exception if 'permalink' is not found, it will return the second parameter, in this case an empty string.