Develop Reference

AutoSuggest in Android from jsonencoded array of php

I want to use json encoded array which i am return from this link :
http://sids.roundone.asia/suggest.json?data=soft
as suggestions in android application.
(I have used json_encode($arr) function in php file and i am returning that as response for above link)
I have a problem in reading this response in java and storing it in an ArrayList.
My code is :
try {
String temp=sName.replace(" ", "%20");
URL js = new URL("https://sids.roundone.asia/suggest.json?data="+temp);
URLConnection jc = js.openConnection();
BufferedReader reader = new BufferedReader(new InputStreamReader(jc.getInputStream()));
String line = reader.readLine();
JSONObject jsonResponse = new JSONObject(line);
JSONArray jsonArray = jsonResponse.getJSONArray("results");
for(int i = 0; i < jsonResponse.length(); i++){
JSONObject r = jsonArray.getJSONObject(i);
ListData.add(new SuggestGetSet(jsonResponse.get(String.vlaueOf(iss)));
}
}

As I could see on your link, you're returning a JSON Array, instead of a JSON Object, ( "[ ]" instead of "{ }") and then in your java code you're trying to create a JSONObject here:
JSONObject jsonResponse = new JSONObject(line);
Try changing that to:
JSONArray jsonResponse = new JSONArray(line);

You return JSON array directly not a JSON Object have inner array so cast your incoming response to JSONArray directly.
JSONArray jsonResponse = new JSONArray(line);

How to extract multiple JSON Objects into String

I am reading multiple JSONObject from a file and converting into a string using StringBuilder.
These are the JSON Objects.
{"Lng":"-1.5908601","Lat":"53.7987816"}
{"Lng":"-2.5608601","Lat":"54.7987816"}
{"Lng":"-3.5608601","Lat":"55.7987816"}
{"Lng":"-4.5608601","Lat":"56.7987816"}
{"Lng":"-5.560837","Lat":"57.7987816"}
{"Lng":"-6.5608294","Lat":"58.7987772"}
{"Lng":"-7.5608506","Lat":"59.7987823"}
How to convert into a string?
Actual code is:-
BufferedReader reader = new BufferedReader(new InputStreamReader(contents.getInputStream()));
StringBuilder builder = new StringBuilder();
String line;
try {
while ((line = reader.readLine()) != null) {
builder.append(line);
}
}
catch(IOException e)
{
msg.Log(e.toString());
}
String contentsAsString = builder.toString();
//msg.Log(contentsAsString);
I tried this code
JSONObject json = new JSONObject(contentsAsString);
Iterator<String> iter = json.keys();
while(iter.hasNext())
{
String key = iter.next();
try{
Object value = json.get(key);
msg.Log("Value :- "+ value);
}catch(JSONException e)
{
//error
}
}
It just gives first object. How to loop them?

try this and see how it works for you,
BufferedReader in
= new BufferedReader(new FileReader("foo.in"));
ArrayList<JSONObject> contentsAsJsonObjects = new ArrayList<JSONObject>();
while(true)
{
String str = in.readLine();
if(str==null)break;
contentsAsJsonObjects.add(new JSONObject(str));
}
for(int i=0; i<contentsAsJsonObjects.size(); i++)
{
JSONObject json = contentsAsJsonObjects.get(i);
String lat = json.getString("Lat");
String lng = json.getString("Lng");
Log.i("TAG", lat + lng)
}

What you do is you are loading multiple JSON objects into one JSON object. This does not make sense -- it is logical that only the first object is parsed, the parser does not expect anything after the first }. Since you want to loop over the loaded objects, you should load those into a JSON array.
If you can edit the input file, convert it to the array by adding braces and commas
[
{},
{}
]
If you cannot, append the braces to the beginning of the StringBuilder and append comma to each loaded line. Consider additional condition to eliminate exceptions caused by inpropper input file.
Finally you can create JSON array from string and loop over it with this code
JSONArray array = new JSONArray(contentsAsString);
for (int i = 0; i < array.length(); ++i) {
JSONObject object = array.getJSONObject(i);
}

JSON Text data reading in Java

I have text file with JSON data in it with following format:
[ {
"belongs_to_suite": "no",
"belongs_to_suite_id": "",
"brand_family": "",
"cat_manufacturer_id": 4382,
"cat_sw_edition_id": null,
"cat_sw_product_id": 38,
"cat_sw_release_id": 47354894, } ]
I want to read only brand_family, for which I suppose I need a JSON array.
Do I need to define this format using JSON objects first?
I have downloaded org.json lib, and I have following code in which I am reading the text file, but I cannot find out how do I define format and then import all data in [{}...{}] into an array and:
FileInputStream fstream = new FileInputStream("file.txt");
BufferedReader br = new BufferedReader(new InputStreamReader(fstream));
try {
JSONObject obj = new JSONObject(br);
String n = obj.getString("version");
//int a = obj.getInt("age");
System.out.println(n);
}

As mentioned in the comments, your JSON is an array, so firstly you should call:
JSONArray array = new JSONArray(br);
Then you can do something with the size or get the first object:
JSONObject first = array.getJSONObject(0);
And finally, having the JSONObject, you can extract and process any field:
System.out.println(first.getString(""));

You can do it simply as below :
JSONParser parser=new JSONParser();
try {
JSONObject jsonObject = (JSONObject) parser.parse(new InputStreamReader(new FileInputStream("D://jsontest.txt")));
JSONArray lang= (JSONArray) jsonObject.get("obj");
for(int i=0; i<lang.size(); i++){
JSONObject obj=(JSONObject) lang.get(i);
System.out.println(obj.get("brand_family"));
}
}catch(Exception e){
e.printStackTrace();
}
Change your file to below :
{
"obj": [
{
"belongs_to_suite": "no",
"belongs_to_suite_id": "",
"brand_family": "1",
"cat_manufacturer_id": 4382,
"cat_sw_edition_id": null,
"cat_sw_product_id": 38,
"cat_sw_release_id": 47354894
},
{
"belongs_to_suite": "yes",
"belongs_to_suite_id": "",
"brand_family": "2",
"cat_manufacturer_id": 4382,
"cat_sw_edition_id": null,
"cat_sw_product_id": 38,
"cat_sw_release_id": 47354894
}
]
}

The method getJSONObject(String) is undefined for the type JSONObject

I am returning a json from my class:
#POST("/test")
#PermitAll
public JSONObject test(Map form) {
JSONObject json=new JSONObject();
json.put("key1",1);
json.put("key2",2);
return json;
}
now I want to get this json from "getInputStream" and parse it to see if key1 exists:
String output = "";
BufferedReader reader = new BufferedReader(new InputStreamReader(con.getInputStream()));
StringBuilder output = new StringBuilder();
String line = null;
while ((line = reader.readLine()) != null) {
output.append(line + "\n");
}
output=output.toString();
JSONObject jsonObj = new JSONObject();
jsonObj.put("output", output);
if (jsonObj.get("output") != null){
**//search for key1 in output**
System.out.println("key1 exists");
}else{
System.out.println("key1 doesnt exist");
}
reader.close();
How can I convert output to JSONObject and search for "key1"?
I tried following but I got errors after arrows:
JSONObject jObject = new JSONObject(output); ---> The constructor JSONObject(String) is undefined
JSONObject data = jObject.getJSONObject("data"); ---> The method getJSONObject(String) is undefined for the type JSONObject
String projectname = data.getString("name"); ----> The method getString(String) is undefined for the type JSONObject

JSONObject jsonObject = (JSONObject) JSONValue.parse(output);
Try this.
And then you can verify the existence of the field using:
jsonObject.has("key1");

You need to parse the object using a parser. Check out the documentation here: https://code.google.com/p/json-simple/wiki/DecodingExamples

Convert a .json file to a JSONArray

I used cURL to get some twitter feeds in the form of a json file ("twitter-feed.json"). I want to convert this json file to a JSONArray object. How do I do it?
I am new to Java and json. Your suggestions are most welcome.
FileInputStream infile = new FileInputStream("input/twitter-feed.json");
// parse JSON
JSONArray jsonArray = new JSONArray(string);
// use
for (int i = 0; i < jsonArray.length(); i++) {
JSONObject jsonObject = jsonArray.getJSONObject(i);
System.out.println(jsonObject.getString("id"));
System.out.println(jsonObject.getString("text"));
System.out.println(jsonObject.getString("created_at"));
}
Thanks,
PD.

You need to read the file first, convert it to String then feed it to the JSONArray (I am assuming that you are using the JSON-Java Project. The code below illustrates how to read the file and set it to JSONArray
// read the source file, source comes from streaming API delimited by newline
// done by curl https://stream.twitter.com/1/statuses/sample.json?delimited=newline -utwitterUsername:twitterPasswd
// > /Projects/StackOverflow/src/so7655570/twitter.json
FileReader f = new FileReader("/Projects/StackOverflow/src/so7655570/twitter.json");
BufferedReader br = new BufferedReader(f);
ArrayList jsonObjectArray = new ArrayList();
String currentJSONString = "";
// read the file, since I ask for newline separation, it's easier for BufferedReader
// to separate each String
while( (currentJSONString = br.readLine()) != null ) {
// create new JSONObject
JSONObject currentObject = new JSONObject(currentJSONString);
// there are more than one way to do this, right now what I am doing is adding
// each JSONObject to an ArrayList
jsonObjectArray.add(currentObject);
}
for (int i = 0; i < jsonObjectArray.size(); i++) {
JSONObject jsonObject = jsonObjectArray.get(i);
// check if it has valid ID as delete won't have one
// sample of JSON for delete :
// {"delete":{"status":{"user_id_str":"50269460","id_str":"121202089660661760","id":121202089660661760,"user_id":50269460}}}
if(jsonObject.has("id")) {
System.out.println(jsonObject.getInt("id"));
System.out.println(jsonObject.getString("text"));
System.out.println(jsonObject.getString("created_at") + "\n");
}
}
Steps explanation :
Stream API does not provide valid JSON as a whole but rather a valid one specified by the delimited field. Which is why, you can't just parse the entire result as is.
In order to parse the JSON, I use the delimited to use newline since BufferedReader has a method readLine that we could directly use to get each JSONObject
Once I get each valid JSON from each line, I create JSONObject and add it to the ArrayList
I then iterate each JSONObject in the ArrayList and print out the result. Note that if you want to use the result immediately and don't have the need to use it later, you can do the processing itself in while loop without storing them in the ArrayList which change the code to:
// read the source file, source comes from streaming API
// done by curl https://stream.twitter.com/1/statuses/sample.json?delimited=newline -utwitterUsername:twitterPasswd
// > /Projects/StackOverflow/src/so7655570/twitter.json
FileReader f = new FileReader("/Projects/StackOverflow/src/so7655570/twitter.json");
BufferedReader br = new BufferedReader(f);
String currentJSONString = "";
// read the file, since I ask for newline separation, it's easier for BufferedReader
// to separate each String
while( (currentJSONString = br.readLine()) != null ) {
// create new JSONObject
JSONObject currentObject = new JSONObject(currentJSONString);
// check if it has valid ID as delete status won't have one
if(currentObject.has("id")) {
System.out.println(currentObject.getInt("id"));
System.out.println(currentObject.getString("text"));
System.out.println(currentObject.getString("created_at") + "\n");
}
}

You may try Gson:
For just arrays you can use:
Gson gson = new Gson();
//(Deserialization)
int[] ints2 = gson.fromJson("[1,2,3,4,5]", int[].class);
To deserialize an array of objects, you can just do:
Container container = new Gson().fromJson(json, Container.class);
As shown here

Use ObjectMapper Class from jackson library like this :
//JSON from file to Object
Staff obj = mapper.readValue(new File("c:\\file.json"), Staff.class);
//JSON from URL to Object
Staff obj = mapper.readValue(new URL("http://mkyong.com/api/staff.json"), Staff.class);
//JSON from String to Object
Staff obj = mapper.readValue(jsonInString, Staff.class);