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Convert serialized JSON string to JSON object in java

I have Json String Object as below.
"{\"SuccessData\":\"Data fetched successfully\",\"ErrorData\":\"\",\"AppData\":\"[{\\\"uniqe_id\\\":{\\\"appId\\\":4,\\\"agentId\\\":1,\\\"isActive\\\":1\\\"},\\\"pid\\\":2223,\\\"appName\\\":ACMP\\\"},{\\\"uniqe_id\\\":{\\\"appId\\\":5,\\\"agentId\\\":1,\\\"isActive\\\":1\\\"},\\\"pid\\\":2225,\\\"appName\\\":ICMP\\\"}]\"}"
I want to convert this string to JSON object using java.
I have already tried,
JSONObject jsonObj = new JSONObject(response);
I'm getting an error saying,
org.json.JSONException: A JSONObject text must begin with '{'

"{\"SuccessData\": \"Data fetched successfully\",
\"ErrorData\": \"\",
\"AppData\": \"[{\\\"uniqe_id\\\":{\\\"appId\\\":4,\\\"agentId\\\":1,\\\"isActive\\\":1\\\"},\\\"pid\\\":2223,\\\"appName\\\":ACMP\\\"},{\\\"uniqe_id\\\":{\\\"appId\\\":5,\\\"agentId\\\":1,\\\"isActive\\\":1\\\"},\\\"pid\\\":2225,\\\"appName\\\":ICMP\\\"}]\"
}"
The real problem here is that this input is not valid JSON.
Let's assume that these are the exact characters that you got in your response; i.e. the first character is a double-quote. But a valid JSON object starts with a { character. Not even whitespace is allowed according to strict reading of the syntax graph at https://json.org.
But what if that is actually a Java String literal representing the JSON?
In that case, the JSON is valid1. And what is more, your code for the JSON is correct. when I compile and run this, it works ... without throwing an exception.
import org.json.JSONObject;
public class Test {
public static void main(String[] args) {
String response = "{\"SuccessData\":\"Data fetched successfully\",\"ErrorData\":\"\",\"AppData\":\"[{\\\"uniqe_id\\\":{\\\"appId\\\":4,\\\"agentId\\\":1,\\\"isActive\\\":1\\\"},\\\"pid\\\":2223,\\\"appName\\\":ACMP\\\"},{\\\"uniqe_id\\\":{\\\"appId\\\":5,\\\"agentId\\\":1,\\\"isActive\\\":1\\\"},\\\"pid\\\":2225,\\\"appName\\\":ICMP\\\"}]\"}";
JSONObject jsonObj = new JSONObject(response);
}
}
Ergo, if you are getting a JSONException then the input is not a Java String literal.
1 - I wouldn't say it was correct. The AppData attribute has a value that is a string not a JSON object. But that string is a JSON serialization. This is technically valid, but it is a poor design choice.

I tried with the following solution and it is working,
import com.fasterxml.jackson.databind.ObjectMapper;
private JSONObject deserializeResponse(String response) {
logger.info("Parsing Serialized response object to JSON object");
JSONObject responseJson = new JSONObject();
ObjectMapper mapper = new ObjectMapper();
try {
responseJson = mapper.readValue(response.toString(),
JSONObject.class);
} catch (JsonGenerationException e) {
e.printStackTrace();
} catch (JsonMappingException e) {
e.printStackTrace();
} catch (IOException e) {
e.printStackTrace();
}
return responseJson;
}

How to serialize Dates into HashMap?

I have a use case where I get the object as a json string and consecutively needs to transform it into a HashMap. My code is as follows:
public Map<String, Object> toMap(String jsonString) {
Gson gson = new Gson();
Type type = new TypeToken<Map<String, Object>>() {
}.getType();
Map<String, Object> mapped = gson.fromJson(jsonString, type);
return mapped;
}
The date value I get from jsonString is "date": "2018-07-29T23:52:35.814Z" but upon serialization into HashMap, the "date" value is a String and not a Date object. Is there a way around it? Even solutions where Gson is not used is welcome
Sample jsonString is as follows:
{
"id": "1351",
"date": "2018-07-30T00:32:31.564Z",
"university": "US",
"typeofwork": "Report",
"title": "Thesis title",
"subject": "Masters",
"noofwords": "123"
}
To clarify, I am not getting any errors with the serialization/deserialization per se. I just want the date value to be of type java.util.Date such that a validation of if(map.get("date") instanceOf java.util.Date) will return true

If you have known exactly the property "date" is a Date, after parsing from Json, you can try somethiing like:
String dateStr = mapped.get("date");
mapped.put("date",new SimpleDateFormat("yyyy-MM-dd'T'HH:mm:ss'Z'").parse(dateStr));
If you don't want to do it manually, simply define a class that matches your Json object format (with the "date" field declared as a Date object), then:
Gson g = new GsonBuilder().setDateFormat("your date format").create();
NewClass obj = g.fromJson(jsonStr, NewClass.class);
Gson will parse the date string follow the format in setDateFormat() method.

You can do it using customDeserialzer class in Jackson:
public class CustomDeserializer extends JsonDeserializer {
#Override
public Object deserialize(JsonParser p, DeserializationContext ctxt) throws IOException, JsonProcessingException {
if(p.getCurrentName().equals("date")){
try {
return new SimpleDateFormat("yyyy-MM-dd'T'hh:mm:ss.SSS").parse(p.getText());
}catch (Exception ex){
}
return p.getText();
}
return p.getText();
}
}
Then parse like it:
ObjectMapper objectMapper = new ObjectMapper();
Map<String, Object> hashMap = new HashMap<>();
String json = "{\"date\": \"2018-07-29T23:52:35.814Z\"}";
SimpleModule module = new SimpleModule().addDeserializer(String.class, new CustomDeserializer());
objectMapper.registerModule(module);
hashMap = objectMapper.readValue(json,new TypeReference<HashMap<String,Object>>(){});
hashMap.entrySet().parallelStream().forEach(e -> System.out.println(e.getValue()));

dynimacally generte a json object

String json = "{\"loginForm\": [{\"formType\": \"questionAndAnswer\",\"id\": 164422,\"row\": [{\"label\": \"What is the name of your state?\",\"field\": [{\"id\":\"SQandA--QUESTION_1-1\",\"value\": \""+answer1+"\"}]},{\"label\": \"What is the name of your first school\",\"field\": [{\"id\":\"SQandA--QUESTION_2-2\",\"value\": \""+answer2+"\"}]}]}],"+dataset+"}";
this json contains questions and answer in it and its hard coded in my code what should i do to dynamically generate it as i want to remove the hard code and call it dynamically.

You can create a class file with your json fields and then convert the class object to json using Jackson apis.
private String getJsonFromJava (Object obj) {
ObjectMapper mapper = new ObjectMapper();
String jsonInString = "";
try {
jsonInString = mapper.writeValueAsString(obj);
} catch (JsonProcessingException e) {
System.out.println("Unable to parse object to prepare JSON string", e);
}
return jsonInString;
}

You need to write logic to create json using the inputs. If you are creating the json in JS then look at sample code below. Or you can do the same login in server side - java etc?
function createJSON() {
jsonObj = [];
$("input[questions]").each(function() {
var q= $(this).attr("Question");
var ans= $(this).val();
item = {}
item ["question"] = id;
item ["answer"] = ans;
jsonObj.push(item);
});
console.log(jsonObj);
}

Any method of passing the Json data in URL format using JSONObject?

I create a java URL class which contain my Json data and have some function to obtain back my json data for doing some data comparison, I found out it's might not support by JSONObject for passing the data into the JSONObject. Do I need to use JSONArray in my case because my JSON data have array structure as well?
try
{
JSONObject obj = new JSONObject ();
obj.readJsonFromUrl(theUrl);
System.out.println(obj.toString());
}
catch(MalformedURLException e)
{
System.out.print("your problem here ...1");
}
}
else
{
System.out.print("Can't Connect");
}
I am sure that this is the place give me the error message because it return me this error in my compiler
Exception in thread "main" java.lang.Error: Unresolved compilation problem:
The method readJsonFromUrl(URL) is undefined for the type JSONObject
there are also some warning message for that the JSONObject readJsonFromUrl method
private static JSONObject readJsonFromUrl(URL theUrl) throws IOException, JSONException {
Anyone can provide me the explaination of how the JSON data work in java? I saw quite number of Java class for JSON which make me confuse for it such as JSONObject, JSONArray , JSONValue. I search some information online but I also not very clear about it since I am very new to JSON data processing This is my sample json data and the data I need is scan_result only
{
"data_id":"a71a3c2588c6472bb4daea41a0b58835",
"file_info":{
"display_name":"",
"file_size":242,
"file_type":"Not available",
"file_type_description":"Not available",
"md5":"aa69ba384f22d0dc0551ace2fbb9ad55",
"sha1":"09ceb54e65df3d3086b222e8643acffe451a6e8a",
"sha256":"dcb46d6ae2a187f789c12f19c44bbe4b9a43bd200a3b306d5e9c1fcf811dc430",
"upload_timestamp":"2016-11-18T09:09:08.390Z"
},
"process_info":{
"blocked_reason":"",
"file_type_skipped_scan":false,
"post_processing":{
"actions_failed":"",
"actions_ran":"",
"converted_destination":"",
"converted_to":"",
"copy_move_destination":""
},
"profile":"File scan",
"progress_percentage":100,
"result":"Allowed",
"user_agent":""
},
"scan_results":{
"data_id":"a71a3c2588c6472bb4daea41a0b58835",
"progress_percentage":100,
"scan_all_result_a":"No Threat Detected",
"scan_all_result_i":0,
"scan_details":{
"Ahnlab":{
"def_time":"2016-11-08T15:00:00.000Z",
"location":"local",
"scan_result_i":0,
"scan_time":1,
"threat_found":""
},
"Avira":{
"def_time":"2016-11-08T00:00:00.000Z",
"location":"local",
"scan_result_i":0,
"scan_time":133,
"threat_found":""
},
"ClamAV":{
"def_time":"2016-11-08T10:28:00.000Z",
"location":"local",
"scan_result_i":0,
"scan_time":94,
"threat_found":""
},
"ESET":{
"def_time":"2016-11-08T00:00:00.000Z",
"location":"local",
"scan_result_i":0,
"scan_time":38,
"threat_found":""
}
},
"start_time":"2016-11-18T09:09:08.405Z",
"total_avs":4,
"total_time":250
},
"vulnerability_info":{
}
}

As mentioned here, there are many ways to solve this. Either you have to implement the read, parse operations yourself (#Roland Illig 's answer)
//you have to implement the readJSON method
InputStream is = new URL(url).openStream();
try {
BufferedReader rd = new BufferedReader(new InputStreamReader(is, Charset.forName("UTF-8")));
String jsonText = readAll(rd);
JSONObject json = new JSONObject(jsonText);
return json;
} finally {
is.close();
}
Or you could use a library. The most well-known and widely used libraries are jackson and gson.
The big picture is that you try to "map" your json Object to a class.
You have your json file:
{
"id":1,
"name":"eirini",
"hobbies":["music","philosophy","football"]
}
and a class that represents this file and will store the values (depending on the library that you use there might be different requirements, for example getters, setters etc..)
public class Person {
public int id;
public String name;
public List<String> hobbies = new ArrayList<String>();
public String toString() {
return name +" has the id: " + id + " the following hobbies" + hobbies.get(0) + " " + hobbies.get(2);
}
}
Finally in your main method:
public static void main(String[] args) throws IOException, ParseException {
ObjectMapper mapper = new ObjectMapper();
InputStream input = this.getClass().getResourceAsStream(FILE); //read your file. There are many ways to achieve this.
ObjectMapper mapper = new ObjectMapper(); // just need one
Person eirini = mapper.readValue(input, Person.class);
System.out.println(eirini.toString());

You cannot pass json in url, you can pass it in body. Writing Json to stream body and post it using regular java method.
Here is oracle community url of explanation of your problem.
Required Jar can be downloaded from here.
Test Code Follows:
URL url = new URL("https://graph.facebook.com/search?q=java&type=post");
try (InputStream is = url.openStream();
JsonReader rdr = Json.createReader(is)) {
JsonObject obj = rdr.readObject();
JsonArray results = obj.getJsonArray("data");
for (JsonObject result : results.getValuesAs(JsonObject.class)){
System.out.print(result.getJsonObject("from").getString("name"));
System.out.print(": ");
System.out.println(result.getString("message", ""));
System.out.println("-----------");
}
}

Nested JSON Request with Volley -> Escaped chars

I want to make a post request with volley to a REST API.
Therefore, I create a JSONObject and put a JSON String generated from a class in it.
JSONObject jsonObject = new JSONObject();
String json = gson.toJson(MyClazz);
try {
jsonObject.put(PARAM, json);
}
catch (JSONException e1) {
e1.printStackTrace();
}
The problem is that the correct calculated JSON String gets escaped and can't be recognized on the back end.
So toJson() gives something like:
{
"device_identifier":"324234234",
"name":"NameMe",
"list":[
{"prop":"A","prop2":-10},
{"prop":"B","prop2":-12}
]
}
The jsonObject's output is like
{
"PARAM":{
\"device_identifier\":\"324234234\",
\"name\":\"NameMe\",
\"list\":[
{\"prop\":\"A\",\"prop2\":-10},
{\"prop\":\"B\","\prop2\":-12}
]
}
}
I need the PARAM for the JSON structure so I can't give it directly to the REST-API. Any ideas how I can avoid the additional escaping?

You could wrap your MyClazz object with a simple wrapper object, and then pass that wrapped object to Gson's toJson method.
Given this class based on your example JSON,
public class MyClazz {
public String device_identifier;
public String name;
public List<Prop> list;
public class Prop {
public String prop;
public Integer prop2;
}
}
here's a possible wrapper implementation. Note the use of com.google.gson.annotations.SerializedName which tells Gson to use the PARAM key in the JSON representation.
public class MyClazzWrapper {
public MyClazzWrapper(MyClazz myClazz) {
this.myClazz = myClazz;
}
#SerializedName("PARAM")
private MyClazz myClazz;
}
And here's an example using it:
Gson gson = new GsonBuilder().setPrettyPrinting().create();
MyClazz myClazz = gson.fromJson("{\"device_identifier\":\"324234234\",\"name\":\"NameMe\",\"list\":[{\"prop\":\"A\",\"prop2\":-10},{\"prop\":\"B\",\"prop2\":-12}]}", MyClazz.class);
MyClazzWrapper wrapped = new MyClazzWrapper(myClazz);
System.out.println(gson.toJson(wrapped));
The above will print:
{
"PARAM": {
"device_identifier": "324234234",
"name": "NameMe",
"list": [
{
"prop": "A",
"prop2": -10
},
{
"prop": "B",
"prop2": -12
}
]
}
}