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Unable to retrieve data from POST request

I am working in JAVA 1.8 to write and using Apache Tomcat to run the server, I am unable to retrieve data from a POST request i.e in JSON.
I actually need it in an HashMap and I can even parse and convert it into HashMap even if it is readable in JSON. I have tried several links on the internet and I always get exception like Could not deserialize to type interface PACKAGE NAME.
#POST
#Produces("application/json")
#Consumes("application/json")
#Path("ClassifyCase")
public Rules Classify(HttpServletRequest request) {
StringBuffer jb = new StringBuffer();
String line = null;
try {
BufferedReader reader = request.getReader();
while ((line = reader.readLine()) != null)
jb.append(line);
} catch (Exception e) { System.out.println("Buffer Reader Error"); }
System.out.println("What I read: "+jb);
System.out.println("Here la la l ala ");
// System.out.println("Case: ++ "+Case.toString());
System.out.println("Here la la l ala ");
Rules foundRule = new Rules();
// List<Rules> objListRules = new ArrayList<Rules>();
try
{
DataAccessInterface objDAInterface = new RuleDataAdapter();
AbstractDataBridge objADBridge = new DatabaseStorage(objDAInterface);
// foundRule = objADBridge.Classify(Case);
logger.info("Classification done!");
}
catch(Exception ex)
{
logger.info("Error in classification");
System.out.println("Couldnt Classify Properly!");
// return
}
return foundRule;
}
Can someone please share a guide on how can I receive this data and convert it into a Map or either I can directly get a Map!

I strongly recommend you to use this library of JSON..
You can find it in Maven Repository and it's so easy to parse a JSON to a Map or to a JSONArray or JSONObject... depends of your necessity what you want to do..
Here is a example show how to parse a JSON to a HashMap
Map<String, Object> map = new JSONObject(--JSONString here--).toMap();
And that's all...
Now, if your JSON has a list of objects, i mean like a list of maps, what you just need to do is this...
JSONArray jsonArray = new JSONArray(--JSON string here--);
for(int i = 0; i < jsonArray.length(); i++){
Map<String, Object> map = jsonArray.getJSONObject(i).toMap();
}
Here is the explanation.
You take you JSON string and pass it as a parameter to the JSONArray,what JSONArray does is, take your json string a parse it to like a list
Then you make a for to get each Object of that list and parse it to a map.
Note: what the JSONObject does, is take the object of the JSONArray and parse it... you can parse it to a map or you can get each object of that map..

String jsonString = "{\n" +
"\t\"1\": \"1\",\n" +
"\t\"FPG\": \"50\",\n" +
"\t\"Symptoms\": \"Yes\"\n" +
"}";
Map<String, String> map = new Gson().fromJson(jsonString, Map.class);
for (String key: map.keySet()) {
System.out.println(map.get(key));
}

The request you send does not contain proper JSON in the body. You are missing the commas ",". It should be something like this:
{
"1":"1",
"FPG":"50",
"Symptoms":"yes"
}
Just change it and give proper JSON format to the message.
Even if the request was not in your control, I would strongly suggest that you contacted the service that creates the message and asked from them to fix it.
It would be the last resort for me to make my own deserializer to handle an "inproper" message.
An easy way to check if your JSON is properly formated is an online formatter, e.g. https://jsonformatter.org/

Access intended values in JSON file using JAVA

This is the JSON file I am working with
{"sentiment":
{"document":
{
"label": "positive",
"score": 0.53777
}
}
}
I need to access the value in label and score. using java. How can I do that?
Find below the code I am using right now:
JSONParser parser = new JSONParser();
try
{
Object object = parser
.parse(new FileReader("output_nlu_sentiment.json"));
//convert Object to JSONObject
JSONObject jsonObject = new JSONObject();
JSONObject sentimentobject= new JSONObject();
JSONObject documentobject = new JSONObject();
sentimentobject= (JSONObject) jsonObject.get("sentiment");
documentobject= (JSONObject) sentimentobject.get("document");
String label = (String) documentobject.get("label");
//float score = (float) jsonObject.get("score");
System.out.println(label);
String test = (String) sentimentobject.get("label");
System.out.println(test);
} catch(FileNotFoundException fe)
{
fe.printStackTrace();
}
catch(Exception e)
{
e.printStackTrace();
}
Why is it printing the value as null.

You might want to have a look at JacksonXml for json parsing.
Right now the problem is that you're not using the JsonObject returned by parser.parse(...).
Instead you use the get method on objects you just created. This of course means that you don't getthe valie you want to.

Try to use following code (JSONObject jsonObject = (JSONObject) object instead of JSONObject jsonObject = new JSONObject();), because you didn't use object at all, just create new empty JSONObject.
JSONParser parser = new JSONParser();
try
{
Object object = parser
.parse(new FileReader("output_nlu_sentiment.json"));
//convert Object to JSONObject
JSONObject jsonObject = (JSONObject) object;
JSONObject sentimentobject = (JSONObject) jsonObject.get("sentiment");
JSONObject documentobject= (JSONObject) sentimentobject.get("document");
String label = (String) documentobject.get("label");
System.out.println(label);
float score = (float) documentobject.get("score");
System.out.println(score );
}catch(FileNotFoundException fe)
{
fe.printStackTrace();
}
catch(Exception e)
{
e.printStackTrace();
}

You have to make use of object created in Object object = parser.parse(new FileReader("output_nlu_sentiment.json")); while creating the jsonObject
For that you can look at the code below:
Object object = parser
.parse(new FileReader("file2.json"));
//convert Object to JSONObject
JSONObject jsonObject = (JSONObject) object;
JSONObject sentimentobject= new JSONObject();
JSONObject documentobject = new JSONObject();
sentimentobject= (JSONObject) jsonObject.get("sentiment");
documentobject= (JSONObject) sentimentobject.get("document");
String label = (String) documentobject.get("label");
//float score = (float) jsonObject.get("score");
System.out.println(label);
String test = (String) sentimentobject.get("label");
You will get the positive printed on console.

you should see the content in para 'sentimentobject',force convert into class JSONObject can not get the value you want.

I prefer the FasterXML Jackson support to parse JSON into plain old Java objects (POJOs). These POJOs are often called Data Transfer Objects (DTOs) and give you a way to turn your JSON fields into properly typed members of the corresponding DTO.
Here is an example method to do that. The ObjectMapper(s) are generally maintained as statics somewhere else because FasterXML's implementation caches information to improve efficiency of object mapping operations.
static final ObjectMapper mapper = new ObjectMapper();
This is the JSON deserialization method:
public static <T> T deserializeJSON(
final ObjectMapper mapper, final InputStream json,
final Class<T> clazz)
throws JsonParseException, UnrecognizedPropertyException,
JsonMappingException, IOException
{
final String sourceMethod = "deserializeJSON";
logger.entering(sourceClass, sourceMethod);
/*
* Use Jackson support to map the JSON into a POJO for us to process.
*/
T pojoClazz;
pojoClazz = mapper.readValue(json, clazz);
logger.exiting(sourceClass, sourceMethod);
return pojoClazz;
}
Assuming I have a class called FooDTO, which has the appropriate Jackson annotations/getters/setters (note you must always provide a default empty public constructor), you can do this:
FooDTO foo = deserializeJSON(mapper, inputstream, FooDTO.class);
The deserialization throws a few different exceptions (all of which have IOException as their parent class) that you will need to handle or throw back to the caller.

Here besides of the correction alreay addressed in comments and other answers, I include some other changes you can benefit of:
It is not necessary to initialize the JSONObjects with a new instance that is going to be ovewritten in the next line.
You can use getJSONObject(), getString(), getFloat() instead of get(), in this way you don't need to cast the result.
public void parseJson() {
JSONParser parser = new JSONParser();
try
{
JSONObject jsonObject = new JSONParser().parse(new FileReader("output_nlu_sentiment.json"));
JSONObject sentimentobject= null;
JSONObject documentobject = null;
sentimentobject= jsonObject.getJSONObject("sentiment");
documentobject= sentimentobject.getJSONObject("document");
String label = documentobject.getString("label");
float score = documentobject.getFloat("score");
String output = String.format("Label: %s Score: %f", label, score);
System.out.println(output);
}catch(FileNotFoundException fe){
fe.printStackTrace();
}catch(Exception e){
e.printStackTrace();
}
}
Also for this kind of objects, where the attribute names could act as object properties, I suggest you take a look at Gson library. After modeling the json as a composition of POJOs, the parsing takes 1 line of code.

How to modify a single value in JSONObject?

I'm using Google Play Games Snapshot and I have to pass in the data I need to save by using JSON.
Here is the JSON file:
{"Date":1531043635316,"Daily bonus":2,"sound enabled":true,"total coins":2099300,"high score":0,"Btns Set":1,"leftBtnX":46,"leftBtnY":18,"leftBtnsize":1,"upBtnX":105,"upBtnY":18,"upBtnsize":1,"rightBtnX":164,"rightBtnY":18,"rightBtnsize":1,"guardBtnX":288,"guardBtnY":18,"guardBtnsize":1,"chargeBtnX":363,"chargeBtnY":18,"chargeBtnsize":1,"attackBtnX":438,"attackBtnY":18,"attackBtnsize":1,"superBtnX":438,"superBtnY":58,"superBtnsize":1,"ultimateBtnX":363,"ultimateBtnY":58,"ultimateBtnsize":1,"dpadX":80,"dpadY":40,"dpadSize":1,"gpadX":405,"gpadY":59,"gpadSize":1}
Now when I try to change only one of them using this code:
private byte[] saveToJSON(){
try {
JSONObject obj = new JSONObject();
obj.put("total coins", Settings.totalCoins);
return obj.toString().getBytes();
} catch (JSONException e) {
e.printStackTrace();
throw new RuntimeException("Error converting save data to JSON.", e);
}
}
The entire file get's changed to only this single parameter, it becomes this:
{"total coins":2099300}
Now how Can I just modify a single parameter value?
Sorry, this is the first time for me to work with JSON

JSONObject obj = new JSONObject(); make you create a new json object,that's the reason,you can change to below code:
String jsonStr = "";//your json string
JSONObject obj = new JSONObject(jsonStr);
obj.put("total coins", Settings.totalCoins);

How to get the fields of a JSON object in android studio?

I have an android app and a Web Service. When I want to edit some register I have to get the whole record from the database and put every field in a Edit Text.
The Web Service return me this to the android app
[{"id":"6","0":"6","tipo":"No Oxidado","1":"No Oxidado","fecha":"2015-02-02","2":"2015-02-02","ubicacion":"-1.555505, -6.6171","3":"-1.555505, -6.6171","persona":"Laura Morales","4":"Laura Morales","fotografia":"-","5":"-"}]
And I have a variable called "result" that have this JSON string
How do I put every field in a independent edit text in my Android App?
something like:
txtid.setText(result[0]);
txtType.setText(result[1]);
txtDate.setText(result[2]);
txtLocation.setText(result[3]);
txtPerson.setText(result[4]);
where "result" is my JSON string.

try below code.
if you have more than one json object in array
String response = "[{"id":"6","0":"6","tipo":"No Oxidado","1":"No Oxidado","fecha":"2015-02-02","2":"2015-02-02","ubicacion":"-1.555505, -6.6171","3":"-1.555505, -6.6171","persona":"Laura Morales","4":"Laura Morales","fotografia":"-","5":"-"}]"
try {
JSONArray jsonArray = new JSONArray(response);
for (int i =0; i<jsonArray.length();i++){
JSONObject jsonObject = jsonArray.getJSONObject(i);
txtid.setText(jsonObject.getString("0"));
txtType.setText(jsonObject.getString("1"));
txtDate.setText(jsonObject.getString("2"));
}
} catch (JSONException e) {
e.printStackTrace();
}
And if you have only one object in array then no need to use for loop use directly this way
try {
JSONArray jsonArray = new JSONArray(response);
JSONObject jsonObject = jsonArray.getJSONObject(0);
txtid.setText(jsonObject.getString("0"));
txtType.setText(jsonObject.getString("1"));
txtDate.setText(jsonObject.getString("2"));
} catch (JSONException e) {
e.printStackTrace();
}

there is a library to convert Json object to android model that call GSON
at first create a model with your input object like below:
class InputModel {
String id;
String 0; //it's better to change this object name
String tipo;
...
}
next, you can use Gson to bind your input to your model. it should be something like this:
InputModel mInput = new Gson().fromJson(data);
ps1: data is your input string
ps2: if you want the name of your input be different with your input name, you can use an annotation like this:
#SerializedName("id")
String productId;

Dynamic JSON issue

My JSON Structure will vary depend on the request. But the content inside each element remain same. For Example:
JSON1:
{
"h1": {
"s1":"s2"
},
"c1": {
"t1:""t2"
}
}
JSON2:
{
"h1": {
"s1":"s2"
},
"c2": {
"x1:""x2"
}
}
In the above example, elements inside h1,c1 and c2 are constant. Please let me know how to convert JSON to JAVA Object
Regards
Udhaya

First of all You need to understand Json Structure cause above format is incorrect visit this
and this
And you can use Google Gson or Json for parsing the result json String .

"t1:""t2" json format incorrect
Used
"t1":"t2"
Instead of
"t1:""t2"
and also used
"x1": "x2"
Instead of
"x1:""X2"
Code to take in java
try {
JSONObject jsonObject = new JSONObject(response);
JSONObject jsonsubObject = jsonObject.getJSONObject("h1");
String s1 = jsonsubObject.getString("s2");
JSONObject jsonsubObject1 = jsonObject.getJSONObject("c1");
String t1 = jsonsubObject1 .getString("t2");
}
catch (JSONException e) {
e.printStackTrace();
}

Use Google Gson:
Gson gson = new Gson();
ClassName object;
try {
object = gson.fromJson(json, ClassName.class);
} catch (com.google.gson.JsonSyntaxException ex) {
//the json wasn't valid json
}
String validJson = gson.toJson(obj); //obj is an instance of any class
json must be a valid JSON String

import org.json.JSONObject;
you can simple pass your data in constructor of JSONObject it automatically handle, you need to throws JSONException which may occur during conversion id format of data is not correct
String data = "{'h1':{'s1':'s2'},'c1':{'t1:''t2'}}";
JSONObject jsnobject = new JSONObject(data);