I have a rather large JSON object (this is a subset) I'm trying to parse:
{
"items": [
{
"Name": "Wallet",
"tags": [
"wallet",
"cardholder"
],
"features": {
"material": {
"location": "in-house"
},
"stitching": {
"location": "in-house"
}
},
"color": null,
"store": {
"address": "123 Main Street"
}
}
],
"jItem": 0
}
I have Java POJO's for all JSON objects except for the features object, which contains objects where the key is a dynamic value. My current only-POJO's code does this:
...
itemsJson = doGet(url);
ObjectMapper objMapper = new ObjectMapper();
Items items = objMapper.readValue(itemsJson, Items.class);
...
This gives me a hierarchy of Java POJO's representing my data. The one hitch is features. How can I parse the features data, with the keys as values, within this larger object? I've looked at other SO posts:
Deserialize JSON in Jackson where key is a value
Deserializing jackson dynamic key value
Jackson JSON key as value in Java
but none of these solutions have 1. an object where the key is the value and 2. an object where the key is the value is contained within an object. I do have parsing just the features working using this "just features JSON":
{
"features": {
"material": {
"location": "in-house"
},
"stitching": {
"location": "in-house"
}
}
}
with this code:
...
JsonNode jsonNodeRecord = objectMapper.readTree(App.class.getResourceAsStream("/data.json"));
List<JsonNode> recordNodes = jsonNodeRecord.findValues("features");
...
which gives me JsonNode's. This isn't ideal because I don't have my features data in a POJO.
The Question:
It's not clear to me how to integrate parsing the JSON using POJO's for everything except for features, with either the JsonNode code above or a custom deserializer as in the #1 SO link above.
Related
I need to transform a Json into another Json according to the parameter coming as part of Rest request. This service is developed in Java. I know, Jackson API can be used easily and there are some libraries also available. But my requirement is to delivery response with new Json faster as much as possible.
If I can be given few option I can measure the performance of those.
Let's assume I have this Json in data storage:
{
"bookId": "23228232-2dfa232",
"bookName": "Json Transformation",
"bookPublisher": "Tech Publication",
"bookRating": [
{
"source": "All book rank",
"maxRating": "10",
"rating": "3.4"
},
{
"source": "Tech Books",
"maxRating": "5",
"rating": "2"
},
{
"source": "Popular",
"maxRating": "3",
"rating": "1"
}
],
"bookAuthor": [
{
"name": "Jone",
"specialities": [
"Json",
"Javascript",
"Typescript",
"nodejs"
]
},
{
"name": "Mike",
"specialities": [
"Java",
"Spring",
"ElasticSearch"
]
}
]
}
Below rest calls should have respective results from this Json:
Get only authors
/authorName/23228232-2dfa232
{
authorName: [
"Jone",
"Mike"
]
}
Get Average Rating
/popularity/23228232-2dfa232
{
rating: "1.78"
}
So, the question is how to do this kind of transformation efficiently with any available library? As I mentioned above, I can simply use any Json library in Java and transform the Json, but I am not sure, if that will be efficient.
You can try little json java library for searching json data.
JsonValue json = JsonParser.parse(stringvariablewithjsondata);
List<JsonValue> authors = json.findAll(SPM.path("bookAuthor", "name")));
List<String> ratings = json.findAllLiterals(SPM.path("bookRating", "rating")));
and compute result like
JsonArray values = JsonFactory.array();
for(JsonValue value : authors) values.add(value);
JsonObject result = JsonFactory.object().add("authorName", values);
return result.toCompactString()
You can use JSON-Java --> https://www.baeldung.com/java-org-json
Or the Google JSON, aka GSON and a few others as listed here --> https://javarevisited.blogspot.com/2016/09/top-5-json-library-in-java-JEE.html
To see popularity and use statistics, which might help you chose which ones to test first: https://www.baeldung.com/java-json
You can use GSON as it easily maps JSON with POJO classes (Especially nested ones)
For a quick reference for performance comparison,
I've got the follwoing JSON structure with the corresponding DTOs in Java:
{
"kind": "object 1",
"selfLink": "some_link",
"items": [
{
"kind": "subkind 1",
"name": "server 1",
"anotherObject": {
"link": "some_link",
"isSubcollection": true,
"items": [
{
"att 1": "value",
"att2": "value",
"att3": "value"
},
{
"att5": "value" ,
"att6": "value" ,
"att7": "value" ,
"att8": "value"
}
]
}
}
]
}
Now I want to map this into corresponding DTOs using Jackson. Using the #JsonIgnoreUnknown annotation, this works fine. The problem is within the items array: How can I map different classes from the same JSON list in Jackson? Of course I could create a huge class containing both's attributes, but that would not be my way of choice.
I hope you can help me.
I am getting the following response from some service call . I am trying to parse the JSON . I am actually new to JAVA and not sure about how to parse JSON objects returned from HTTP call . I am getting the following error :
org.json.JSONException: JSONArray initial value should be a string or collection or array.
at org.json.JSONArray.<init>(JSONArray.java:197) ~[json-20180813.jar!/:na]
Code :
Object resp = hiveApiClient.getEnrollmentSearchDetails(certificate, employeeId);
logger.info("response : " + resp);
JSONArray mainArray = new JSONArray(resp);
// The nested array is at the second position : 1
JSONArray nestedArray = mainArray.getJSONArray(1);
// the interesting main JSONObject is on the first position
// of the nested array : 0
JSONObject interestingJSONObject = nestedArray.getJSONObject(0);
logger.info("XXX :{}", interestingJSONObject);
String courseId = interestingJSONObject.getJSONObject("additionalData").getString("courseId");
logger.info("XXXX :{}",courseId);
return courseId;
Response :
[
"list", [{
"#type": "com.saba.services.calendar.CalendarElementDetail",
"eventType": "ILTCLASS",
"elementName": "Microservice Application Architecture",
"elementId": "class000000000013497",
"eventId": "timel000000000103609",
"ownerID": "emplo000000000096641",
"locationId": "locat000000000003165",
"locationName": "IND-Bangalore-Karnataka",
"additionalData": {
"#type": "map",
"locationTimeZone": "tzone000000000000042",
"eventID": "class000000000013497",
"locationName": "IND-Bangalore-Karnataka",
"locationId": "locat000000000003165",
"transcriptID": "ofapr000000002962367",
"registrationID": "regdw000000001766254",
"eventName": "Microservice Application Architecture",
"moduleID": "regmd000000002147176",
"courseID": "cours000000000031995"
},
"startDate": {
"#type": "com.saba.customtypes.DateWithLocale",
"date": 1538613000000,
"locale": "03-OCT-2018",
"timeInLocale": "8:30 PM",
"dateInUserTimeZone": "03-OCT-2018",
"timeInUserTimeZone": "5:30 PM",
"dateInCustomTimeZone": null,
"timeInCustomTimeZone": null,
"customTimeZoneDate": 0,
"timeInStandardFormat": "8:30 PM",
"dateInStandardFormat": "10/03/2018"
}
}]
]
Well first of all, your json is not valid because of this}:
["list" : /* something here but anyway, not the concern here */ ]
when it should have been
{"list" : /* something here but anyway not the concern here */}
I think your problem is with the understanding of how a JSON file works and what is a json object and a json array. Please correct your JSON input so that we can provide you with insights on how to retrieve the value you need.
Additionally, I would recommend you looking into Jackson lib for parsing JSON objects to JAVA POJOs directly really easily. The link is a great tutorial to get you started here. Furthermore, jackson is already included with Spring so that you literally have nothing to install.
Edit
I misread the JSON input : I saw a : after "list" instead of a ,.
So your JSON is a proper JSON but its a quite uncommon JSON as it is loosely typed and therefore cannot be that easily parsed with standard Jackson library for example. In fact, in the main array, a string is put together with a Json Object which is a very bad practice but that's not your fault as I suppose you are not responsible for the output of this HTTP call.
So how can you actually get your value ? Well let's describe the JSON, you've got here : a JSON array containing a String and another sub JSON array. You want to take some values from the very first JSON object inside the nested json array.
This one :
{
"#type": "com.saba.services.calendar.CalendarElementDetail",
"eventType": "ILTCLASS",
"elementName": "Microservice Application Architecture",
"elementId": "class000000000013497",
"eventId": "timel000000000103609",
"ownerID": "emplo000000000096641",
"locationId": "locat000000000003165",
"locationName": "IND-Bangalore-Karnataka",
"additionalData": {
"#type": "map",
"locationTimeZone": "tzone000000000000042",
"eventID": "class000000000013497",
"locationName": "IND-Bangalore-Karnataka",
"locationId": "locat000000000003165",
"transcriptID": "ofapr000000002962367",
"registrationID": "regdw000000001766254",
"eventName": "Microservice Application Architecture",
"moduleID": "regmd000000002147176",
"courseID": "cours000000000031995"
},
"startDate": {
"#type": "com.saba.customtypes.DateWithLocale",
"date": 1538613000000,
"locale": "03-OCT-2018",
"timeInLocale": "8:30 PM",
"dateInUserTimeZone": "03-OCT-2018",
"timeInUserTimeZone": "5:30 PM",
"dateInCustomTimeZone": null,
"timeInCustomTimeZone": null,
"customTimeZoneDate": 0,
"timeInStandardFormat": "8:30 PM",
"dateInStandardFormat": "10/03/2018"
}
}
The first task here is to gather this object. Let's suppose the nested json array is always in the second position after the string and that the JSON object you want is always at the first position of the nested array which might not be the case depending on your input JSON but this was not precised in your question.
JSONArray mainArray = new JSONArray(resp);
// The nested array is at the second position : 1
JSONArray nestedArray = mainArray.getJSONArray(1);
// the interesting main JSONObject is on the first position
// of the nested array : 0
JSONObject interestingJSONObject = nestedArray.getJSONObject(0);
So now we want "courseId" from "additionnalData" Json Object :
String courseId = interestingJSONObject.getJSONObject("additionalData").getString("courseId");
And there you go!
I have the following JSON response from shipcloud.io:
[
{
"name": "dhl",
"display_name": "Deutsche Post DHL",
"services": [
"standard",
"returns",
"one_day",
"one_day_early"
],
"package_types": [
"parcel",
"bulk"
]
},
{
"name": "dpag",
"display_name": "Deutsche Post",
"services": [
"standard"
],
"package_types": [
"letter",
"parcel_letter",
"books"
]
},
{
"name": "dpd",
"display_name": "DPD - Dynamic Parcel Distribution",
"services": [
"standard",
"returns",
"one_day",
"one_day_early"
],
"package_types": [
"parcel",
"parcel_letter"
]
}
]
How can I deserialize this JSON array with Jackson? Usually I use a simple POJO and define
the property name of the list / array (#JsonProperty("blub") e.g.). Problem is, there is no property name used here...
I tried it using an empty property name, but it didn't work.
I'm just getting this error message:
Can not deserialize instance of Response.CarriersResponse out of
START_ARRAY token
If you want to use jackson, this is the solution that works for me:
ObjectMapper mapper = new ObjectMapper();
mapper.configure(DeserializationFeature.UNWRAP_ROOT_VALUE, false);
You are deserializing multiple objects of the type, so you need to do it as a list, like this
// somewhere in an example TypeReferences class
public static final TypeReference<List<Response.CarriersResponse>> CARRIER_RESPONSES = new TypeReference<List<Response.CarriersResponse>>() {
};
// elsewhere where you're calling the mapper
List<Response.CarriersResponse> responses = mapper.readValue(text, TypeReferences.CARRIER_RESPONSES);
You could instantiate it in-place, but that's a design decision between performance vs total memory consumption.
Try to deserialize to Response.CarriersResponse[] class.
Response.CarriersResponse[] responses = mapper.readValue(text, Response.CarriersResponse[].class);
I have a JSON that looks like this
[
{
"itemLabel":"Social Media",
"itemValue":90
},
{
"itemLabel":"Blogs",
"itemValue":30
},
{
"itemLabel":"Text Messaging",
"itemValue":60
},
{
"itemLabel":"Email",
"itemValue":90
},
]
I want to place all of those objects into an array to manipulate it easier in one of my code. Thus I want to do something like
[
{
"data": [
{
"itemLabel": "Social Media",
"itemValue": 90
},
{
"itemLabel": "Blogs",
"itemValue": 30
},
{
"itemLabel": "Text Messaging",
"itemValue": 60
},
{
"itemLabel": "Email",
"itemValue": 90
}
]
}
]
How do I go about to add in that data array element using Jackson? I have done mostly read using Jackson but have not done too many writes. Any help would be appreciated.
I'm not completely sure what are you intending and there is probably a more elegant solution to this (using POJOs rather than Collections and Jacksons JSON representation), but I guess this example will clear it out to you. But if you have some more complicated processing you might want to write custom (de)serializers or something like that. Written using Jackson 2.3.3
ObjectMapper mapper = new ObjectMapper();
JsonNode parsedJson = mapper.readTree(json); //parse the String or do what you already are doing to deserialize the JSON
ArrayNode outerArray = mapper.createArrayNode(); //your outer array
ObjectNode outerObject = mapper.createObjectNode(); //the object with the "data" array
outerObject.putPOJO("data",parsedJson);
outerArray.add(outerObject);
System.out.println(outerArray.toString()); //just to confirm everything is working