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Inserting String variable into JSON which is in a form of String

I have a JSON payload saved as a String
String jsonBody = “{\n”
+ ” \“example\“: {\n”
+ ” \“example\“: [\n”
+ ” {\n”
+ ” \“example\“: 100,\n”
+ ” \“this_is_example_json_key\“: \“this_is_example_json_value\“,\n”
I created that by copying body from i.e Postman into
String jsonBody = "here I pasted the body";
Unfortunately I cannot have everything hardcoded there, so I have to change some values to variables. The JSON in postman looks like:
"this_is_example_json_key":"x"
And so on. Let's assume that:
String x = “this_is_example_json_value“;
If I just replace it like
+ ” \“this_is_example_json_key\“: \“ + x + \“,\n”
or something like that, the value in the body will be just this_is_example_json_value, where I need "this_is_example_json_value" (the "" marks are part of the value).
So the question is, how to set up those + / " in the String, so in the end in the value of the JSON I will end up with the value inside " ".
I've tried to play with the " / + but nothing of those were working. Variable must be passed with those " " because otherwise, the API is sending back an error.

Since java 15, if you want only use the string, you can also do in this way:
int this_is_example_json_value= 100;
String json = """
{
"this_is_example_json_key": %d
}
""".formatted(this_is_example_json_value);
Here the official jep.

Don't try to build up JSON using strings. Use a proper JSON parser.
import org.json.JSONException;
import org.json.JSONObject;
public class Eg {
public static void main(String[] args) throws JSONException {
String x = "this_is_example_json_value";
JSONObject example = new JSONObject();
example.put("this_is_example_json_key", x);
System.out.println(example.toString());
}
}
Which outputs:
{"this_is_example_json_key":"this_is_example_json_value"}
With no messing around wondering what needs to be escaped.

you can use an extra " \ " "
String x = "this_is_example_json_value";
String jsonBody = "{\n"
+ "\"example\": {\n"
+ " \"example\": [\n"
+ " {\n"
+ " \"example\": 100,\n"
+ "\"this_is_example_json_key\":" + "\"" + x + "\"" + "\n }"
+"\n ]\n }\n }";
in this case you will get a json string
{
"example": {
"example": [
{
"example": 100,
"this_is_example_json_key": "this_is_example_json_value"
}
]
}
}

How to parse custom objects from a list within a jsonstring?

I got the following json:
{
"ID": "1234567",
"dangereousCargo": true,
"numberOfPassangers": 164,
"cargo": [
{
"type": "Oil",
"amount": 8556
},
{
"type": "Chemicals",
"amount": 5593
}
]
}
From this question, I understood that it is possible to get the cargoList out of the jsonObject (if that list contains a certain type of object). But how do I get the seperate cargoObjects out of that list?
+Do the variable names of the jsonstring have to correspond with the variable names in my CargoClass? What if the jsonObject only contains type and amount and my CargoClass has more attributes?

You can iterate throws the JSONArray which represents your cargo list doing (not tested)
JSONObject json = new JSONObject(jsonString);
JSONArray cargoList = json.getJSONArray("cargo");
for(int i=0; i< cargoList.length(); i++) {
JSONObject cargo = cargoList.getJSONObject(i);
//Do something with cargo
}

But how do I get the seperate cargoObjects out of that list?
String jsonString = "{ ... }";
JSONObject json = new JSONObject(jsonString);
JSONArray cargoList = json.getJSONArray("cargo");
for(JSONObject cargo : cargoList)
{
//do something with your cargo element
}
Do the variable names of the jsonstring have to correspond with the
variable names in my CargoClass?
If you use the the get method from the JSONObject, you have to specify the exact name of the attribute in your jsonString. Following the example above:
String cargoType = cargo.getString("type");
By the way, if you want to use your already defined CargoClass, you need a Deserializer and all the attributes on your JSON must be the all present and all the same on your CargoClass: I suggest you to take a look at other SOs questions like this one.
What if the jsonObject only contains type and amount and my CargoClass
has more attributes?
The other attributes will be initialize in base of your class declaration

Using JSON Simple it is very easy to parse and read your data from your JSON. As other users have said there are a plethora of libraries out there that can accomplish this. Below is a tested example of your code.
public static void main(String[] args) throws JSONException {
String json = "{\n"
+ " ID: 1234567,\n"
+ " dangereousCargo: true,\n"
+ " numberOfPassangers: 164,\n"
+ " cargo: [\n"
+ " {\n"
+ " type: Oil,\n"
+ " amount: 8556\n"
+ " },\n"
+ " {\n"
+ " type: Chemicals,\n"
+ " amount: 5593\n"
+ " }\n"
+ " ]\n"
+ "}";
JSONObject data = new JSONObject(json);
int id = data.getInt("ID");
boolean danger = data.getBoolean("dangereousCargo");
int numOfPassengers = data.getInt("numberOfPassangers");
System.out.println("Current ID: " + id + "\n"
+ "Is Dangerous: " + danger + "\n"
+ "Number of Passengers: " + numOfPassengers + "\n");
JSONArray cargo = data.getJSONArray("cargo");
NumberFormat currency = NumberFormat.getCurrencyInstance();
for (int i = 0; i < cargo.length(); i++) {
JSONObject cargoObject = cargo.getJSONObject(i);
String type = cargoObject.getString("type");
double amount = cargoObject.getDouble("amount");
System.out.println("Current Type: " + type);
System.out.println("Current Amount: " + currency.format(amount));
}
}
}
The above code gives us the following output:
Once you have your data you can really do whatever you want with it.
Libraries
JSONSimple-https://code.google.com/p/json-simple/
GSON-https://github.com/google/gson

URL in JSON object as POST request Android

Please help me to send a JSON object in POST HTTP request through HttpClient, in Android.
The problem I am facing is that the JSON object having the URL is replaced by forward slash ,i.e
originally it should have the following value in JSON object
{"product":
{"featured_src":"https:\/\/example.com\/wp-content\/uploads\/2015\/06\/sidney-compressed.jpg,
"short_description":"this is a test","title":"Raiders from the North"}
}
i tried many options to keep it in the above format. But it always comes as {"featured_src":

We assume this is your input
private final static String JSON_DATA = "{"
+ " \"product\": ["
+ " {"
+ " \"featured_src\": \"https:\\/\\/example.com\\/wp-content"
+ "\\/uploads\\/2015\\/06\\/sidney-compressed.jpg\","
+ " \"short_description\": \"this is a test\","
+ " \"title\" : \"Raiders from the North\""
+ " }"
+ " ]"
+ "}";
You could use replace to do the trick.
YOUR_STRING.replace("\\", "");
Finally your method would look like this, by passing your string as parameter
private static String jsonUrlCorrector(String json_data) {
json_data = json_data.replace("\\", "");
return json_data;
}
Here is the input:
{"product":[{"featured_src":"https:\/\/example.com\/wp-content\/uploads\/2015\/06\/sidney-compressed.jpg","short_description": "this is a test","title":"Raiders from the North"}]}
Here is the output
{"product":[{"featured_src":"https://example.com/wp-content/uploads/2015/06/sidney-compressed.jpg","short_description":"this is a test","title":"Raiders from the North"}]}

Spring RestTemplate jackson fetch particular field

I have the following JSON in my android application and I'm using Springs for android RestTemplate. Is it somehow possible to fetch only internal list from this json ? Currently I have to create a wrapper object and then I can fetch List<Cast> casts; from it - it's a bit inconvenient.
{
"id": 550,
"cast": [
{
"cast_id": 4,
"character": "The Narrator",
"credit_id": "52fe4250c3a36847f80149f3",
"id": 819,
"name": "Edward Norton",
"order": 0,
"profile_path": "/iUiePUAQKN4GY6jorH9m23cbVli.jpg"
}
]
}

I know two solutions to solve this :
What you've done : Wrapping the list using a class
Write you're own JSON Deserializer, take a look here http://wiki.fasterxml.com/JacksonHowToCustomDeserializers
But I think the ultimate solution is in this post:
Spring/json: Convert a typed collection like List<MyPojo>

If Cast is a POJO you could try use the Jackson ObjectMapper class like this
ObjectMapper mapper = new ObjectMapper();
String jsonStr = ...
List<Cast> casts = mapper.readValue(jsonStr, new TypeReference<List<Cast>>(){});

You can grab the field, cast, and convert it like so:
final String json = "{\n" +
" \"id\": 550,\n" +
" \"cast\": [\n" +
" {\n" +
" \"cast_id\": 4,\n" +
" \"character\": \"The Narrator\",\n" +
" \"credit_id\": \"52fe4250c3a36847f80149f3\",\n" +
" \"id\": 819,\n" +
" \"name\": \"Edward Norton\",\n" +
" \"order\": 0,\n" +
" \"profile_path\": \"/iUiePUAQKN4GY6jorH9m23cbVli.jpg\"\n" +
" }\n" +
" ]\n" +
"}";
final List<Cast> casts;
try {
final JsonNode cast = objectMapper.readTree(json).get("cast");
casts = objectMapper.convertValue(cast, new TypeReference<List<Cast>>() {});
} catch (IOException e) {
throw Throwables.propagate(e);
}

Parsing a json object with an unknown name with gson

{
"lastUpdated":1404620562,
"invasions":{
"Vibrant Valley":{
"asOf":1404620562,
"type":"Penny Pincher",
"progress":"959/1000"
}
},
"error":null
}
I'm new to using Json & Gson so be patient.
So I am attempting to make an application for myself that allows me to view the information from this json file. The only problem is that it is constantly changing and sometimes there will be more then one object under invasions or sometimes there will be none. How would I parse this with gson? Thanks. Note I am grabbing values from here.
https://www.toontownrewritten.com/api/invasions
Thanks!

Use the JsonParser class
String myJson = "{" +
" \"lastUpdated\":1404620562," +
" \"invasions\":{" +
" \"Vibrant Valley\":{" +
" \"asOf\":1404620562," +
" \"type\":\"Penny Pincher\"," +
" \"progress\":\"959/1000\"" +
" }" +
" }," +
" \"error\":null" +
"}"
JsonElement jelement = new JsonParser().parse(myJson);
JsonObject jobject = jelement.getAsJsonObject();
long lastUpdated = jobject.get("lastUpdated").getAsLong();