I want to combine multiple JSON objects into a single array

Question

I'm trying to combine multiple JSON objects into one JSON array and maybe filter on the name of the data (temperature, pressure, altitude).

I tried to use JSON-Simple and Java but I can't get it to work.

Here are the pieces of JSON:

The input I want to convert:

{"temperature" : -12, "sendtimes" : 10000}
{"pressure" : 1000, "sendtimes" : 10001}
{"altitude" : 100.7, "sendtimes" : 10002}`

How I want it after conversion:

{
  "temperaturData": [
      {"temperature": -12, "sendtimes": 10000},
      {"pressure" : 1000, "sendtimes" : 10001},
      {"altitude" : 100.7, "sendtimes" : 10002},
  ]
}

I have no clue on how to do this, thanks to everyone who can help me!

Thanks for your reply, but in that question the input is already formatted, I just have a file with those three objects — Cemre Suler
– Cemre Suler, Commented Jan 1, 2019 at 11:29
Two questions: Is the input file as is and not enclosed by either {} or []? Is this {"temperature" : -12, "sendtimes" : 10000} in a single line and all other individual {} enclosed data in single lines? — Nikhil
– Nikhil, Commented Jan 1, 2019 at 12:36

Pshemo · Accepted Answer · 2019-01-01 11:54:53Z

1

Using JSON Library

JSONArray arr = new JSONArray();
JSONObject obj = new JSONObject();
obj.put("temperature", "-12");
obj.put("sendtimes", "1000");

arr.put(obj);
obj = new JSONObject();
obj.put("pressure", "1000");
obj.put("sendtimes", "1001");

arr.put(obj);

JSONObject finalObj = new JSONObject();
finalObj.put("temperaturData", arr);
System.out.println(finalObj);

Though what I suggest is that, you should better assign keys to the given inner arrays too, which will make accessing it easy and bug free.

edited Jan 1, 2019 at 11:54

Pshemo

125k25 gold badges194 silver badges280 bronze badges

answered Jan 1, 2019 at 11:49

Jatin Asija

1281 gold badge4 silver badges14 bronze badges

Sign up to request clarification or add additional context in comments.

Comments

Cognoscis · Accepted Answer · 2019-01-01 11:34:47Z

0

It is quite simple what you want to achieve. I am using JavaScript, same can be achieved with any other language using similar data structure. What you want to do is create an array and append the values to that array.

var tempData = {"temperaturData" : []}
tempData["temperaturData"].push({"temperature": -12, "sendtimes": 10000})
tempData["temperaturData"].push({"pressure" : 1000, "sendtimes" : 10001})
tempData["temperaturData"].push({"altitude" : 100.7, "sendtimes" : 10002})
JSON.stringify(tempData)

answered Jan 1, 2019 at 11:34

Cognoscis

3421 gold badge4 silver badges12 bronze badges

2 Comments

Cemre Suler Over a year ago

Thank you, but how do I do this if the dataset keeps growing larger, so everytime I run the code it converts it, no matter how many objects there are

Cognoscis Over a year ago

you can convert it into a function which adds the data to existing object

Michael Gantman · Accepted Answer · 2019-01-01 12:27:33Z

0

JSON Library mentioned by Jatin Asija is a very cool and simple JSON library that you efinitely can use to get what you want. However the de-facto standard for working with JSON in java is Jackson JSON library also known as "FasterXML/jackson". All you will have to do is to use ObjectMapperclass and its methods readValue() and writeValueAsString(Object value) to do whatever you want. Here is cool tutorial for ObjectMapper and Here are the Maven dependencies you might need to use it:

<dependency>
    <groupId>com.fasterxml.jackson.core</groupId>
    <artifactId>jackson-databind</artifactId>
</dependency>
<dependency>
    <groupId>com.fasterxml.jackson.datatype</groupId>
    <artifactId>jackson-datatype-jsr310</artifactId>
</dependency>

Here is javadoc for ObjectMapper

answered Jan 1, 2019 at 12:27

Michael Gantman

7,8682 gold badges22 silver badges42 bronze badges

4 Comments

Jatin Asija Over a year ago

Isn't ObjectMapper class is about how to serialize Java objects into JSON and deserialize JSON string into Java objects? and even if we can use it to do the above-mentioned task, but isn't that will make it very complex and tedious?

Michael Gantman Over a year ago

Jatin - yes you are correct that ObjectMapper is for serialization and de-serialization of Java classes into JSON. But your solution is the same - with JSON library you de-serialize JSON strings and then do the operations on the java objects and then serialize them back to JSON Strings. JSON library is very simple and convinient for simple operations (Also my first choice to work with JSON when I just started). But Jackson JSON is by far more powerful and definitely faster, also very tightly integrated with Spring for JSON serialization behind the scienes. So it is ultimately a better choice.

Jatin Asija Over a year ago

yes, i know it is quite the same, but in the case of ObjectMapper, one will need to create an extra bean, but with org.json, one can simply use any key and value, and as with jackson, it first parse JSON and then map it to bean, making it slower than HashMap which is used in org.json, but if anyone further want to use the bean, then jackson is better, but for the details mentioned above, this doesn't seem to be the case.

Michael Gantman Over a year ago

I guess so Jatin. So let the OP decide which one he wants

Collectives™ on Stack Overflow

I want to combine multiple JSON objects into a single array

3 Answers 3

Comments

2 Comments

4 Comments

Your Answer

Linked

Hot Network Questions

Collectives™ on Stack Overflow

3 Answers 3

Comments

2 Comments

4 Comments

Your Answer

Sign up or log in

Post as a guest

Linked

Related