Iterate through all values of a json in Jackson

[astral compass]

<@&987246399047479336> please have a look, thanks.

[astral compass]

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[radiant dock]

What do you mean?

[olive stream]

maybe provide more context and some code if appropriate

[radiant dock]

LIke you have json file
{
"name" : "Adam",
"age" : 21,
"country" : "Canada"
}

and you want each value

Adam, 21, Canada

?

So you have getters in your object, right?

Let's keep it in this Person object that I made up there

so you can get these valuse by person.getName(), person.getAge(), person.getCountry()

It's array so it has index

So you just need to get String at index 0

with another object

[olive stream]

you know how to compare strings and arrays though right?

so whats the actual problem

do you have a class for that json to map to?

then do that

[radiant dock]

Doesn't Jackson do that tho?

Not Mapping

[olive stream]

yeah but you need to make a class for it

[radiant dock]

but Serialization and Deserialization of Json file

[olive stream]

yeah

you still need to create the class for that

[radiant dock]

So he can make like method where he will pass an Object

or a Class

I think Class would be better for SRP

[olive stream]

for this it would look smth like that:

public record Person(String name, int age, String country) {

}

[radiant dock]

DTO

[olive stream]

and then you use the object mapper

or class

doesnt matter

[radiant dock]

But @tidal jewel be careful not all Mapping works with records

[olive stream]

smth that represents your json

[radiant dock]

If you use Gradle, you can use this:
implementation 'org.modelmapper:modelmapper:3.1.1'
//Lombok
compileOnly 'org.projectlombok:lombok:1.18.28'

I used it together when I was doing mapping

[olive stream]

?

[radiant dock]

If I recall lombok is for auto getter/setters and mapper for mapping

Values

Yes

[olive stream]

the variables in the constructor should represent the entries in the json

look at the person example

{
"name" : "Adam",
"age" : 21,
"country" : "Canada"
}

public record Person(String name, int age, String country) {

}

[radiant dock]

I am sure you can find a lot of content about this

[olive stream]

yeah

[radiant dock]

https://youtu.be/5yquJa2x3Ko?t=120

Here you have video about DTO

[olive stream]

and the variable name should be the same as the json entry or use @JsonProperty("...") to use a different name for the variable

maybe try checking baeldung or smth

they have good tutorials on that

sorry ingame rn

[radiant dock]

jackson serialize and deserialize means makes Json from Objects, and Objects from Json

So now you have this Json file and to manipulate data you need Object

So you need to make an Object for Json file

ObjectMapper

[olive stream]

using the ObjectMapper, but first you need a class that represents that json

[radiant dock]

Do a class?

Your file looks like MORE OR LESS

[olive stream]

ok so can I ask you what your json represents?
just in general english, what does it store etc

[radiant dock]

public Class Example {
private String str;
private ArrayList<String> arr;

Why you downvoting me? ;_;

[olive stream]

ok so it stores a list of clients and each client got informations

let me finish that round real quick xD

[radiant dock]

public record Clients(ArrayList<String> list) {

}

[olive stream]

gonna take some longer, in a tournament rn

maybe check this
https://www.baeldung.com/jackson

[radiant dock]

https://mkyong.com/java/how-to-convert-java-object-to-from-json-jackson/

This one will be more helpful

[olive stream]

downvoting baeldung lmao

[radiant dock]

Let me have my little revange xD

and you gave link to whole tutorial

[olive stream]

these are multiple jsons right?

also what does the first number in that string mean? some kind of id of the client?

its invalid json if its in one file

{

},
{


}

this is invalid

having two multiple root elements

it must be multiple jsons

[olive stream]

ok answer this pls

are you making that json from some other service?
if so why not sending such an json:

{
  "client_id": "",
  // ... other information like in that string array
}

then also no need for array index handling

[maiden crane]

@tidal jewel lol - lmk if you wanna try my stuff

[olive stream]

also I dont know how to handle dynamic property names in jackson

[maiden crane]

can you hop in VC or share the code you have now?

or

if you are using intelliJ

click the guy there and click "start session" then DM the link

it will let me just poke your code

[olive stream]

isnt that kinda spoonfeeding

[radiant dock]

To be honest you did spoonfeeding already @olive stream

[olive stream]

with what lol

[radiant dock]

It's kinda obvious that this guy doesn't know nothing about jackson and don't even try

[olive stream]

yeah I still didnt spoonfeed lol

an example is not spoonfeeding

[radiant dock]

Ok

You are right

but still we all explained to him stuff that he could easly find in a 5 sec

and learn it by himself

[maiden crane]

Does anyone have a source for spoonfeeding bad?

other than some vague version of "they have google fuckem"

[radiant dock]

I would say, you will write this code for him, he'll learn nada, and back to here to ask another question and another

Like ObjectMapper it's first thing you have in every tutorial about Jackson

[maiden crane]

and like i've said - i don't care

[radiant dock]

He doesn't understand it and concept of Object -> Json file

[maiden crane]

Your original question doesn't make much sense without extra context

[radiant dock]

So when you will do basic work for him then how he will understand more complicated things

[olive stream]

you dont care that you just do stuff for him and he learns noting out of it
that shouldnt be the intention of a helper though

and we told you that you first need to parse it into an Object

[maiden crane]

for fucks sake my guys

i wrote up tutorials

[olive stream]

in order to work with the data

[maiden crane]

there is a minimum amount of activation energy needed to UNDO what y'all have said

[olive stream]

anyways im out

https://tenor.com/view/rotating-skull-gif-24524852

[radiant dock]

See you around downvoter :v

[maiden crane]

When that is in memory

is it a JsonObject

or is it a Map<String, String[]>

or have you not gotten that far

then your question has nothing to do with json

[olive stream]

fr

[maiden crane]

you just want to know how to iterate through the entries of a map

[olive stream]

.

[maiden crane]

okay so i reiterate

HAVE YOU NOT GOTTEN THAT FAR

okay so your question here is the same as it was before

how to load a json file into a Map<String, String[]>

right?

okay show the code you have right now

not some of it

all of it

[radiant dock]

xD

[maiden crane]

you have a blank screen?

okay so whatever

add this to your dependencies

[radiant dock]

xD

[maiden crane]

yeah do you or do you not already have code?

        <dependency>
            <groupId>dev.mccue</groupId>
            <artifactId>json</artifactId>
            <version>0.2.3</version>
        </dependency>

if you do not, replace the jackson stuff with this

🙃

[olive stream]

whats wrong with jackson

[maiden crane]

nothing - other than the fact that doing exactly what he wants to do is hard

well not hard

but it requires a TypeToken

and i do not want to field the follow up questions that will leave

okay

so first

where is the file?

is it in resources

or is it just on the filesystem

like

src/
  main/
   java/
     Stuff.java
   resources/
     file.json

or

src/
  main/
   java/
     Stuff.java
file.json

so you have the 2nd one?

okay

so first we need to open a reader into that file

try (var reader = Files.newBufferedReader(Path.of("file.json"))) {
   System.out.println(reader);
}

can you run this?

yeah

just before we go on run it

make sure it works

okay so your file is not json

it is a bunch of different json objects on their own lines

right?

okay so you want to first get a json reader from your buffered reader

        try (var reader = Files.newBufferedReader(Path.of("file.json"))) {
            JsonReader jsonReader = Json.reader(reader);
        }

and then

        try (var reader = Files.newBufferedReader(Path.of("file.json"))) {
            JsonReader jsonReader = Json.reader(reader);
            for (Json line : jsonReader) {
                System.out.println(line);
            }
        }

please loop over the reader

make sure this runs and works before we go on

okay

make sure this runs and works before we go on

please run it

share the output

delete the body for now

just have it do nothing

...are you using loser java?

upgrade to 17 or higher

in intellij

file -> project structure

project -> sdk -> add sdk -> download jdk

sure

and then also in the pom.xml make sure it says something 17 or higher

    <properties>
        <maven.compiler.source>17</maven.compiler.source>
        <maven.compiler.target>17</maven.compiler.target>
        <project.build.sourceEncoding>UTF-8</project.build.sourceEncoding>
    </properties>

okay cool

okay so first im gonna show you "the hard way"

can you copy paste this code to me

so i can change it

without typing it all up

and can you share the json

or an example

[astral compass]

I uploaded your attachments as Gist.

[maiden crane]

of your specific json that is a map of string to string[]

holy shit

no

this json is not convertable to a Map<String, String[]>

give me an example of the json that you actually are going to read in here

[astral compass]

I uploaded your attachments as Gist.

[maiden crane]

yeah

if you make me physically type out 563.513.643 i will break kneecaps

anyways

Json

that type is one of a few things

public sealed interface Json
        permits JsonBoolean, JsonNull, JsonString, JsonNumber, JsonArray, JsonObject {

read this here

what are the allowed subtypes of Json?

okay so what do you expect it to be

for the file you are reading in

not a trick question

[radiant dock]

I have to admit, I admire your dedication @maiden crane

[maiden crane]

nope

{"858687244294422539":["563.513.643","9a6b8997-1bf2-442d-897a-1a2a8b64be90","on","1"]}

this is not an array

try again

[radiant dock]

JsonObject?

[maiden crane]

yep

[radiant dock]

\o/

[olive stream]

\o/

[maiden crane]

that would work

but

instead of casting it, use the method JsonObject jsonObject = JsonDecoder.object(json);

👀

[radiant dock]

We almost there

C'mon

[neat fulcrum]

thread will stay forever, bookmark it for easy access.

[astral compass]

Closed the thread due to inactivity.

If your question was not resolved yet, feel free to just post a message to reopen it, or create a new thread. But try to improve the quality of your question to make it easier to help you 👍

[radiant dock]

He told ya, you need to use JsonObject

[maiden crane]

Yes I do

But

And I can sense the room will judge me for this

I have a bitch of a fever and no longer have the energy to go through it step by step

I am going to do the shitty thing and just show you what to do

    static String CLIENT_JSON = "file.json";

    static HashMap<String, String[]> read() {
        try (var reader = Files.newBufferedReader(Path.of(CLIENT_JSON))) {
            return new HashMap<>(
                    JsonDecoder.object(
                            Json.read(reader),
                            JsonDecoder.array(JsonDecoder::string)
                                    .map(list -> list.toArray(String[]::new))
                    )
            );
        } catch (IOException e) {
            throw new UncheckedIOException(e);
        }
    }

    static void write(HashMap<String, String[]> map) {
        try (var writer = Files.newBufferedWriter(Path.of(CLIENT_JSON))) {
            var objectBuilder = Json.objectBuilder();
            map.forEach((k, v) -> {
                objectBuilder.put(
                        k,
                        Json.of(
                            Arrays.stream(v)
                                .map(Json::of)
                                .toList()
                        )
                );
            });
            Json.write(
                    objectBuilder.build(),
                    writer
            );
        } catch (IOException e) {
            throw new UncheckedIOException(e);
        }
    }

    static void add(String k, String[] v) {
        var map = read();
        map.put(k, v);
        write(map);
    }

https://github.com/bowbahdoe/json#tutorial

here is the tutorial

[radiant dock]

Get better man!

[unreal tartan]

U can also use Jackson for this btw

Also take care emmcuee