CODEWITHSUNDEEP
javascriptjavaarraysjsonrender
jquery_stack
jquery_stack

Reputation: 261

JSONSerializer to render a Java String Array

I have a Java array containing 5 strings. I want to plot this data using Flot Charts and thus I want to transfer it using render(array) from a Java file to an html file that will need Javascript. I have tried many things, and some users suggested me to just pass it to JSON in the Java file and then render it to make it easy to "digest" to Javascript.

One of the methods I've used is the following one:

JSONSerializer TestSerializer = new JSONSerializer();
    String test = TestSerializer.serialize(array);
    render(test);

I've tried to store it in a String test[] element (as an array), but it recognises the result to the serialization as a unique variable... However, the result I obtain when later on I assign into a variable ${test} in the html file to which I've done the render is the following one:

["Hello","Bye","Hi"]

With the strings "Hello", "Bye" and "Hi" placed like that, which is absolute garbage and is not useful to treat it with Javascript. Furthermore, if instead of render(array) I type renderJSON(array), all the html page goes blank but the array shows PERFECTLY as I want it, but obviously it is the only thing displayed in the content.

Do any of you have any idea of how to "transform" it or what could I do to get the desired ["Hello", "Bye", "Hi"] array in Javascript? Thanks!

Upvotes: 1

Views: 1636

Answers (1)

dazito
dazito

Reputation: 7980

Your question is not very clear. So if I understood you right, you want something like a key:value relation. Yes, you can do it with JSON and I also recommend you to use JSON.

The easy way is to use some library to do the parsing (Java->JSON) for you. I recommend you Gson.

An easy example with Gson, let's say you have a List of 4 objects type Person.

public class Person {
    private String name;

    public Person(String name) {
        this.name = name;
    }

    public String getName() {
        return name;
    }
}

Then, you add each person to a List

Person john = new Person("John");
Person mark = new Person("Mark");
Person maria = new Person("Maria");
Person beth = new Person("Beth");

List<Person> personList = new ArrayList<>();
personList.add(john);
personList.add(mark);
personList.add(maria);
personList.add(beth);

Now comes the parsing, let's use Gson.

Gson gson = new Gson();
String jsonString = gson.toJson(personList);

At this point you already have the String with the JSON code in it. As I'm not sure if you just want the JSON String or the actual JSON Object, in case you want the JSON Object you can do the following:

JsonParser parser = new JsonParser();
JsonArray jsonArray = parser.parse(jsonString).getAsJsonArray();

They both hold the same information, but one in a String and the other in a JSON Object.

To make sure, you can do:

System.out.println("String: " + jsonString);
System.out.println("JSONArray.toString(): " + jsonArray.toString());

Which will print:

String: [{"name":"John"},{"name":"Mark"},{"name":"Maria"},{"name":"Beth"}]
JSONArray.toString(): [{"name":"John"},{"name":"Mark"},{"name":"Maria"},{"name":"Beth"}]

PS; If you want to change the key to something else you just need to change it on the Person class. Lets say you don't want you key to be as "name" but "firstName". You just go to the Person class and change the variable name to firstName

PS2; Using a parsing library for such a small example may look like an overkill but when your JSON object gets a little bit more complex it is a time saver.

Upvotes: 1

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