Question

var  data = [
        {lastName: "Dente", name: "Al"},
        {lastName: "Noring", name: "Constance"},
        {lastName: "Haas", name: "Jack"},
        {lastName: "Tress", name: "Matt"},
        {lastName: "Turner", name: "Paige"}
    ];

this is the javascript array i want to create. How to send this data from a servlet and create the array object in javascript.

String dataString=/*prepare data */
response.getWriter().write(dataString);

How to prepare this dataString in servlet and how to create array from that string in the client ??

Answer 1

If you have the following Java class:

public class Person {
    private String lastName;
    private String name;

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

    /* getters and setters */
}

Then you can easily generate the data via the following using Gson:

List<Person> people = new ArrayList<Person>();

people.add(new Person("Smith", "John"));
people.add(new Person("Example", "An"));

String json = gson.toJson(people);

The json variable will then have a value of [{"lastName": "Smith", "name": "John"},{"lastName": "Example", "name": "An"}].

Then just send that as the response from your servlet, remember to set the content type of the request to application/json.

In order to get a handle on the data in JavaScript I would recommended using jQuery’s .getJSON() method, e.g.

$.getJSON('url of servlet', function (data) {
    console.log(data); // <-- data will be an Array containing two objects
});