Returning a JSON from a Servlet

Question

How to return a JSON from a Servlet? This is my code but something is not working, I think I made mistakes in the JS code but I don't know how to correct it.

This is the servlet

protected void doGet(HttpServletRequest request, HttpServletResponse  response)throws ServletException, IOException {

    String enduser = ls.ReturnEndUser();

    Utente user = ls.getUserByUsername(enduser); 
    String json = new Gson().toJson(user);
    System.out.println("il JSON è " + json);
    response.setContentType("application/json");
    response.setCharacterEncoding("UTF-8");
    response.getWriter().write(json);

}

JS

$.get("UserServlet", function (response) {                                                                                      
document.getElementById("endusername").innerHTML = utente.nome;        
});

And this is the Utente object

public Utente(String username, String nome, String cognome, String email, String password, int gruppo1, int gruppo2, int gruppo3, int gruppo4, int gruppo5,String img_src) {
    this.id_utente = id_utente;
    this.username = username;
    this.nome = nome;
    this.cognome = cognome;
    this.email = email;
    this.password = password;
    this.gruppo1 = gruppo1;
    this.gruppo2 = gruppo2;
    this.gruppo3 = gruppo3;
    this.gruppo4 = gruppo4;
    this.gruppo5 = gruppo5;
    this.img_src= img_src;
}

score -2 · Answer 1 · answered Apr 21 '18 at 17:40

-2

$.get("UserServlet", function (response) {                                                                                      
  document.getElementById("endusername").innerHTML = utente.nome;        
});

I believe you just want to set the field 'endusername' with utente.nome. So, you don't need innerHTML here.

document.getElementById("endusername").innerHTML

should be

document.getElementById("endusername").value

PS not good with syntaxes.

answered Apr 21 '18 at 17:40

Himanshu Bhardwaj

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Well, the console shows:" Uncaught ReferenceError: utente is not defined" – Dani Apr 21 '18 at 17:51
Did you debug js and verified what are you getting in response object for js callback. – Himanshu Bhardwaj Apr 21 '18 at 18:03
Yes, from the servlet it returns correctly a JSON; I think that the mistake is still in the js but idk what is wrong – Dani Apr 21 '18 at 18:04
Solved! the js is $.get("UserServlet", function (responseJSON) { document.getElementById("endusername").innerHTML = responseJSON.nome; }); – Dani Apr 21 '18 at 18:14

Returning a JSON from a Servlet

1 Answers1