sending Json from servlet to javascript

Question

I am trying to send an json object array from a servlet to javascript .where I all get the array and parse . my ajax call the servlet appropriately but unable to recieve the json array at the javascript end please help

public void doPost(HttpServletRequest request, HttpServletResponse response)
        throws IOException {
    System.out.println("Post!!");
    response.setContentType("application/json");//since sendign jsonArray toString
    PrintWriter out = response.getWriter();
    try {
        Marker marker=new Marker( 40.72318,-74.03605);//

        JSONArray arrayObj=new JSONArray(); 
        arrayObj.add(marker);
        System.out.println(marker.toString());
        out.print(arrayObj);

    } finally {
        out.flush();
        out.close();
    }

}

This is my ajax call in javascript where I am trying to get the json object array form the servlet.

  $.ajax({
          url:'test',
          dataType:'json',
          type:'POST',
          success:function(data){

            <%System.out.println(" success");%>
          console.log(data);
          alert('got json hopefully');
          alert(data);
          //
      },
      error:function(jxhr){
          <%System.out.println(" faliure");%>
        console.log(jxhr.responseText);
      }

});

What are you getting as response? – SDReyes Dec 13 '12 at 22:10 — SDReyes, Dec 13 '12 at 22:10

score 1 · Answer 1 · answered Sep 12 '20 at 17:02

This worked for me, below is ajax code.

$.ajax({
    type : 'POST',
    url : "URL",
    data: {array: array},
    success : function(response)
    {
        alert("Success "+response.message);
    },
    error : function(response)
    {
        alert("Error"+response.message);
        console.log('Error');
    }
});

Servlet:

protected void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException 
{
    String[] array = request.getParameterValues("array[]");
    request.setCharacterEncoding("utf8");
    response.setContentType("application/json");
    ArrayList<String> message = new ArrayList<String>();
    message.add("response message goes here");
    PrintWriter writer = response.getWriter();
    JSONObject obj = new JSONObject();
    obj.put("message",message); 
    response.setStatus(200);
    //System.out.println(obj.get("message"));
    writer.append(obj.toString());
    writer.close();
}

For more details refer here

score 0 · Answer 2 · answered Sep 25 '13 at 19:39

This is how I make requests to the servlet and respond back with json. I use google GSON library for java and I advise you use it too. https://code.google.com/p/google-gson/

$.ajax({
                url: 'servletName', //the mapping of your servlet
                type: 'POST',
                dataType: 'json',
                data: $('#someForm').serialize(),
                success: function(data) {
                        if(data.isValid){
                     //maybe draw some html
                }else{
                    //data is not valid so give the user some kind of alert text
                }
                }

This is the servlet

protected void doPost(HttpServletRequest request, HttpServletResponse response)
        throws ServletException, IOException {
    String someInput = request.getParameter("someInput");

     Map map=new HashMap();


       if(someInput!=null){ //or whatever conditions you need
              map.put("isValid",true);
              map.put("someInput",someInput); 
       }else{
       map.put("isValid", false);

       }
       write(response,map);
   }



private void write(HttpServletResponse response, Map<String, Object> map) throws IOException {
    response.setContentType("application/json");
    response.setCharacterEncoding("UTF-8");
    response.getWriter().write(new Gson().toJson(map)); //this is how simple GSON works
}

I hope this is clear. If not, ask me in the comments.

sending Json from servlet to javascript

2 Answers2