error while parsing JSON data in the bean using simple-json

Question

I am getting the following error when passing JSON data from a javascript function to a bean. ***java.lang.String cannot be cast to org.json.simple.JSONArray***. I am using json-simple to parse the data the in the backend I am using an a4j Js Function provided by rich faces to pass the JSON data as an actionParam. I am using simple-json to parse and decode the json data that is being passed.

Configurations
richfaces 3.3.3
jsf v1.2
apache tomcat v7.0.x
simple-json

Here is my javascript variable that i am sending to the bean

var a = [
                    {
                       'name': 'John',
                       'height' : '170',
                       'age' : 26
                    },{
                           'name': 'Doe',
                           'height' : '180',
                           'age' : 30
                    }
           ];


           removeServiceGroup(JSON.stringify(a));

This the a4j:jsfunction that I use to call the back end bean

<a4j:jsFunction name="removeServiceGroup" action="#{someBean.removeServiceGroup}">          
        <a4j:actionparam name="jsonData" />
    </a4j:jsFunction>

In the bean this is how i receive the data and parse it

String a = FacesContext.getCurrentInstance().getExternalContext().getRequestParameterMap().get("jsonData");
        System.out.println(a);
        JSONParser parser = new JSONParser();
        Object obj = parser.parse(a);
        JSONArray arr = (JSONArray)obj;

the system.out.println displays this on the console

"[{\"name\": \"John\", \"height\": \"170\", \"age\": 26}, {\"name\": \"Doe\", \"height\": \"180\", \"age\": 30}]"

what am i doing wrong. I went through several forums and tried doing this in several different methods, but it all ends up with the same error message

java.lang.String cannot be cast to org.json.simple.JSONArray

This is very bizarre, I just tested the same code as yours and it's working very fine. Are you sure this is really the value that is causing the error ? I just executed that code and it gave me: `Array: [{"height":"170","age":26,"name":"John"},{"height":"180","age":30,"name":"Doe"}]` as output, `arr.toString()` — Laabidi Raissi, Jun 13 '13 at 19:42
Did you create the String in Java and try the code on it or was the data passed from a javascript function on the client side. Cuz when i tried the first approach(create the string in java) , it works. The difference here looks like the data passed from the javascript has '\' which Java doesnt seem to parse. It takes it literally. Also i notices that the String sent from the javascript begins with a Double Quotes when displayed on the console, unlike the String that was created in the Java — user2317577, Jun 13 '13 at 20:42
ouups, yes I just used that `String` as it is. Please see my answer — Laabidi Raissi, Jun 13 '13 at 21:14
now this is what i don understand. Why would i have to format the input this way?. Shouldnt it be handled by itself instead of me manually having it to eliminate these extra charectrers? I am not usre if the issue here is with 'Stringify' or if its with the 'Simple JSON' that I am using — user2317577, Jun 19 '13 at 14:52

score 0 · Answer 1 · answered Jun 13 '13 at 21:13

Based on your comment, there seems to be a problem transferring JSON data using a4j:actionparam.
A workaround would be to parse the value of request param manually to remove extra things before passing it to JSONParser:

input = input.replace("\\\"", "\"");//Remove extra \
if(input.startsWith("\"")){ //Remove " at starting of the value
input = input.substring(1);
}
if(input.endsWith("\"")){//Remove ending " 
    input = input.substring(0,input.length()-1);
}

Also please check this forum post and this wiki page.

error while parsing JSON data in the bean using simple-json

1 Answers1