请检查代码并告诉我为什么会出现此错误？

Question

this is my servlet code

List<Group> list=  dao.findgroup(user);
        JSONObject json=(JSONObject) JSONSerializer.toJSON(list);
        ServletResponse response=ActionContext.getServletResponse();
        response.setContentType("text/JSON");
        PrintWriter out=response.getWriter(); 
        out.println(json);
        out.close();

//this is my jquery code

$.get("viewgroup.process",function(data){
        var use=$.parseJSON(data);
        $(use).each(function(i,v)
        {

        var det="<tr><td>"+v.value+"</td><td>"+v.description+"</td><td>"+v.code+"</td><td>"+v.status+"</td><td><a href='#'>reset code</a></td><td><a href='#'>change status</a></td></tr>";
        $(det).appendTo("#tablebody");
        });

Now my problem is when i am sending this request and getting a list as json object,and when I use method parseJSON it gives me error:

SyntaxError: JSON.parse: unexpected character

Can any one tell me why this error is there?

Answer 1

Pretty sure the data parameter when using $.get is already a javascript object (rather than a JSON string), so no need to parse it again:

$.get("viewgroup.process",function(data){
    var use = data;//or just use data directly rather that a new variable called use
    $(use).each(function(i,v)
    {
        var det="<tr><td>"+v.value+"</td><td>"+v.description+"</td><td>"+v.code+"</td><td>"+v.status+"</td><td><a href='#'>reset code</a></td><td><a href='#'>change status</a></td></tr>";
        $(det).appendTo("#tablebody");
    });
    //rest of code...
});

Answer 2

Change out.println(json); to out.println(json.toString()); in your servlet code. You want to send out the stringified JSON, not the actual object.

http://www.json.org/javadoc/org/json/JSONObject.html#toString%28%29