JQuery JSON Servlet

<script type="text/javascript" src="js/jquery-1.10.2.js"></script>
<script type="text/javascript">
    $(document).ready(function(){
        $.post("LoginServlet", {name:"ding", pass:"ying"}, function(data){
            alert(data.label + ", " + data.value);
        }, "json");
    });
</script>

import java.io.IOException;
import java.io.PrintWriter;
import javax.servlet.ServletException;
import javax.servlet.annotation.WebServlet;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import com.dys.model.Message;
import com.google.gson.Gson;

@WebServlet("/LoginServlet")
public class LoginServlet extends HttpServlet {
    private static final long serialVersionUID = 1L;

    public void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
        this.doPost(request, response);
    }
    public void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
        String name = request.getParameter("name");
        String pass = request.getParameter("pass");

        if("ding".equals(name) && "ying".equals(pass)) {
            Message message = new Message();
            message.setLabel("系统提示");
            message.setValue("用户登录成功!");
            Gson gson = new Gson();
            String messageGSon = gson.toJson(message);
            response.setContentType("text/plain;charset=UTF-8");
            response.setCharacterEncoding("UTF-8");
            PrintWriter printWriter = response.getWriter();
            printWriter.print(messageGSon);
            printWriter.flush();
        }
    }
}