怎么转换list返回json到前台Ajax？

Question

<%

Session s=HibernateSessionFactory.getSession();
Query q=s.createQuery("from Usertab");
List list=q.list();
    s.close();
if(list.isEmpty())
out.print("Error!");

  else{
  for (Iterator it=list.iterator();it.hasNext();)
    {   Usertab ui=(Usertab)it.next();
    JSONArray json = JSONArray.fromObject(ui); 
    System.out.println(json); 
  }

}
%>

Answer 1

list转换json报错，求大神解答啊