jquery ajax 返回值 在页面上是乱码,该怎么解决

//加载新闻栏目    $().ready(function(){var url="/admin/ajaxGetNewsClassFather.do";var pars="random="+Math.random();var newsClassFather= $('#newsClassFather');        $.ajax({            url : url,            data : pars,            type :"POST",            success :function(res){                newsClassFather.append(res);            }        });    });

@RequestMapping("/admin/ajaxGetNewsClassFather.do")public void ajaxGetNewsClassFather(Writer writer, Model model, HttpServletRequest request, HttpServletResponse response)    {        response.setContentType("text/html");         response.setCharacterEncoding("UTF-8");        String dbname= CookieUtil.getDBname(request, response);        List<NewsClass> newsClassList= newsClassJdbcService.findbyBclassid(dbname,0);        String result="";for (NewsClass newsClass : newsClassList)        {            result+="<option value='"+ newsClass.getClassid()+"'>"+ newsClass.getClassname()+"</option>";        }try        {            writer.write(result);        }catch (IOException e)        {            e.printStackTrace();        }    }