Ajaxfileupload 上传文件后返回response的contentType错误问题

response 设置

1、response.setContentType("application/json;charset=UTF-8");
       response.setCharacterEncoding("UTF-8");

2、response.setContentType("text/plain;charset=UTF-8");
      response.setCharacterEncoding("UTF-8");

3、response.setContentType("text/html;charset=UTF-8");
      response.setCharacterEncoding("UTF-8");

strut2 中struts2设置response contentType 为text/html