ajax跨域请求

opurl = synInfo.action?proId=1&status="+status;
$.ajax({
type: "GET",
//async:'false',
contentType: "application/json; charset=utf-8",
url: opurl,
dataType:'jsonp',
jsonp:'jsoncallback',
//data: {"objId":objId,"sysName":sysName,"title":<%%>,"urlAddress":urlAddress,"objType":objType,"userEname":who,"jsoncallback":""},
success: function(data){
  var flag = data.flag;
  var msg = data.msg;
  if(flag == 'T'){
     alert("已经认领成功！");
}else{
alert("认领失败");
}
window.location.href="/aa.jsp";
},
    error:function(XMLHttpRequest, textStatus, errorThrown){
  alert(errorThrown);
}
});




public String jsonAttachList()
    throws IOException
  {
    String jsoncallback = Struts2Utils.getRequest().getParameter("jsoncallback");
    Struts2Utils.getResponse().setContentType("application/html;charset=UTF-8");
    JSONObject jobj = new JSONObject();
    String jb = StrUtil.doNull(jsoncallback);
    String oi = StrUtil.doNull(this.objId);
    String ot = StrUtil.doNull(this.objType);
    if ((StrUtil.isEmptyWithTrim(oi)) || (StrUtil.isEmptyWithTrim(ot))) {
      jobj.put("flag", "false");
      jobj.put("msg", "缺少必要的参数!!");
      if (StrUtil.isEmptyWithTrim(jb))
        Struts2Utils.getResponse().getWriter().print(jobj.toString());
      else {
        Struts2Utils.getResponse().getWriter().print(jb + "(" + jobj.toString() + ")");
      }
      return null;
    }
    try {
      List attachs = this.attachmentStoreManager.getAttachmentsByObjIT(oi, ot);
      JSONArray jarr = new JSONArray();
      for (Iterator iter = attachs.iterator(); iter.hasNext(); ) {
        AttachmentStore atta = (AttachmentStore)iter.next();
        AttaVO vo = copyAttaProp(atta);
        jarr.add(JSONObject.fromObject(vo));
      }
      jobj.put("total", Integer.valueOf(jarr.size()));
      jobj.put("flag", "true");
      jobj.put("msg", "恭喜，数据查询成功!!");
      jobj.put("rows", JSONArray.toArray(jarr));
      logger.info("pic list get success!");
    } catch (AttachmentStoreException e) {
      jobj.put("flag", "false");
      jobj.put("msg", "抱歉，附件查询异常!!");
      logger.error(e);
    } catch (AttachmentException e) {
      jobj.put("flag", "false");
      jobj.put("msg", "抱歉，附件查询异常!!");
      logger.error(e);
    }
    if (StrUtil.isEmptyWithTrim(jb))
      Struts2Utils.getResponse().getWriter().print(jobj.toString());
    else {
      Struts2Utils.getResponse().getWriter().print(jb + "(" + jobj.toString() + ")");
    }
    return null;
  }