ResponseEntity 文件下载 在IE浏览器报错，其他浏览器正常

//后台代码
@RequestMapping(value="/fileDownMeth",produces = "application/octet-stream;charset=UTF-8")
    public ResponseEntity<byte[]> download(HttpServletRequest request,
            @RequestParam(required=false) String url,
            @RequestParam(required=false) String filename,
            Model model)throws Exception {//下载文件路径
       String paths=SystemPath.getUploadPath();
       url = paths +"/"+ url;
       File file = new File(url);
       //下载显示的文件名，解决中文名称乱码问题  
       String downloadFielName = new String(filename.getBytes("UTF-8"),"iso-8859-1");
       String agent = request.getHeader("User-Agent").toUpperCase();
       boolean isMSIE = ((agent != null && agent.indexOf("MSIE") != -1 ) || ( null != agent && -1 != agent.indexOf("LIKE GECKO")));
      
       HttpHeaders headers = new HttpHeaders();  
       //application/octet-stream ： 二进制流数据（最常见的文件下载）。
       headers.setContentType(MediaType.APPLICATION_OCTET_STREAM);
       if(isMSIE) {//IE
　　　　　　　　//解决IE浏览器 下载会出现文件名中文乱码
           downloadFielName = new String(filename.getBytes("GBK"), "iso-8859-1");
           headers.setContentDispositionFormData("attachment", downloadFielName); 
           return new ResponseEntity<byte[]>(FileUtils.readFileToByteArray(file),    
                   headers, HttpStatus.OK);  
       }

       headers.setContentDispositionFormData("attachment", downloadFielName); 
       return new ResponseEntity<byte[]>(FileUtils.readFileToByteArray(file),    
               headers, HttpStatus.CREATED);  
    }

下图是因为IE不支持201状态，所以判断浏览器类型 为IE浏览器走if（isMSIE）中的返回

//前台方法
//下载上传的文件   urls:文件路径；fName:文件名称
var downFiles = function (urls,fName){
    var fURI= decodeURI(urls);
    fName=decodeURI(fName);
    window.location.href=ctx+"/sys/filedownblock/fileDownMeth?url="+encodeURI(encodeURI(fURI))+"&filename="+encodeURI(encodeURI(fName));
}