spring MVC+ extjs 导出文件 总是返回数据 不是文件 急等

   // 导出 请求function

function submitExportData() {

	Ext.Ajax.request({

				url : "../../../../service/sec/operlog/exportOperLog",

				method: "post",

				autoAbort : true,

				xmlData : getExportDataXML(),

				// 请求成功时调用

				success : function(resp, opts) {

					Ext.Msg.alert("导出提示", "导出成功");

				},

				// 请求失败时调用

				failure : function(resp, opts) {

					Ext.Msg.alert("导出提示", "导出失败");

				}

			});

}

    public void exportOperLog(@RequestBody BasicRequest form, HttpServletResponse response)

        throws IOException

    {

        logger.debug("[security] exportOperLog() enter");

        

        //设置响应编码

        response.setCharacterEncoding("UTF-8");

        response.setContentType("application/vnd.ms-excel");

        try

        {

            response.setHeader("Content-Disposition", "attachment; filename=" + "测试下载.cvs");

        }

        catch (Exception e)

        {

            logger.error("security exportOperLog() throws Exception" + e);

        }

        

        // 所下载的文件路径

        File downFile = new File("c:/2.csv");

        ServletOutputStream servletOutputStream = null;

        InputStream inputStream = null;

        

        //如果是文件,存在

        if (downFile.isFile())

        {

            try

            {

                // 实例化文件输入流对象

                inputStream = new FileInputStream(downFile);

                servletOutputStream = response.getOutputStream();

                

                // 读取数量

                int iByteSum = 0;

                

                // 读取字节数

                int iByteRead = 0;

                

                // 缓存 1024

                byte[] bufferByte = new byte[1024];

                

                //循环读取数据

                while ((iByteRead = inputStream.read(bufferByte)) != -1)

                {

                    iByteSum += iByteRead;

                    servletOutputStream.write(bufferByte, 0, iByteRead);

                }

            }

            catch (FileNotFoundException e)

            {

                logger.error(" downLoad() inputStream appear FileNotFoundException" + e.toString());

            }

            finally

            {

                try

                {

                    //执行完毕关闭servletOutputStream

                    if (servletOutputStream != null)

                    {

                        // 关闭文件输出流

                        servletOutputStream.close();

                        

                        //释放资源

                        servletOutputStream = null;

                    }

                }

                catch (IOException e)

                {

                    logger.error(" downLoad() Close inputStream appear IOException" + e.toString());

                }

                try

                {

                    //执行完毕关闭inputStream

                    if (inputStream != null)

                    {

                        // 关闭输入流

                        inputStream.close();

                        

                        //释放资源

                        inputStream = null;

                    }

                }

                catch (IOException e)

                {

                    logger.error(" downLoad() Close inputStream appear IOException" + e.toString());

                }

            }