String str=afwtHtml; 

            
            FileWriter writer;
            try {
                writer = new FileWriter("D:\\logs\\nihao2.xls");
                writer.write(str);
                writer.flush();
                writer.close();
            } catch (IOException e) {
                e.printStackTrace();
            }
            
            
            return "ExportFinished"; 

response.setHeader("Content-Disposition","attachment;filename=aaa.xls");
response.setContentType("application/vnd.ms-excel");


String afwtHtml = "<table>...</table>"

return afwtHtml;