String strOutFileExtName="";    
response.reset(); 
if(strOutStyle.equals("excel")){        
       response.setContentType("application/OCTET-STREAM");
     strOutFileExtName=".xls"; 
   }else{    
response.setContentType("application/csv;charset=Windows-31J");
       strOutFileExtName=".csv"; 
       }
       response.setHeader("Content-disposition", "attachment;filename=test"+strOutFileExtName);通过IE执行,会弹出对话框,其中我选择打开的时候,为什么要点击两次才能打开文件呢.