1. response.getOutputStream() 

輸出位元組流， 客戶端會下載位元組流並生成檔案儲存本地

response.setHeader("Content-disposition", "attachment;filename= ***.**");  //客戶端得到的檔名
response.setContentType("application/x-download");//設定為下載application/x-download  	
response.setContentType("text/html; charset=UTF-8");   
response.setHeader("Cache-Control","no-cache");   
response.setHeader("Cache-Control","no-store");   
response.setDateHeader("Expires", 0);   
response.setHeader("Pragma","no-cache"); 
OutputStream fos = response.getOutputStream();
fos.write("hello".getBytes());
 

直接在頁面上輸出字串

PrintWriter pw = response.getWriter();
pw.println("hello");
pw.flush();
pw.close();