private void downloadFileByOutputStream(HttpServletResponse response)
32             throws FileNotFoundException, IOException {
33         //1.獲取要下載的檔案的絕對路徑
34         String realPath = this.getServletContext().getRealPath("/download/1.JPG");
35         //2.獲取要下載的檔名
36         String fileName = realPath.substring(realPath.lastIndexOf("\\"
 
)+1);
37         //3.設定content-disposition響應頭控制瀏覽器以下載的形式開啟檔案
38         response.setHeader("content-disposition", "attachment;filename="+fileName);
39         //4.獲取要下載的檔案輸入流
40         InputStream in = new FileInputStream(realPath);
41         int len = 0;
42         //5.建立資料緩衝區
43         byte[] buffer = new
 
 byte[1024];
44         //6.通過response物件獲取OutputStream流
45         OutputStream out = response.getOutputStream();
46         //7.將FileInputStream流寫入到buffer緩衝區
47         while ((len = in.read(buffer)) > 0) {
48         //8.使用OutputStream將緩衝區的資料輸出到客戶端瀏覽器
49             out.write(buffer,0,len);
50         }
51
 
         in.close();
52     }