servlet设置缓存时间以及文件的下载
缓存时间的设置：
1 public void doGet(HttpServletRequest request, HttpServletResponse response) 2 throws ServletException, IOException { 3 4 response.setContentType("text/html;charset=UTF-8"); 5 PrintWriter out = response.getWriter(); 6 response.setDateHeader("Expires", System.currentTimeMillis()+60*60*1000);//缓存时间一小时 7 out.write("hello world"); 8 }
通知客户端文件的下载，此处以图片为例：
1 public void doGet(HttpServletRequest request, HttpServletResponse response) 2 throws ServletException, IOException { 3 response.setContentType("text/html"); 4 ServletContext context=getServletContext(); 5 6 String path=context.getRealPath("/picture.jpg"); 7 String fileName=path.substring(path.lastIndexOf("\\")+1); 8 InputStream in=new FileInputStream(path); 9 10 //通知客户端文件的下载 URLEncoder.encode解决文件名中文的问题 11 response.setHeader("Content-Disposition", "attachment;filename="+URLEncoder.encode(fileName, "utf-8")); 12 response.setHeader("Content-Type", "application/octet-stream"); 13 14 OutputStream out=response.getOutputStream(); 15 int length=-1; 16 byte []buffer=new byte[1024]; 17 while((length=in.read(buffer))!=-1){ 18 out.write(buffer,0,length); 19 } 20 in.close(); 21 }
