对于不经常变化的数据,在servlet中可以为其设置合理的缓存时间值,以避免浏览器频繁向服务器发送请求,提升服务器的性能。例如:
public class ServletDemo extends HttpServlet {
public void doGet(HttpServletRequest request, HttpServletResponse response)
throws ServletException, IOException {
String data = "1235abcde";
/**
* 设置数据合理的缓存时间值,以避免浏览器频繁向服务器发送请求,提升服务器的性能
* 这里是将数据的缓存时间设置为1天(System.currentTimeMillis单位是毫秒)
*/
response.setDateHeader("Expires",System.currentTimeMillis() + 24*3600*1000);
response.getOutputStream().write(data.getBytes());
//一秒刷新页面一次
response.setHeader("refresh","1");
//二秒跳到其他页面
response.setHeader("refresh","2;URL=otherPagename");
//不缓存:
response.setDateHeader("Expires",0);//-1也可以
response.setHeader("Pragma", "No-cache");
response.setHeader("Cache-Control", "no-cache");
}
public void doPost(HttpServletRequest request, HttpServletResponse response)
throws ServletException, IOException {
doGet(request, response);
}
}