存session
//将username放到session中
HttpSession session = request.getSession(true);
session.setAttribute("username",username);
存cookie
Cookie userCookie = new Cookie("username", username); //创建cookie对象第一个参数为参数名 第二个为值
userCookie.setMaxAge(60*60*24*7); //设置cookie存活时间(7天)
response.addCookie(userCookie); //把cookie存起来
取cookie
//从请求端读取cookies数组
String cookieName = "username";
String username = null;
Cookie[] cookies = request.getCookies();
//如果cookies数组不为空,循环遍历数组
//找到其中键为username的数组,获取其对应的值存储在字符串变量username中
if(cookies != null)
{
for(int i = 0; i < cookies.length; i++)
{
Cookie cookie = cookies[i];
if(cookie.getName().equals(cookieName))
{
username = cookie.getValue();
}
}
}
//如果username为空,重定向到login.jsp
//否则显示“欢迎+username+访问我们的网站”
if(username == null)
{
response.sendRedirect("login.jsp");
}