JavaWeb HttpSession

/**
* 使用session共享数据
*/
public class SessionDemo1 extends HttpServlet {
@Override
protected void doPost(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {
//使用session共享数据
//1.获取session
HttpSession session = req.getSession();
//2.存储数据
session.setAttribute("msg0","HelloSession");
}
}

/**
* 获取session共享的数据
*/
public class SessionDemo2 extends HttpServlet {
@Override
protected void doPost(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {
//使用session获取数据
//1.获取session
HttpSession session = req.getSession();
//2.获取数据
Object msg = session.getAttribute("msg0");
System.out.println(msg);
}
}

/**
* 使用Cookie将Session保存到浏览器，且关闭浏览器再打开后不会消失
*/
public class SessionDemo3 extends HttpServlet {
@Override
protected void doPost(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {
//1.获取Session
HttpSession session = req.getSession();
System.out.println(session);

//期望客户端关闭后，session也能相同
Cookie c = new Cookie("JSESSIONID",session.getId());
resp.addCookie(c);
}

}