只要客户端一旦连接上服务器,服务器就会自动产生Session;
一个连接对应一个session,session可以在一个会话中传递信息;
通过setAttribute设置值。
通过getAttribute获得值。
由服务器端控制,服务器如果重启了,信息就会丢失!
public class SessionTest extends HttpServlet {
@Override
protected void doGet(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {
doPost(req,resp);
}
@Override
protected void doPost(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {
//解决乱码问题:
req.setCharacterEncoding("UTF-8");
resp.setCharacterEncoding("UTF-8");
//Session由服务器自动创建,如何获得session
//HttpSession 得到的sessioin对象
HttpSession session = req.getSession();
//得到sessionID,一次会话,一个seesionID;
String id = session.getId();
resp.getWriter().println("获得的sessionId:\n"+id);
String name = "qinjiang";
//向session中存入一个值;
session.setAttribute("name",name);
resp.getWriter().println("存入信息成功:"+name);
}
}
//获得session存入的值
public class SessionTest2 extends HttpServlet {
@Override
protected void doGet(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {
doPost(req,resp);
}
@Override
protected void doPost(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {
//解决乱码问题:
req.setCharacterEncoding("UTF-8");
resp.setCharacterEncoding("UTF-8");
//获得
HttpSession session = req.getSession();
System.out.println("得到的SessionID:"+session.getId());
String name = (String) session.getAttribute("name");
resp.getWriter().println("得到的session存入的信息"+name);
//Servlet < Seesion < WebContext
}
}
会话注销方法一:
- session.invalidate();//通过代码注销会话
会话注销方法二:
2.<!--session-config可以设置会话自动过期,时间分钟为单位--> <session-config> <session-timeout>1</session-timeout> </session-config>