javaweb之Session URL重写

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package test.session;import java.io.IOException;import java.io.PrintWriter;import javax.servlet.ServletException;import javax.servlet.http.HttpServlet;import javax.servlet.http.HttpServletRequest;import javax.servlet.http.HttpServletResponse;//代表网站首页//URL重写：访问服务器都是通过点超链接的形式访问，不以Cookie的形式带过来，点超链接的时候带过来。一访问首页就创建session，在每个超链接后面都带上session的id号//URL重写的session只在本浏览器会话中起作用（这个问题是没有办法解决的！//但是如果浏览器没禁用Cookie就能解决，写程序的时候用上URL重写，然后按照没有禁用Cookie的方法写，//这个时候如果浏览器禁用了Cookie可以用URL重写的方式使用session，如果没禁用只有第一次访问的时候URL地址后面会重写，//第二次就访问的时候就可以用Cookie中的sessionid了）public class WelcomeServlet extends HttpServlet {public void doGet(HttpServletRequest request, HttpServletResponse response)throws ServletException, IOException {response.setCharacterEncoding("UTF-8");response.setHeader("Content-type", "text/html;charset=UTF-8");PrintWriter out = response.getWriter();// 在首页中就拿到sessionrequest.getSession();// 实现URL重写，这个重写很常见，所以SUN公司定义了一个方法，超链接后面会跟上session的id号，上面的代码已经获取session了String url1 = response.encodeURL("/day07/servlet/SessionDemo1");String url2 = response.encodeURL("/day07/servlet/SessionDemo2");out.print("<a href='" + url1 + "'>购买</a>");out.print("<a href='" + url2 + "'>结账</a>");}public void doPost(HttpServletRequest request, HttpServletResponse response)throws ServletException, IOException {doGet(request, response);}}/* * 当没有禁用Cookie的时候使用URL重写，第一次访问的时候 地址还是会被URL重写，session的id号也会被写给浏览器， * 这个时候刷新页面的话服务器发现浏览器请求中带Cookie过来了，就不会对地址进行URL重写了， * 这样就可以设置Cookie的有效期，让浏览器关了重开也能拿到原来session中的内容了 */

package test.session;import java.io.IOException;import javax.servlet.ServletException;import javax.servlet.http.Cookie;import javax.servlet.http.HttpServlet;import javax.servlet.http.HttpServletRequest;import javax.servlet.http.HttpServletResponse;import javax.servlet.http.HttpSession;//购买servletpublic class SessionDemo1 extends HttpServlet {public void doGet(HttpServletRequest request, HttpServletResponse response)throws ServletException, IOException {HttpSession session = request.getSession();String sessionId = session.getId();Cookie cookie = new Cookie("JSESSIONID", sessionId);cookie.setPath("/day07");cookie.setMaxAge(60 * 30);response.addCookie(cookie);session.setAttribute("name", "洗衣机");}public void doPost(HttpServletRequest request, HttpServletResponse response)throws ServletException, IOException {doGet(request, response);}}

package test.session;import java.io.IOException;import java.io.PrintWriter;import javax.servlet.ServletException;import javax.servlet.http.HttpServlet;import javax.servlet.http.HttpServletRequest;import javax.servlet.http.HttpServletResponse;import javax.servlet.http.HttpSession;//结账serveltpublic class SessionDemo2 extends HttpServlet {public void doGet(HttpServletRequest request, HttpServletResponse response)throws ServletException, IOException {response.setCharacterEncoding("UTF-8");response.setHeader("Content-type", "text/html;charset=UTF-8");PrintWriter out = response.getWriter();HttpSession session = request.getSession();String product = (String) session.getAttribute("name");out.print("您购买的商品是:" + product);}public void doPost(HttpServletRequest request, HttpServletResponse response)throws ServletException, IOException {doGet(request, response);}}

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