servlet学习笔记3——用户登录网站（通过session验证登陆用户）

来源：互联网发布：java 分布式并发编辑：程序博客网时间：2024/05/05 17:31

在之前的登陆网站基础上加入session验证登录用户

首先在LoginCl.java中添加session属性，然后再Wel.java中取出session属性值进行验证，最后决定是否正确

public void process(HttpServletRequest req,HttpServletResponse res) throws ServletException,IOException{try{ //中文乱码解决 res.setContentType("text/html;charset=UTF-8"); //业务逻辑 PrintWriter pw=res.getWriter(); //返回登录界面 pw.println("<html>"); pw.println("<body>"); //得到erro信息 String info=(String)req.getParameter("info"); if(info!=null){ pw.println("<h1>你的用户名或是密码错误！</h1><br>"); } pw.println("<h1>登录界面</h1>"); pw.println("<form action=logincl method=post>"); pw.println("用户名：<input type=text name=username><br>"); pw.println("密码：<input type=password name=passwd><br>"); pw.println("<input type=submit value=loging><br>"); pw.println("</form>"); pw.println("</body>"); pw.println("</html>");}catch(Exception ex){ex.printStackTrace();}}public void doGet(HttpServletRequest req,HttpServletResponse res) throws ServletException,IOException{process(req,res);}public void doPost(HttpServletRequest req,HttpServletResponse res) throws ServletException,IOException{process(req,res);}

LoginCl.java(登陆控制验证页面)

public void process(HttpServletRequest req, HttpServletResponse res)throws ServletException, IOException { res.setContentType("text/html;charset=UTF-8");//处理中文乱码 PrintWriter pw=res.getWriter();try {// 接收用户名和密码String u = req.getParameter("username");String p = req.getParameter("passwd");if (u.equals("sp")&&p.equals("123")) {//将用户名和密码放入到session中HttpSession hs=req.getSession(true);hs.setMaxInactiveInterval(30);hs.setAttribute("name",u);res.sendRedirect("welcome?uname="+u+"&pass="+p);//会在浏览器地址栏中传输} else {res.sendRedirect("login");}} catch (Exception ex) {ex.printStackTrace();}}public void doGet(HttpServletRequest req, HttpServletResponse res)throws ServletException, IOException {process(req, res);}public void doPost(HttpServletRequest req, HttpServletResponse res)throws ServletException, IOException {process(req, res);}

Wel.java(欢迎界面)

public void process(HttpServletRequest req, HttpServletResponse res)throws ServletException, IOException {res.setContentType("text/html;charset=UTF-8");try {//从session中得到用户名HttpSession hs=req.getSession(true);String myName=(String)hs.getAttribute("name");if(myName==null){//返回登陆界面res.sendRedirect("login?info=error1");return;}//String u = req.getParameter("uname");// 得到从LoginCl传递的用户名//String p = req.getParameter("pass");PrintWriter pw = res.getWriter();pw.println("Welcom,hello<br>");pw.println("你的用户名是："+myName);//做个超链接pw.println("<br><a href="login" mce_href="login">返回重新登录</a>");} catch (Exception ex) {ex.printStackTrace();}}public void doGet(HttpServletRequest req, HttpServletResponse res)throws ServletException, IOException {process(req, res);}public void doPost(HttpServletRequest req, HttpServletResponse res)throws ServletException, IOException {process(req, res);}