【发布时间】：2016-04-06 18:29:34
【问题描述】：
我是使用 jsp 和 servlet 的新手，所以请多多包涵。我正在构建的网站有一个登录表单来访问其余页面。当您登录时，它会使用您的用户名设置一个 cookie，其目的是让其他页面在您尝试访问它们时检查此 cookie。
登录表单在操作中运行此登录 Servlet：
public class LoginServlet extends HttpServlet implements Constants {
/**
* Processes requests for both HTTP <code>GET</code> and <code>POST</code>
* methods.
*
* @param request servlet request
* @param response servlet response
* @throws ServletException if a servlet-specific error occurs
* @throws IOException if an I/O error occurs
*/
protected void processRequest(HttpServletRequest request, HttpServletResponse response)
throws ServletException, IOException {
String Username = request.getParameter("username");
String password = request.getParameter("password");
if (StringUtils.isStringEmpty(Username) || StringUtils.isStringEmpty(password)) {
RequestDispatcher rd = request.getRequestDispatcher("/index.html");
rd.forward(request, response);
} else {
System.out.println(Username + password);
UserManager uMgr = new UserManager();
User user = uMgr.loginUser(Username, password);
if (user == null) {
RequestDispatcher rd = request.getRequestDispatcher("/login.jsp");
rd.forward(request, response);
} else {
if (user.isIsAdmin() == TRUE) {
Cookie loginCookie = new Cookie("ADMIN", Username);
//setting cookie to expiry in 30 mins
loginCookie.setMaxAge(30*60);
response.addCookie(loginCookie);
request.getSession(true).setAttribute(SESSION_ADMIN, user);
RequestDispatcher rd = request.getRequestDispatcher("index.jsp");
rd.forward(request, response);
} else {
RequestDispatcher rd = request.getRequestDispatcher("/login.jsp");
rd.forward(request, response);
}
}
}
}
// <editor-fold defaultstate="collapsed" desc="HttpServlet methods. Click on the + sign on the left to edit the code.">
/**
* Handles the HTTP <code>GET</code> method.
*
* @param request servlet request
* @param response servlet response
* @throws ServletException if a servlet-specific error occurs
* @throws IOException if an I/O error occurs
*/
@Override
protected void doGet(HttpServletRequest request, HttpServletResponse response)
throws ServletException, IOException {
processRequest(request, response);
}
/**
* Handles the HTTP <code>POST</code> method.
*
* @param request servlet request
* @param response servlet response
* @throws ServletException if a servlet-specific error occurs
* @throws IOException if an I/O error occurs
*/
@Override
protected void doPost(HttpServletRequest request, HttpServletResponse response)
throws ServletException, IOException {
processRequest(request, response);
}
/**
* Returns a short description of the servlet.
*
* @return a String containing servlet description
*/
@Override
public String getServletInfo() {
return "Short description";
}// </editor-fold>
}
在 index.jsp 页面上，我在开始的 body 标记之后运行了这段代码：
<jsp:forward page="CookieServlet"/>
这是 CookieServlet：
public class CookieServlet extends HttpServlet {
/**
* Processes requests for both HTTP <code>GET</code> and <code>POST</code>
* methods.
*
* @param request servlet request
* @param response servlet response
* @throws ServletException if a servlet-specific error occurs
* @throws IOException if an I/O error occurs
*/
protected void processRequest(HttpServletRequest request, HttpServletResponse response)
throws ServletException, IOException {
response.setContentType("text/html;charset=UTF-8");
String userName = null;
Cookie[] cookies = request.getCookies();
if(cookies !=null){
for(Cookie cookie : cookies){
if(cookie.getName().equals("ADMIN")) userName = cookie.getValue();
}
}
if(userName == null) response.sendRedirect("login.jsp");
}
// <editor-fold defaultstate="collapsed" desc="HttpServlet methods. Click on the + sign on the left to edit the code.">
/**
* Handles the HTTP <code>GET</code> method.
*
* @param request servlet request
* @param response servlet response
* @throws ServletException if a servlet-specific error occurs
* @throws IOException if an I/O error occurs
*/
@Override
protected void doGet(HttpServletRequest request, HttpServletResponse response)
throws ServletException, IOException {
processRequest(request, response);
}
/**
* Handles the HTTP <code>POST</code> method.
*
* @param request servlet request
* @param response servlet response
* @throws ServletException if a servlet-specific error occurs
* @throws IOException if an I/O error occurs
*/
@Override
protected void doPost(HttpServletRequest request, HttpServletResponse response)
throws ServletException, IOException {
processRequest(request, response);
}
/**
* Returns a short description of the servlet.
*
* @return a String containing servlet description
*/
@Override
public String getServletInfo() {
return "Short description";
}// </editor-fold>
}
登录代码有效，它为我创建了 cookie，检查 cookie 的 cookieservlet 也会检查 cookie，但没有任何 HTML 显示在任何带有 <jsp:forward page="CookieServlet"/> 的页面上。有什么错误的想法吗？
【问题讨论】：