Cookie是实现记住用户名实例

「爱情、让人受尽委屈。」 2022-07-13 18:38 255阅读 0赞

## Cookie是实现记住用户名实例 ##

记住用户名的功能，登入成功后，给响应消息头添加用户名的Cookie信息，在登入页面时，加载cookie信息，通过cookie获取用户名信息，写在输入框中。

**SimpleLoginServlet**(简单的登入页面)：

@WebServlet({ "/SimpleLoginServlet", "/simple/login" })
    public class SimpleLoginServlet extends HttpServlet { 
        private static final long serialVersionUID = 1L;
    
        public SimpleLoginServlet() {
            super();
        }
    
        protected void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
            request.setCharacterEncoding("utf-8");
            response.setContentType("text/html;charset=utf-8");
    
            PrintWriter out = response.getWriter();
    
            String value = "";
            String check="checked='checked'";
    
            Cookie[] cookies = request.getCookies();
            if(cookies!=null ){
                for (int i = 0;i < cookies.length; i++) {
                    if ("username".equals(cookies[i].getName())) {
                        value = cookies[i].getValue();
                        System.out.println(value);
                    }
                }
                value = "value='"+value+"'";
            }
    
    
            out.print("<form action='"+request.getContextPath()+"/simple/login/success' method='post'>");
            out.print("用户名<input type='text' name='username' "+value+"/><br/>");
            out.print("密码<input type='password' name='password'/><br/>");
            out.print("<input type='checkbox' name='check' "+check+"/>记住用户名<br/>");
            out.print("<input type='submit' value='登入'/><br/>");
            out.print("</form>");
    
        }
    
        protected void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
            doGet(request, response);
        }
    
    }

--------------------

**LoginSuccessServlet**(登入成功页面)

@WebServlet({ "/LoginSuccessServlet", "/simple/login/success" })
    public class LoginSuccessServlet extends HttpServlet { 
        private static final long serialVersionUID = 1L;
    
        public LoginSuccessServlet() {
            super();
        }
    
        protected void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
    
            request.setCharacterEncoding("utf-8");
            response.setContentType("text/html;charset=utf-8");
            PrintWriter out = response.getWriter();
    
            String username = request.getParameter("username");
            String password = request.getParameter("password");
            String check = request.getParameter("check");
    
            Cookie cookie = new Cookie("username", username);
            cookie.setPath(request.getContextPath());
            if ("tuhao".equals(username) && "123456".equals(password)) {
                //check部位null,表示记住用户名了
                if(check!=null){
                    cookie.setMaxAge(5*60);
                    response.addCookie(cookie);
                    out.println("登入成功，已经记住用户名");
                }else {
                    cookie.setMaxAge(0);
                    response.addCookie(cookie);
                    out.print("不记住用户名");
                }
            }else {
                cookie.setMaxAge(0);
                response.addCookie(cookie);
                out.print("清除用户名");
            }
        }
    
        protected void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
            doGet(request, response);
        }
    
    }