Question

我正在尝试在java中创建一个注销表单，我正在使用cookie。但问题是，当我按下后退按钮时，它会将我重定向到我不想要的最后一个安全页面。

这是我的代码：小服务程序：

 @WebServlet(name="LogOut", urlPatterns={"/LogOut"})
public class LogOut extends HttpServlet {
 protected void doPost(HttpServletRequest req, HttpServletResponse response1)  
       throws ServletException, IOException {


    Cookie[] cookies = req.getCookies();
    if(cookies != null){
    for(Cookie cookie : cookies){
        if(cookie.getName().equals(req.getSession().getAttribute("email"))){
            System.out.println( req.getSession().getAttribute("email") +cookie.getValue());
        }
        cookie.setMaxAge(0);
        response1.addCookie(cookie);
    }
    }
     //invalidate the session if exists
     HttpSession session = req.getSession(false);
     System.out.println("User="+req.getSession().getAttribute("email"));
     if(session != null){
        session.invalidate();
    }
     //no encoding because we have invalidated the session
     response1.sendRedirect("index.html");
 }
}



filter:



    @WebFilter("/NoCacheFilter")
public class NoCacheFilter implements Filter {
  public void doFilter(ServletRequest req, ServletResponse res, FilterChain chain) throws IOException, ServletException {
        HttpServletResponse response = (HttpServletResponse) res;

        response.setHeader("Cache-Control", "no-cache, no-store, must-revalidate"); // HTTP 1.1.
        response.setHeader("Pragma", "no-cache"); // HTTP 1.0.
        response.setDateHeader("Expires", 0); //Proxies. 

        chain.doFilter(req, res);
    }
}

JSP：

<form action="logout" method="post">
                        <a><button type = "submit" class = "myprofile>Deconectare</button></a>
</form>

的web.xml：

  <servlet>
    <servlet-name>logout</servlet-name>
    <servlet-class>user.LogOut</servlet-class>
 </servlet>
 <filter>
    <filter-name>nocachefilter</filter-name>
    <filter-class>user.NoCacheFilter</filter-class>
 </filter>
 <filter-mapping> 
   <filter-name>nocachefilter</filter-name>
   <url-pattern>/logout</url-pattern> 
</filter-mapping> 
<servlet-mapping>
    <servlet-name>logout</servlet-name>
    <url-pattern>/logout</url-pattern>
</servlet-mapping>

有人可以帮助我吗？谢谢！

Answer 1

问题是当你点击后退按钮时，页面是从缓存而不是浏览器加载的。您可以使用此答案提供的解决方案来避免从缓存中加载：

Prevent user from seeing previously visited secured page after logout

您的servlet和过滤器应该是两个不同的类。在您的情况下，您使用的是与Servlet和Filter相同的类。

  <servlet-class>user.LogOut</servlet-class>
  <filter-class>user.LogOut</filter-class>

创建一个Servlet类......以及该类的cookie逻辑。

   public class LogOutServlet extends HttpServlet{

        protected void doPost(HttpServletRequest req,
             HttpServletResponse response1) throws ServletException, IOException {
               Cookie[] cookies = req.getCookies();
              if (cookies != null) {
              for (Cookie cookie : cookies) {
                     if(cookie.getName().equals(req.getSession().getAttribute("email"))) {
                     System.out.println(req.getSession().getAttribute("email")
                        + cookie.getValue());
            }
            cookie.setMaxAge(0);
            response1.addCookie(cookie);
         }
    }
}

你的web.xml为：您必须分别为每个过滤器和servlet指定过滤器映射和servlet映射元素。在你的文件中，logout servlet缺少servlet-mapping，过滤器缺少filter-mapping。

 <servlet>
    <servlet-name>logout</servlet-name>
    <servlet-class>user.LogOut</servlet-class>
 </servlet>
 <filter>
    <filter-name>nocachefilter</filter-name>
    <filter-class>user.NoCacheFilter</filter-class>
 </filter>
 <filter-mapping> 
   <filter-name>nocachefilter</filter-name>
   <url-pattern>/*</url-pattern>
</filter-mapping> 
<servlet-mapping>
    <servlet-name>logout</servlet-name>
    <url-pattern>/logout</url-pattern>
</servlet-mapping>

使用cookie servlets jsp

1 个答案: