Question

我写了一个过滤器，它应该在登录后创建一个新的会话修复会话固定。只有在用户登录系统时才应调用此方法：

//variables
public class GenerteNewSessionFilter implements Filter {

    public static final String NEW_SESSION_INDICATOR = "cab";

    // destroy
    public void destroy() {
        // TODO Auto-generated method stub

    }

    @SuppressWarnings({ "unchecked", "rawtypes" })
    public void doFilter(ServletRequest request, ServletResponse response, FilterChain chain) throws IOException, ServletException {

        HttpServletRequest httpRequest = (HttpServletRequest) request;
        if (httpRequest.getSession(false) != null && httpRequest.getSession(false).getAttribute(NEW_SESSION_INDICATOR) != null) {

            // copy session attributes from new session to a map.
            HttpSession session = httpRequest.getSession();

            // HashMap old = new HashMap();
            HashMap<String, Object> old = new HashMap<String, Object>();
            Enumeration keys = (Enumeration) session.getAttributeNames();
            while (keys.hasMoreElements()) {
                String key = (String) keys.nextElement();
                if (!NEW_SESSION_INDICATOR.equals(key)) {
                    old.put(key, session.getAttribute(key));
                    session.removeAttribute(key);
                }
            }

            // invalidation session and create new session.
            session.invalidate();
            session = httpRequest.getSession(true);

            // copy key value pairs from map to new session.
            for (Map.Entry entry : old.entrySet()) {
                session.setAttribute((String) entry.getKey(), entry.getValue());
            }
        }
    }

    // initiatiliazion
    public void init(FilterConfig filterConfig) throws ServletException {

    }
}

但我只想在用户登录应用程序时执行一次，请指导我如何实现它。

感谢。

Answer 1

您可以将过滤器应用于特定的servlet。因此，只将它应用于处理LoginAction的servlet，这样只有在用户登录时才会执行。

在web.xml中更改过滤器路径将<url-pattern>更改为servlet的相同路径。

<filter>
    <display-name>SessionFilter</display-name>
    <filter-name>SessionFilter</filter-name>
    <filter-class>com.session.SessionFilter</filter-class>
</filter>
<filter-mapping>
    <filter-name>NewSessionFilter</filter-name>
    <url-pattern>/your/path/LoginAction</url-pattern>
</filter-mapping>

或使用<servlet-name>而不是<url-pattern>

<filter-mapping>
    <filter-name>SessionFilter</filter-name>
    <servlet-name>LoginAction</servlet-name>
</filter-mapping>

注意您也可以将<ulr-pattern>应用于您的jsp。
<url-pattern>/your/path/login.jsp</url-pattern>

登录后创建新会话

1 个答案: