User Session Filter实现

最新推荐文章于 2023-05-11 09:44:33 发布

原创最新推荐文章于 2023-05-11 09:44:33 发布 · 1.8k 阅读

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#session #filter #user #object #null #string

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博客给出了UserSessionFilter类的代码，该类实现了Filter接口。包含init、destroy、check和doFilter等方法，用于检查用户会话，若会话中用户对象不为空或请求路径为指定重定向页则放行，否则重定向到指定页面，还提及了web.xml。

public class UserSessionFilter implements Filter {
protected FilterConfig filterConfig;
private String redirectPage;

    public void init(FilterConfig config) {
        filterConfig = config;
        redirectPage = config.getInitParameter(
                Constants.REDIRECT);
    }

    public void destroy() {
        filterConfig = null;
    }

    private boolean check(ServletRequest request, ServletResponse response) throws
            IOException, ServletException {
        boolean result = false;
        HttpServletRequest req = (HttpServletRequest) request;

        HttpSession session = req.getSession(false);
        if (session != null) {
            Object object = session.getAttribute(Constants.USER_KEY);
            if (object != null) {
                result = true;
            }
        }

        if (redirectPage.equals(req.getServletPath())) {
            result = true;
        }
        return result;
    }

    public void doFilter(ServletRequest request, ServletResponse response,
                         FilterChain chain) throws IOException,
            ServletException {
        if (check(request, response)) {
            chain.doFilter(request, response);
        } else {
            HttpServletResponse res = (HttpServletResponse) response;
            res.sendRedirect(redirectPage);
        }
    }
}

web.xml

<filter>
    <filter-name>User Session Filter</filter-name>
    <filter-class>com.realcampaign.manager.filters.UserSessionFilter</filter-class>
    <init-param>
      <param-name>redirect</param-name>
      <param-value>/login.vm</param-value>
    </init-param>
</filter>
<filter-mapping>
    <filter-name>User Session Filter</filter-name>
    <url-pattern>*.vm</url-pattern>
</filter-mapping>