SpringMVC配置拦截器实现登录控制

SpringMVC读取Cookie判断用户是否登录，对每一个action都要进行判断。之前使用jstl标签在页面上判断session如果没有登录就使用如下代码跳转到登录页面。

<c:if test="${sessionScope.login == null || sessionScope.login == false}">
    <!-- 未登录 -->
    <c:redirect url="/login"/>
</c:if>
<c:if test="${sessionScope.login}">
    <!-- 已登录 -->
</c:if>

但是测试发现如果session过期，页面渲染就会无故中断并且不会跳转到登录页面。故尝试使用拦截器来进行登录判断。

拦截器配置文件如下

<!-- <mvc:mapping path="/**" /> 如果只写一个*，则不能拦截类似/*/*的请求。静态资源的请求需要判断不进行拦截 -->
<mvc:interceptors>
    <mvc:interceptor>
        <mvc:mapping path="/**" />
        <bean class="com.ts.settle.tools.interceptor.LoginInterceptor">
            <property name="excludedUrls">
                <list>
                    <value>/login</value>
                    <value>/static/</value>
                </list>
            </property>
        </bean>
    </mvc:interceptor>
</mvc:interceptors>

拦截器实现类如下

public class LoginInterceptor implements HandlerInterceptor {
    private AvatarLogger logger = AvatarLoggerFactory.getLogger(this.getClass());

    private List<String> excludedUrls;

    /**
     * 在DispatcherServlet完全处理完请求后被调用
     * 当拦截器抛出异常时,依然会从当前拦截器往回执行所的拦截器的afterCompletion()
     */
    public void afterCompletion(HttpServletRequest request,
                                HttpServletResponse response, Object handler, Exception exception)
            throws Exception {

    }

    //在业务处理器处理请求执行完成后,生成视图之前执行的动作
    public void postHandle(HttpServletRequest request, HttpServletResponse response,
                           Object handler, ModelAndView modelAndView) throws Exception {

    }

    /**
     * 在业务处理器处理请求之前被调用
     * 如果返回false 则退出本拦截器，本拦截器后面的postHandle与afterCompletion不再执行
     */
    public boolean preHandle(HttpServletRequest request, HttpServletResponse response,
                             Object handler) throws Exception {

        String requestUri = request.getRequestURI();
        for (String url : excludedUrls) {
            if (requestUri.contains(url)) {
                return true;
            }
        }

        HttpSession session = request.getSession();
        Boolean login = (Boolean) session.getAttribute("login");
        if (login == null || !login) {
            //System.out.println(request.getContextPath());
            logger.info("Pedirect to login page");
            response.sendRedirect(request.getContextPath() + "/login");
        }
        return true;
    }

    public void setExcludedUrls(List<String> excludedUrls) {
        this.excludedUrls = excludedUrls;
    }
}