攔截器 Filter ： js、css、jpg、png等靜態資源不被攔截解決方案

方案一：

web.xml配置文件攔截范圍縮小 ，沒有必要 /*的配置攔截項目下所有資源。

<filter>
        <filter-name>Login</filter-name>
        <filter-class>com.ssm.crm.filter.LoginFilter</filter-class>
    </filter>
    <filter-mapping>
        <filter-name>Login</filter-name>
        <url-pattern>/*</url-pattern>
    </filter-mapping>

修改如下：

    <filter>
        <filter-name>Login</filter-name>
        <filter-class>com.ssm.crm.filter.LoginFilter</filter-class>
    </filter>
    <filter-mapping>
        <filter-name>Login</filter-name>
        <url-pattern>*.action</url-pattern>
    </filter-mapping>
    <filter-mapping>
        <filter-name>Login</filter-name>
        <url-pattern>*.do</url-pattern>
    </filter-mapping>
    <filter-mapping>
        <filter-name>Login</filter-name>
        <url-pattern>*.jsp</url-pattern>
    </filter-mapping>

進一步優化 ：把所有的頁面無需攔截的文件（jsp，html，ftl，css等放在同一個文件夾下；需要攔截的請求公有路徑也統一）攔截是配置為：

<filter-mapping>
        <filter-name>Login</filter-name>
        <url-pattern>/文件夾名字/*</url-pattern>
    </filter-mapping>
    <filter-mapping>
        <filter-name>Login</filter-name>
        <url-pattern>/需要攔截的請求公有路徑/*</url-pattern>
    </filter-mapping>

方案二：

過濾掉js，css等相關文件

public void doFilter(ServletRequest request, ServletResponse response, FilterChain chain) throws IOException, ServletException {
        HttpServletRequest req = (HttpServletRequest)request;
        HttpServletResponse res = (HttpServletResponse)response;
        HttpSession session = req.getSession();
        LoginUser loginUser = (LoginUser) session.getAttribute("loginUser");
        String spath = req.getServletPath();
    System.out.println("request.getContextPath()"+req.getContextPath());
        //不需要過濾的url
        String[] urls = {"/login","/json",".js",".css",".ico",".jpg",".png"};
        boolean flag = true;
        for (String str : urls) {
            if (spath.indexOf(str) != -1) {
                flag =false;
                break;
            }
        }
        if (flag) {
            if (loginUser != null) {
                chain.doFilter(request, response);
            }else {
                res.sendRedirect(req.getContextPath()+"/webpage/page/login/login.jsp");
            }
        }else{
            chain.doFilter(request, response);  
       }

    }