JSF中Filter的实现

大概思路是 建一个filter  过滤除登陆页面的其他所有页面  在filter 里取到session 判断里面是否有值 如果有 则正常跳转  否则跳转到登陆页或你需要的指定页面即可~代码如下：

 

在web.xml里面加上filter ：

<!-- 用户登录过滤器开始 -->

<!-- 用户登录过滤器开始 --> 
<filter> 
<filter-name>checkLoginFilter </filter-name> 
<filter-class>CheckLoginFilter </filter-class> 
<init-param> 
<param-name>checkSessionKey </param-name> 
<param-value>LoginUser </param-value> 
</init-param> 
<init-param> 
<param-name>redirectURL </param-name> 
<param-value>/login.jsf </param-value> 
</init-param> 
<init-param> 
<param-name>notCheckURLList </param-name> 
<param-value>/login.jsf </param-value> 
</init-param> 
</filter> 
<filter-mapping> 
<filter-name>checkLoginFilter </filter-name> 
<url-pattern>*.jsf </url-pattern> 
</filter-mapping> 

<!-- 用户登录过滤器结束 -->

/** 
* 用于检测用户是否登陆的过滤器，如果未登录，则重定向到指的登录页面 <p> 
* 配置参数 <p> 
* checkSessionKey 需检查的在 Session 中保存的关键字 <br/> 
* redirectURL 如果用户未登录，则重定向到指定的页面，URL不包括 ContextPath <br/> 
* notCheckURLList 不做检查的URL列表，以分号分开，并且 URL 中不包括 ContextPath <br/> 
*/ 
public class CheckLoginFilter implements Filter 
{ 
    protected FilterConfig filterConfig = null; 
    private String redirectURL = null; 
    private List <String> notCheckURLList = new ArrayList <String>(); 
    private String sessionKey = null; 

    public void doFilter(ServletRequest servletRequest, ServletResponse servletResponse, FilterChain filterChain) throws IOException, ServletException{ 
    
    HttpServletRequest request = (HttpServletRequest) servletRequest; 
    HttpServletResponse response = (HttpServletResponse) servletResponse; 
    HttpSession session = request.getSession(); 
    response.setHeader("Cache-Control","no-cache"); 
    response.setHeader("Pragma","no-cache"); 
    response.setDateHeader ("Expires", -1); 
    if(sessionKey == null){ 
    filterChain.doFilter(request, response); 
    return; 
    } 
    if((!checkRequestURIIntNotFilterList(request)) && session.getAttribute(sessionKey) == null){ 
    response.sendRedirect(request.getContextPath() + redirectURL); 
    return; 
    } 
    filterChain.doFilter(servletRequest, servletResponse); 
    } 

    public void destroy(){ 
    notCheckURLList.clear(); 
    } 

    private boolean checkRequestURIIntNotFilterList(HttpServletRequest request){ 
    String uri = request.getServletPath() + (request.getPathInfo() == null ? "" : request.getPathInfo()); 
    return notCheckURLList.contains(uri); 
    } 

    public void init(FilterConfig filterConfig) throws ServletException{ 
    this.filterConfig = filterConfig; 
    redirectURL = filterConfig.getInitParameter("redirectURL"); 
    sessionKey = filterConfig.getInitParameter("checkSessionKey"); 

    String notCheckURLListStr = filterConfig.getInitParameter("notCheckURLList"); 

    if(notCheckURLListStr != null){ 
    StringTokenizer st = new StringTokenizer(notCheckURLListStr, ";"); 
    notCheckURLList.clear(); 
    while(st.hasMoreTokens()){ 
    notCheckURLList.add(st.nextToken()); 
    } 
    } 
    } 
}

此方法不足之处在于jsf的filter生命周期在jsf之前，登录页面的标签样式无法正常显示