java filter - Java / Web 开发

要使用 java filter 过滤用户的非常请求页面，如果没有登录那就显示主页。
  用struts2 来控制跳转
  java filter 配置
Java code:

<filter>
<filter-name>filter</filter-name>
<filter-class>com.aps.comm.filter.LoginFilter</filter-class>
</filter>

<filter-mapping>
<filter-name>filter</filter-name>
<url-pattern>*.jsp</url-pattern>
</filter-mapping>

<filter-mapping>
<filter-name>filter</filter-name>
<url-pattern>*.action</url-pattern>
</filter-mapping>



doFilter 
Java code:

HttpServletRequest httpRequest = (HttpServletRequest) request;
HttpServletResponse httpResponse = (HttpServletResponse) response;

String user= (String)httpRequest.getSession().getAttribute("user");

System.out.println("user"+user);

if (null == user || "".equals(user))
{
httpResponse.sendRedirect("/aps/index.jsp");