过滤器配置

       web.xml 配置 

       <filter>

　 <filter-name>loginFilter</filter-name>
<filter-class>com.baidu.dianquan.cashier.filter.LoginFilter</filter-class>
</filter>
<filter-mapping>
<filter-name>loginFilter</filter-name>
<url-pattern>/page/*</url-pattern>

</filter-mapping>

类：

public class LoginFilter  implements Filter{


@Override
public void destroy() {
// TODO Auto-generated method stub

}


@Override
public void doFilter(ServletRequest request, ServletResponse response,
  FilterChain filter) throws IOException, ServletException {
HttpServletRequest request2 = (HttpServletRequest)request;
HttpServletResponse response2 = (HttpServletResponse)response;
HttpSession Session = request2.getSession();
String name = (String)Session.getAttribute("name");
if(null==name){
response2.sendRedirect(request2.getContextPath() + "/login.jsp");
}else{
filter.doFilter(request, response);
}
}


@Override
public void init(FilterConfig arg0) throws ServletException {

}


}