Java 对全局用户是否登录验证

在web.xml配置filter

 

<!-- 登录认证过滤器 -->
<filter>
<filter-name>UserFilter</filter-name>
<filter-class>com.filter.UserFilter</filter-class>
</filter>
<filter-mapping>
<filter-name>UserFilter</filter-name>
<url-pattern>*.jsp</url-pattern>
</filter-mapping>
<filter-mapping>
<filter-name>UserFilter</filter-name>
<url-pattern>*.action</url-pattern>
</filter-mapping>

后台class

 

public class UserFilter implements Filter{

    @Override
    public void destroy() {
        
    }

    @Override
    public void doFilter(ServletRequest request, ServletResponse response,
            FilterChain chain) throws IOException, ServletException {
        HttpServletResponse resp = (HttpServletResponse)response;
        HttpServletRequest req = (HttpServletRequest)request;
        HttpSession session = req.getSession();
        User user = (User)session.getAttribute("user");
        String uri = req.getRequestURI();
        //简单判断缓存中是否有用户
        if(user==null){//没有用户
            //判断用户是否是选择跳到登录界面
            if(uri.endsWith("login.jsp")||uri.endsWith("login.do")){
                chain.doFilter(request, response);
            }else{
                resp.sendRedirect(req.getContextPath()+"/login.jsp");
            }    
        }else{//有用户
            chain.doFilter(request, response);
        }
        chain.doFilter(request, response);
    }

    @Override
    public void init(FilterConfig filterConfig) throws ServletException {
        
    }

}

首先要在登录时把user存到session中