Filter案例-登录验证的实现
Filter案例-登录验证的实现
需求:访问服务器资源时,需要先进行登录验证,如果没有登录,则自动跳转到登录页面
/**
* 登录验证的过滤器
*/
@WebFilter("/*")
public class LoginFilter implements Filter {
public void init(FilterConfig config) throws ServletException {
}
public void destroy() {
}
@Override
public void doFilter(ServletRequest request, ServletResponse response, FilterChain chain) throws ServletException, IOException {
HttpServletRequest req = (HttpServletRequest) request;
// 判断访问资源路径是否和登录注册相关
String[] urls = {"/login.jsp", "/imgs/", "/css", "/loginServlet", "/register.jsp", "/registerServlet", "checkCodeServlet"};
// 获取当前访问的资源路径
String url = req.getRequestURL().toString();
for (String u : urls) {
if (url.contains(u)){
// 找到了
// 放行
chain.doFilter(request, response);
return;
}
}
// 1. 判断session中是否有user
HttpSession session = req.getSession();
Object user = session.getAttribute("user");
// 2. 判断user是否为null
if (user != null){
// 登录过了
// 放行
chain.doFilter(request, response);
}else{
// 没有登录,存储提示信息,跳转到登录页面
req.setAttribute("login_msg", "您尚未登录!");
req.getRequestDispatcher("/login.jsp").forward(req, response);
}
}
}