Servlet拦截器

1.LoginFilter

package main.java.filter;import javax.servlet.*;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import javax.servlet.http.HttpSession;
import java.io.IOException;public class LoginFilter implements Filter {@Overridepublic void init(FilterConfig filterConfig) {}/*** @description 登录拦截* @param servletRequest 请求* @param servletResponse 响应* @param filterChain 持有Filter列表的管理和控制* @author zhq* @throws IOException 读写异常* @throws ServletException Servlet异常* @date 2021/5/24 10:40* @version 1.0*/@Overridepublic void doFilter(ServletRequest servletRequest, ServletResponse servletResponse, FilterChain filterChain) throws IOException, ServletException {HttpServletRequest request = (HttpServletRequest) servletRequest;HttpServletResponse response = (HttpServletResponse) servletResponse;HttpSession session = request.getSession();Object username = session.getAttribute("username");String path = request.getServletPath();//不需要过滤的urlString[] urls = {"/login","/json",".js",".css",".ico",".jpg",".png"};// flag是登录成功标志boolean flag = true;for (String url : urls) {if (path.contains(url) && !path.contains(".jsp")){flag = false;break;}else if (path.contains("login.jsp")){flag = false;break;}}if (flag) {if (username != null) {filterChain.doFilter(request, response);}else {response.sendRedirect("login.jsp");}}else{filterChain.doFilter(request, response);}}@Overridepublic void destroy() {}
}

2.web.xml配置

<filter><filter-name>LoginFilter</filter-name><filter-class>main.java.filter.LoginFilter</filter-class></filter><filter-mapping><filter-name>LoginFilter</filter-name><url-pattern>/*</url-pattern></filter-mapping>