javaweb实现的访问权限控制示例

package filter; import javax.servlet.*; import javax.servlet.annotation.WebFilter; import javax.servlet.http.Cookie; import javax.servlet.http.HttpServletRequest; import javax.servlet.http.HttpServletResponse; import java.io.IOException; @WebFilter(filterName = "LoginFilter", urlPatterns = "*.jsp", dispatcherTypes = {}) public class LoginFilter implements Filter { public void destroy() { } public void doFilter(ServletRequest req, ServletResponse resp, FilterChain chain) throws ServletException, IOException { System.out.println("LoginFilter doFilter"); HttpServletRequest request = (HttpServletRequest) req; HttpServletResponse response = (HttpServletResponse) resp; String url = request.getRequestURI(); System.out.println("请求的url：" + url); /*登录页面不需要过滤*/ int idx = url.lastIndexOf("/"); String endWith = url.substring(idx + 1); if (!endWith.equals("login.jsp")) { /*不是登录页面 进行拦截处理*/ System.out.println("不是登录页面，进行拦截处理"); if (!isLogin(request)) { System.out.println("没有登录过或者账号密码错误，跳转到登录界面"); response.sendRedirect("login.jsp"); } else { System.out.println("已经登录，进行下一步"); chain.doFilter(req, resp); } } else { System.out.println("是登录页面，不进行拦截处理"); chain.doFilter(req, resp); } } private boolean isLogin(HttpServletRequest request) { Cookie[] cookies = request.getCookies(); String account = ""; String pwd = ""; if (cookies != null && cookies.length > 0) { for (Cookie cookie : cookies) { if (cookie.getName().equals("account")) { account = cookie.getValue(); } else if (cookie.getName().equals("pwd")) { pwd = cookie.getValue(); } } } if (account.equals("") || pwd.equals("")) { return false; } else if (account.equals("yzq") && pwd.equals("123")) { return true; } return false; } public void init(FilterConfig config) throws ServletException { System.out.println("LoginFilter init"); } }