码农的希望
回复 想要飞的更高：RBAC 基于角色的权限控制 tb_user tb_role tb_userrole tb_menu(增、删、改、查) tb_rolemenu1 说明我们给出三个页面：index.jsp、user.jsp、admin.jsp。 index.jsp：谁都可以访问，没有限制； user.jsp：只有登录用户才能访问； admin.jsp：只有管理员才能访问。2 分析设计User类：username、password、grade，其中grade表示用户等级，1表示普通用户，2表示管理员用户。当用户登录成功后，把user保存到session中。创建LoginFilter，它有两种过滤方式： 如果访问的是user.jsp，查看session中是否存在user； 如果访问的是admin.jsp，查看session中是否存在user，并且user的grade等于2。3 代码User.javapublic class User { private String username; private String password; private int grade;…}为了方便，这里就不使用数据库了，所以我们需要在UserService中创建一个Map，用来保存所有用户。Map中的key中用户名，value为User对象。UserService.javapublic class UserService { private static Map<String,User> users = new HashMap<String,User>(); static { users.put("zhangSan", new User("zhangSan", "123", 1)); users.put("liSi", new User("liSi", "123", 2)); } public User login(String username, String password) { User user = users.get(username); if(user == null) return null; return user.getPassword().equals(password) ? user : null; }}login.jsp <body> <h1>登录</h1> <p style="font-weight: 900; color: red">${msg }</p> <form action="<c:url value='/LoginServlet'/>" method="post"> 用户名：<input type="text" name="username"/><br/> 密 码：<input type="password" name="password"/><br/> <input type="submit" value="登录"/> </form> </body>index.jsp <body> <h1>主页</h1> <h3>${user.username }</h3> <hr/> <a href="<c:url value='/login.jsp'/>">登录</a><br/> <a href="<c:url value='/user/user.jsp'/>">用户页面</a><br/> <a href="<c:url value='/admin/admin.jsp'/>">管理员页面</a> </body>/user/user.jsp<body><h1>用户页面</h1><h3>${user.username }</h3><hr/></body>/admin/admin.jsp<body> <h1>管理员页面</h1> <h3>${user.username }</h3> <hr/></body>LoginServletpublic class LoginServlet extends HttpServlet { public void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException { request.setCharacterEncoding("utf-8"); response.setContentType("text/html;charset=utf-8"); String username = request.getParameter("username"); String password = request.getParameter("password"); UserService userService = new UserService(); User user = userService.login(username, password); if(user == null) { request.setAttribute("msg", "用户名或密码错误"); request.getRequestDispatcher("/login.jsp").forward(request, response); } else { request.getSession().setAttribute("user", user); request.getRequestDispatcher("/index.jsp").forward(request, response); } }}LoginUserFilter.java <filter> <display-name>LoginUserFilter</display-name> <filter-name>LoginUserFilter</filter-name> <filter-class>cn.itcast.filter.LoginUserFilter</filter-class> </filter> <filter-mapping> <filter-name>LoginUserFilter</filter-name> <url-pattern>/user/*</url-pattern> </filter-mapping>public class LoginUserFilter implements Filter { public void destroy() {} public void init(FilterConfig fConfig) throws ServletException {} public void doFilter(ServletRequest request, ServletResponse response, FilterChain chain) throws IOException, ServletException { response.setContentType("text/html;charset=utf-8"); HttpServletRequest req = (HttpServletRequest) request; User user = (User) req.getSession().getAttribute("user"); if(user == null) { response.getWriter().print("您还没有登录"); return; } chain.doFilter(request, response); }}LoginAdminFilter.java <filter> <display-name>LoginAdminFilter</display-name> <filter-name>LoginAdminFilter</filter-name> <filter-class>cn.itcast.filter.LoginAdminFilter</filter-class> </filter> <filter-mapping> <filter-name>LoginAdminFilter</filter-name> <url-pattern>/admin/*</url-pattern> </filter-mapping>public class LoginAdminFilter implements Filter { public void destroy() {} public void init(FilterConfig fConfig) throws ServletException {} public void doFilter(ServletRequest request, ServletResponse response, FilterChain chain) throws IOException, ServletException { response.setContentType("text/html;charset=utf-8"); HttpServletRequest req = (HttpServletRequest) request; User user = (User) req.getSession().getAttribute("user"); if(user == null) { response.getWriter().print("您还没有登录!"); return; } if(user.getGrade() < 2) { response.getWriter().print("您的等级不够！"); return; } chain.doFilter(request, response); }}