filter_权限过滤器

package org.filter; import java.io.IOException; import javax.servlet.Filter; import javax.servlet.FilterChain; import javax.servlet.FilterConfig; import javax.servlet.ServletException; import javax.servlet.ServletRequest; import javax.servlet.ServletResponse; import javax.servlet.http.HttpServletRequest; import javax.servlet.http.HttpServletResponse; import javax.servlet.http.HttpSession; import org.vo.Users; public class LoginFilter implements Filter { private static final String PARAM_PWD = "pwd"; //request发来的参数 private static final String PARAM_UID = "uid"; private static final String USER_INFO = "userInfo"; //session中保存用户时,作键 private static final String MSG = "msg"; //request中保存提示信息时,作键 private static final String MSG_NOTLOGIN = "您尚未登录"; //值 private static final String MSG_BADLOGIN = "用户名或密码出错"; private static final String JSP_MAIN = "main.jsp"; //主界面 private static final String JSP_LOGIN = "login.jsp"; //登录页 public void doFilter(ServletRequest arg0, ServletResponse arg1, FilterChain arg2) throws IOException, ServletException { HttpServletRequest request = (HttpServletRequest) arg0; HttpServletResponse response = (HttpServletResponse) arg1; HttpSession session = request.getSession(); /* 1.已登录,则可以到任何页面 2.未登录 2.1 访问主界面.[重点] 2.2 访问其它界面.提示未登录,重定向到登录页 */ boolean bool = session.getAttribute(USER_INFO) != null; if (bool) { //1 arg2.doFilter(arg0, arg1); } else { //2.1 if (request.getRequestURI().indexOf(JSP_MAIN) != -1){ boolean b = login(request, response); if (b){ request.getRequestDispatcher(JSP_MAIN).forward(request, response); return;//这个return必须写上 } else { request.getRequestDispatcher(JSP_LOGIN).forward(request, response); return;//这个return必须写上 } //2.2 } else { request.setAttribute(MSG, MSG_NOTLOGIN); request.getRequestDispatcher(JSP_LOGIN).forward(arg0, arg1); } } } /** * 访问主页面 * @param request * @param response * @return */ private boolean login(HttpServletRequest request, HttpServletResponse response){ String uid = request.getParameter(PARAM_UID); String pwd = request.getParameter(PARAM_PWD); //直接访问主界面,视为未登录 if (uid==null || pwd==null || uid.equals("") || pwd.equals("")){ request.setAttribute(MSG, MSG_NOTLOGIN); return false; } /* 1.登录成功 session中保存用户身份 [key:USER_INFO, value:u] 2.登录失败 request中保存提示信息 [key:msg, value:用户名或者密码出错] */ boolean b = uid.equals(pwd); if(b) { //1 HttpSession session = request.getSession(); Users u = new Users(uid); session.setAttribute(USER_INFO, u); return true; }else{ //2 request.setAttribute(MSG, MSG_BADLOGIN); return false; } } public void init(FilterConfig filterConfig) throws ServletException { } public void destroy() { } }