session的权限判断

1.session判断用户存不存在

package com.pw.web.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 com.pw.po.User;public class QFilter implements Filter {public void init(FilterConfig filterConfig) throws ServletException {// TODO Auto-generated method stub}public void doFilter(ServletRequest request, ServletResponse response,FilterChain chain) throws IOException, ServletException {HttpServletRequest request2= (HttpServletRequest)request;    HttpServletResponse response2=(HttpServletResponse)response;    HttpSession session=request2.getSession();    User user=(User)session.getAttribute("loginUser");    System.out.println("*******");    String s=request2.getRequestURI();    int index=s.indexOf("1");    String path=s.substring(index+1);    System.out.println(path);        if(user!=null ||"/LoginServlet".equals(path)){    chain.doFilter(request2, response2);    }else{    request2.getRequestDispatcher("/login.jsp").forward(request2, response2);        }}public void destroy() {}}

2servlet部分：

package com.pw.web.servlet;import java.io.IOException;import java.io.PrintWriter;import java.util.List;import javax.servlet.ServletException;import javax.servlet.http.HttpServlet;import javax.servlet.http.HttpServletRequest;import javax.servlet.http.HttpServletResponse;import javax.servlet.http.HttpSession;import com.pw.dao.Userdao;import com.pw.po.User;public class LoginServlet extends HttpServlet {@Overrideprotected void service(HttpServletRequest req, HttpServletResponse resp)throws ServletException, IOException {resp.setContentType("text/html;charset=utf-8");String qq=req.getParameter("qq");String pass=req.getParameter("pwd");Userdao dao = new Userdao();System.out.println("*******");User u1=dao.getUserByName(qq);HttpSession session=req.getSession();session.setAttribute("loginUser", u1);List<User> users=dao.getUserAll();System.out.println(u1+"ui");if(u1!=null){System.out.println(u1);if(u1.getPassword().equals(pass)){req.setAttribute("users", users);//req.setAttribute("us", u1);//req.setAttribute("user", qq);req.getRequestDispatcher("/success.jsp").forward(req, resp);//resp.sendRedirect("/servlet01/success.jsp");//跳转区别//req.getRequestDispatcher("/http://www.baidu.com").forward(req, resp);//resp.sendRedirect("http://www.baidu.com");return;}else{req.getRequestDispatcher("/fail.jsp").forward(req, resp);return;}}resp.setContentType("text/html;charset=utf-8");PrintWriter out =resp.getWriter();out.print("dsadsa");out.print("<p style='color:red'>sdasasda</p>");out.flush();out.close();System.out.println(qq+"****"+pass);//System.out.println("***********************************");//System.out.println(req.getMethod());//System.out.println(req.getContextPath());//System.out.println(req.getRequestURL());//System.out.println(req.getAuthType()+"auth");//System.out.println(req.getContentLength()+"conlenth");//System.out.println(req.getLocalAddr()+"addr");//System.out.println(req.getLocalPort()+"port");//System.out.println(req.getPathInfo()+"info");//System.out.println(req.getCharacterEncoding()+"CharacterEncoding");}}