登陆session案例的经典实现.doc

Login.jspLogin.htmlLoginNamePasswordCheckLogin.javapackage com;import java.io.IOException;import java.io.PrintWriter;import javax.servlet.RequestDispatcher;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.hnsfxy.dao.IAdminDao;import com.hnsfxy.dao.impl.AdminDaoImpl;public class CheckLogin extends HttpServlet public void doGet(HttpServletRequest request, HttpServletResponse response)throws ServletException, IOException / 编码问题response.setContentType(text/html;charset=GBK);/ 浏览器显示的编码，默认的是isoresponse.setCharacterEncoding(GBK);/ 浏览器到数据库取数据时候使用的编码request.setCharacterEncoding(GBK);/ 浏览器到数据库存入数据时候所使用的编码方式/ 2首先在一個servlet中通过request获得session对象（可以是来自html的请求）sessionHttpSession session = request.getSession();/ 3设置session超时间隔为60秒sessionsession.setMaxInactiveInterval(60);/ 获取表单的值/不要.trim（）String name = request.getParameter(user).trim();在IE中输入check时候，会出现NullPointException/以下部分如果name为空或者在IE中输入check的时候会跳转到Login.jsp中去String name = request.getParameter(user);String password = request.getParameter(pwd);if (name = null | name.trim().equals() | password = null| password.equals() / 跳转回去RequestDispatcher rd = request.getRequestDispatcher(./Login.jsp);rd.forward(request, response);/ 跳到登陆页面 else / 调用dao层的方法进行判断IAdminDao admin = new AdminDaoImpl();if (admin.checkLogin(name, password) = 0) /成功登陆/否则将name password加入到session中去session.setAttribute(name, name);/ 把输入的用户名添加到session中session.setAttribute(pwd, password);/ 把输入的用户名添加到session中response.sendRedirect(/Login/selectAll); else if (admin.checkLogin(name, password) = 1) / request.setAttribute(error,密码错误！);response.sendRedirect(./Login.jsp); else if(admin.checkLogin(name, password) = 2) / request.setAttribute(2,用户不存在，请先注册！);response.sendRedirect(./Login.jsp);public void doPost(HttpServletRequest request, HttpServletResponse response)throws ServletException, IOException doGet(request, response);SelAll.javapackage com;import java.io.IOException;import java.io.PrintWriter;import java.util.ArrayList;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.hnsfxy.dao.IPersonDao;import com.hnsfxy.dao.impl.PersonDaoImpl;import com.hnsfxy.entity.Person;public class SelAll extends HttpServlet public void doGet(HttpServletRequest request, HttpServletResponse response)throws ServletException, IOException / 编码问题response.setContentType(text/html;charset=GBK);/ 浏览器显示的编码，默认的是isoresponse.setCharacterEncoding(GBK);/ 浏览器到数据库取数据时候使用的编码request.setCharacterEncoding(GBK);/ 浏览器到数据库存入数据时候所使用的编码方式PrintWriter out = response.getWriter();/ 1 不同的请求在同一個session对象中传值 创建session对象（通过request）HttpSession session = request.getSession();/ 2 获取另外一个servlet中的session的值String sessionName = (String) session.getAttribute(name);String sessionPwd = (String) session.getAttribute(pwd);if (null = sessionName | .equals(sessionName) | null = sessionPwd| .equals(sessionPwd) response.sendRedirect(./Login.jsp);/ 跳到登陆页面return;List list = new ArrayList();IPersonDao person = new PersonDaoImpl();list = person.selAllPerson();request.setAttribute(list,list);request.getRequestDispatcher(./SelAll.jsp).forward(request, response);public void doPost(HttpServletRequest request, HttpServletResponse response)throws ServletException, IOException doGet(request, response);SelAll.jspJsp+Servlet+DaoJSP查询所有的记录用户