Servlet课程0426（十二）Servlet MV模式下用户登录及查看用户表中所有用户
Welcome.java
//登录界面 package com.tsinghua; import javax.servlet.http.*; import java.io.*; import java.sql.*; import java.util.*; public class Welcome extends HttpServlet{ public void doGet(HttpServletRequest req, HttpServletResponse res) { //业务逻辑 Connection ct = null; PreparedStatement ps = null; ResultSet rs = null; try{ //从Session中得到用户名 HttpSession hs = req.getSession(true); String myName = (String)hs.getAttribute("uname"); String name=""; String passwd=""; if(myName == null) { //如果session中没有用户信息，在看看有没有cookie信息 //客户端得到所有cookie信息 Cookie[] allCookies = req.getCookies(); int i = 0; //如果allCookie不为空 if(allCookies != null) { //从中取出cookie for (i = 0; i<allCookies.length; i++) { //依次取出 Cookie temp = allCookies[i]; if(temp.getName().equals("myname")) { //得到cookie的值 name = temp.getValue(); } else if(temp.getName().equals("mypasswd")) { passwd = temp.getValue(); } } System.out.println("myname="+name+" passwd="+passwd); if(!name.equals("") && passwd.equals("")) { //loginCl去验证 res.sendRedirect("loginCl?username="+name+"&userpwd="+passwd); return; } } //返回登录界面 res.sendRedirect("login?info=error1"); return; } //解决中文乱码 res.setCharacterEncoding("gbk"); PrintWriter pw = res.getWriter(); pw.println("<html>"); pw.println("<body><center>"); //在Servlet中显示图片 pw.println("<img src='./imgs/1.GIF' /><br/>"); pw.println("wel,hello"); pw.println("你的用户名是,"+myName); pw.println("<br><a href=login>返回重新登录</a>"); //==========================分页的功能===================== int pageSize = 3;//一页显示几条记录 int pageNow = 1;//希望显示第几页 //动态的接收pageNow String sPageNow = req.getParameter("pageNow"); //用户第一次进入welcome页面，此时spageNow为null,所以不需要去改动pageNow，因为pageNow此时的值默认为1 if(sPageNow != null) { pageNow = Integer.parseInt(sPageNow); } //调用UserBeanCl UserBeanCl ubc = new UserBeanCl(); ArrayList al = ubc.getResultByPage(pageNow,pageSize); pw.println("<table border=1>"); pw.println("<tr><th>id</th><th>name</th><th>password</th><th>email</th><th>grade</th></tr>"); System.out.println("al.size = "+al.size()); for (int i = 0; i < al.size(); i++) { System.out.println("i = "+i); UserBean ub = (UserBean) al.get(i); pw.println("<tr>"); pw.println("<td>"+ub.getUserId()+"</td>"); pw.println("<td>"+ub.getUserName()+"</td>"); pw.println("<td>"+ub.getPasswd()+"</td>"); pw.println("<td>"+ub.getMail()+"</td>"); pw.println("<td>"+ub.getGrade()+"</td>"); pw.println("</tr>"); } pw.println("</table>"); //显示超链接 pw.println("<a href=wel?pageNow="+1+">首页</a>"); if(pageNow != 1) { pw.println("<a href=wel?pageNow="+(pageNow-1)+">上一页</a>"); } for(int i = pageNow; i <= pageNow+4; i++) { pw.println("<a href=wel?pageNow="+i+">"+i+"</a>"); } int pageCount = ubc.getPageCount(); if(pageNow != pageCount) { pw.println("<a href=wel?pageNow="+(pageNow+1)+">下一页</a>"); } pw.println("</center></body>"); pw.println("</html>"); } catch(Exception ex) { ex.printStackTrace(); } } //处理get请求 //req用于获得客户端(浏览器)的信息 //res用于向 客户端(浏览器)返回信息 public void doPost(HttpServletRequest req, HttpServletResponse res) { this.doGet(req,res); } }
UserBeanCl.java
//这是一个处理类(处理users表)<---->操作userBean //业务逻辑部分 package com.tsinghua; import java.sql.*; import java.util.*; public class UserBeanCl{ //业务逻辑 private Connection ct = null; private PreparedStatement ps = null; private ResultSet rs = null; private int pageCount = 0;//共有几页（计算出来的） //返回pageCount public int getPageCount() { return this.pageCount; } //分页显示 public ArrayList getResultByPage(int pageNow ,int pageSize){ ArrayList al = new ArrayList(); try{ int rowCount = 0;//共有几条记录(查表) //1加载驱动 ConnDB cd = new ConnDB(); ct = cd.getConn(); ps = ct.prepareStatement("select count(*) from users"); rs = ps.executeQuery(); if(rs.next()) { rowCount = rs.getInt(1); } //计算pageCount if(rowCount % pageSize == 0) { pageCount = rowCount/pageSize; } else { pageCount = rowCount/pageSize + 1; } ps = ct.prepareStatement("select top "+pageSize+" * from users where userId not in (select top "+(pageSize*(pageNow-1))+" userId from users)"); //执行查询 rs = ps.executeQuery(); while(rs.next()){ //将rs中的每条记录封装到userBean ub UserBean ub = new UserBean(); ub.setUserId(rs.getInt(1)); ub.setUserName(rs.getString(2)); ub.setPasswd(rs.getString(3)); ub.setMail(rs.getString(4)); ub.setGrade(rs.getInt(5)); //将ub放入到ArrayList中 al.add(ub); } }catch(Exception ex){ ex.printStackTrace(); }finally{ this.close(); } return al; } //验证用户 public boolean checkUser(String u, String p){ boolean b = false; try{ //得到连接 ConnDB cd = new ConnDB(); ct = cd.getConn(); ps = ct.prepareStatement("select top 1 passwd from users where username=?"); ps.setString(1,u); rs = ps.executeQuery(); if(rs.next()){ String dbPasswd = rs.getString(1); if(dbPasswd.equals(p)){ b = true; } } }catch(Exception ex){ ex.printStackTrace(); }finally{ this.close(); } return b; } //关闭资源 public void close() { try{ if(rs != null){ rs.close(); rs = null; } if(ps != null){ ps.close(); ps = null; } if(ct != null){ ct.close(); ct = null; } }catch(Exception ex){ ex.printStackTrace(); } } }
UserBean.java
//这是一个UserBean <---->user表映射 //它的一个对象<---->users表的一条记录对应 //本身代表的就是数据 package com.tsinghua; public class UserBean{ private int userId; private String userName; private String passwd; private String mail; private int grade; public void setUserId(int userId) { this.userId = userId; } public int getUserId() { return this.userId; } public void setUserName(String userName){ this.userName = userName; } public String getUserName(){ return this.userName; } public void setPasswd(String passwd) { this.passwd = passwd; } public String getPasswd(){ return this.passwd; } public void setMail(String mail) { this.mail = mail; } public String getMail(){ return this.mail; } public void setGrade(int grade) { this.grade = grade; } public int getGrade() { return this.grade; } }
ConnDB.java
//从数据库中得到连接 package com.tsinghua; import java.sql.*; public class ConnDB{ private Connection ct = null; public Connection getConn() { try{ //1.加载 驱动 Class.forName("com.microsoft.sqlserver.jdbc.SQLServerDriver"); //2.返回连接 ct = DriverManager.getConnection("jdbc:sqlserver://127.0.0.1:1433;databaseName=spdb","sa","123456"); }catch(Exception ex){ ex.printStackTrace(); } return ct; } }
LoginCl.java
//登录界面 package com.tsinghua; import javax.servlet.http.*; import java.io.*; import java.sql.*; public class LoginCl extends HttpServlet{ public void doGet(HttpServletRequest req, HttpServletResponse res) { Connection ct = null; Statement sm = null; ResultSet rs = null; //业务逻辑 try{ //接收用户名和密码 String u = req.getParameter("username"); String p = req.getParameter("userpwd"); //调用UserBeanCl 1.创建一个对象 UserBeanCl ubc = new UserBeanCl(); //2.使用UserBeanCl处理的方法 if(ubc.checkUser(u,p)) { //将用户名和密码保存在客户端 //创建Cookie Cookie name = new Cookie("myname",u); Cookie pass = new Cookie("mypasswd",p); //设置时间 name.setMaxAge(14*24*3600); pass.setMaxAge(14*24*3600); //回写到客户端 res.addCookie(name); res.addCookie(pass); //将验证成功的信息写入session //得到session,得到session那张表 HttpSession hs = req.getSession(true); //默认30分钟，为了展示效果下面修改销毁时间 //该方法是按照秒来算的 hs.setMaxInactiveInterval(30); //写入属性 hs.setAttribute("uname",u); //跳转到welcome res.sendRedirect("wel?uname="+u); }else{ //说明用户名不存在 //不合法 //写你要到的Servlet的那个URL res.sendRedirect("login"); } } catch(Exception ex) { ex.printStackTrace(); }finally{ try{ if(rs != null) rs.close(); if(sm != null) sm.close(); if(ct != null) ct.close(); }catch(Exception ex){ ex.printStackTrace(); } } } //处理get请求 //req用于获得客户端(浏览器)的信息 //res用于向 客户端(浏览器)返回信息 public void doPost(HttpServletRequest req, HttpServletResponse res) { this.doGet(req,res); } }
Login.java
//登录界面 package com.tsinghua; import javax.servlet.http.*; import java.io.*; public class Login extends HttpServlet{ public void doGet(HttpServletRequest req, HttpServletResponse res) { //业务逻辑 try{ //中文乱码 //浏览器默认ISO-8859 res.setContentType("text/html;charset=gbk"); PrintWriter pw = res.getWriter(); //返回登录界面 pw.println("<html>"); pw.println("<body>"); //得到error信息 String info = req.getParameter("info"); if(info != null) { pw.println("<h1>你的用户名或是密码错误！</h1>"); } pw.println("<h1>登录界面</h1>"); pw.println("<form action='loginCl' method=post>"); pw.println("用户名<input type='text' name='username'/><br/>"); pw.println("<br/>密 码<input type='password' name='userpwd'/><br/>"); pw.println("<br/><input type=checkbox name=keep value=2/>两周内不用再登录<br/>"); pw.println("<br/><input type='submit' value='loing' /><br/>"); pw.println("</form>"); pw.println("</body>"); pw.println("</html>"); } catch(Exception ex) { ex.printStackTrace(); } } //处理get请求 //req用于获得客户端(浏览器)的信息 //res用于向 客户端(浏览器)返回信息 public void doPost(HttpServletRequest req, HttpServletResponse res) { this.doGet(req,res); } }
