用户登录网站（servlet版本1.2）

来源：互联网发布：totalfinder for mac 编辑：程序博客网时间：2024/04/29 09:18

一、视图层

LoginCl.java(验证用户)

Wel.java(欢迎界面)

二、模型层

ConnDB.java(数据库连接)

UserBean.java(表示users表)

UserBeanCl.java(业务逻辑控制)

三、注意：

1.部署web.xml

2.添加mysql数据库

create database spdb;use spdb;create table users(userId int auto_increment primary key not null, username varchar(20), passwd varchar(30), email varchar(30), grade int );

四、参考代码如下：

视图层

package com.tsinghua;import javax.servlet.*;import javax.servlet.http.*;import java.io.*;public class Login extends HttpServlet {public Login(){super();}public void init() throws ServletException{}public void process(HttpServletRequest req,HttpServletResponse res) throws ServletException,IOException{try{ //中文乱码解决 res.setContentType("text/html;charset=UTF-8"); //业务逻辑 PrintWriter pw=res.getWriter(); //返回登录界面 pw.println("<html>"); pw.println("<body>"); //得到erro信息 String info=(String)req.getParameter("info"); if(info!=null){ pw.println("<h1>你的用户名或是密码错误！</h1><br>"); } 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("密码：<input type=password name=passwd><br>"); pw.println("<input type=checkbox name=keep value=2>两周内不用重新登录<br>"); pw.println("<input type=submit value=loging><br>"); pw.println("</form>"); pw.println("</body>"); pw.println("</html>");}catch(Exception ex){ex.printStackTrace();}}public void doGet(HttpServletRequest req,HttpServletResponse res) throws ServletException,IOException{process(req,res);}public void doPost(HttpServletRequest req,HttpServletResponse res) throws ServletException,IOException{process(req,res);}public void destroy(){super.destroy();}}

LoginCl.java(验证用户)

package com.tsinghua;import javax.servlet.*;import javax.servlet.http.*;import java.io.*;import java.sql.*;public class LoginCl extends HttpServlet {public LoginCl() {super();}public void init() throws ServletException {}// req:用于获得浏览器的信息// res:用于向浏览器返回信息（我就是服务器）public void process(HttpServletRequest req, HttpServletResponse res)throws ServletException, IOException {res.setContentType("text/html;charset=UTF-8");// 处理中文乱码try {// 接收用户名和密码String u = req.getParameter("username");String p = req.getParameter("passwd");System.out.println("创建一个对象");//调用UserBeanCl，1.创建一个对象UserBeanCl ubc=new UserBeanCl();//2.使用UserBeanCl的方法if (ubc.checkUser(u, p)) {// 合法用户String keep = req.getParameter("keep");if (keep != null) {// 将用户名和密码保存在客户端（cookie）// 创建Cookie name = new Cookie("myname", u);Cookie pass = new Cookie("mypasswd", p);// 设置时间name.setMaxAge(14 * 24 * 3600);name.setMaxAge(14 * 24 * 3600);// 回写到客户端res.addCookie(name);res.addCookie(pass);}// 将用户信息存入session中HttpSession hs = req.getSession(true);hs.setMaxInactiveInterval(30);hs.setAttribute("name", u);res.sendRedirect("welcome");// 跳转} else {//不合法用户System.out.println("用户或密码错了");res.sendRedirect("login");}} catch (Exception ex) {ex.printStackTrace();} }public void doGet(HttpServletRequest req, HttpServletResponse res)throws ServletException, IOException {process(req, res);}public void doPost(HttpServletRequest req, HttpServletResponse res)throws ServletException, IOException {process(req, res);}public void destroy() {}}

Wel.java(欢迎界面)

package com.tsinghua;import java.io.*;import java.sql.*;import java.util.*;import javax.servlet.*;import javax.servlet.http.*;public class Wel extends HttpServlet {public Wel() {super();}public void init() throws ServletException {}public void process(HttpServletRequest req, HttpServletResponse res)throws ServletException, IOException {res.setContentType("text/html;charset=UTF-8");PrintWriter pw = res.getWriter();try {// 从session中得到用户名HttpSession hs = req.getSession(true);String myName = (String) hs.getAttribute("name");String name="";String passwd="";if (myName == null) {// 如果session中没有用户信息，再看看有没有cookie信息// 从客户端得到所有的cookie信息Cookie[] allCookies = req.getCookies();int i = 0;// 如果allCookies不为空if (allCookies != null) {for (i = 0; i < allCookies.length; i++) {// 从中取出cookie// 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();}}if(!name.equals("")&&!passwd.equals("")){//到LoginCl.java去验证res.sendRedirect("logincl?username="+name+"&passwd="+passwd);return;}}// 返回登陆界面res.sendRedirect("login?info=error1");return;}// 调整格式pw.println("<body><center>");// 在servlet中显示图片pw.println("<img src="images/lola.gif" mce_src="images/lola.gif"><br>");pw.println("Welcom,hello<br>");pw.println("你的用户名是：" + myName);// 做个超链接pw.println("<br><a href="login" mce_href="login">返回重新登录</a>");// ================分页功能===============int pageSize = 3;// 一页显示几条记录（规定）int pageNow = 1;// 希望显示第几页（规定）// 动态的接收pageNowString sPageNow = req.getParameter("pageNow");if (sPageNow != null) {pageNow = Integer.parseInt(sPageNow);// 转换成整数} //调用userBeanClUserBeanCl ubc=new UserBeanCl();ArrayList al=ubc.getResultByPage(pageNow, pageSize);// 表头pw.println("<table border=1>");pw.println("<tr><th>id</th><th>name</th><th>passwd</th><th>email</th><th>grade</th></tr>");for(int i=0;i<al.size();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.getEmail() + "</td>");pw.println("<td>" + ub.getGrade() + "</td>");pw.println("</tr>");}pw.println("</table>");// ================分页功能===============// 上一页if (pageNow != 1) {pw.println("<a href="welcome?pageNow=" mce_href="welcome?pageNow="" + (pageNow - 1)+ ">上一页</a>");}// 显示超链接// for (int i = 1; i <= pageCount; i++) {for (int i = pageNow; i <= pageNow + 4; i++) {pw.println("<a href="welcome?pageNow=" mce_href="welcome?pageNow="" + i + ">" + i + "</a>");}int pageCount=ubc.getPageCount();if (pageNow != pageCount) {pw.println("<a href="welcome?pageNow=" mce_href="welcome?pageNow="" + (pageNow + 1)+ ">下一页</a>");}pw.println("</center></body>");// String u = req.getParameter("uname");// 得到从LoginCl传递的用户名// String p = req.getParameter("pass");} catch (Exception ex) {ex.printStackTrace();}}public void doGet(HttpServletRequest req, HttpServletResponse res)throws ServletException, IOException {process(req, res);}public void doPost(HttpServletRequest req, HttpServletResponse res)throws ServletException, IOException {process(req, res);}public void destroy() {}}

模型层

ConnDB.java(数据库连接)

//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{// 连接数据库Class.forName("com.mysql.jdbc.Driver");// 加载驱动// 得到连接ct = DriverManager.getConnection("jdbc:mysql://localhost:3306/spdb", "root", "root");}catch(Exception ex){ex.printStackTrace();}return ct;}}

UserBean.java(表示users表)

//这是一个UserBean<---------->users表映射//它的一个对象<----------->users表的一条记录对应//数据package com.tsinghua;public class UserBean {private int userId;private String username;private String passwd;private String email;private int grade;public int getUserId() {return userId;}public void setUserId(int userId) {this.userId = userId;}public String getUsername() {return username;}public void setUsername(String username) {this.username = username;}public String getPasswd() {return passwd;}public void setPasswd(String passwd) {this.passwd = passwd;}public String getEmail() {return email;}public void setEmail(String email) {this.email = email;}public int getGrade() {return grade;}public void setGrade(int grade) {this.grade = grade;}}

UserBeanCl.java(业务逻辑控制)

//这是一个处理类（处理users表）<------->操作UserBean//业务逻辑在这里package com.tsinghua;import java.sql.*;import java.util.*;public class UserBeanCl {// 业务逻辑，有一句话：能用私有的就不要用私有private Connection ct = null;private PreparedStatement ps = null;private ResultSet rs = null;private int pageCount = 0;// 共有几页（计算）//返回pageCountpublic 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）// 首先得到rowCount// 连接数据库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pageCountif (rowCount % pageSize == 0) {pageCount = rowCount / pageSize;} else {pageCount = rowCount / pageSize + 1;}ps = ct.prepareStatement("select * from users limit "+ (pageNow - 1) * pageSize + "," + pageSize);// 给问号赋值// ps.setInt(1,(pageNow-1)*pageSize);// ps.setInt(2,pageSize );rs = ps.executeQuery();while (rs.next()) {// 将rs中的每一条记录封装到UserBean ub,实现一号线UserBean ub = new UserBean();ub.setUserId(rs.getInt(1));ub.setUsername(rs.getString(2));ub.setPasswd(rs.getString(3));ub.setEmail(rs.getString(4));ub.setGrade(rs.getInt(5));// 实现第二根线,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 passwd from users where username='"+ u + "'");// ps.setString(1,u);rs = ps.executeQuery();System.out.println("进入验证");if (rs.next()) {System.out.println("有结果");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();}}}