声明：作者原创，版权所有。未经授权，不得转载
在jsp中用bean和servlet联合实现用户注册、登录

作者：imagebear
版权：imagebear

本例需要的软件和运行环境：
1、Windows2000 Server操作系统
2、jdk1.4
3、JCreator2.5（java源码编辑调试器，吐血推荐！）
4、Macromedia JRun MX
5、Macromedia Dreamweaver MX（非必需）
6、MySQL数据库（最好安装MySQL Control Center）

一、数据库设计
用MySQL Control Center打开MySQL数据库，新建数据库shopping，在其下新建表tbl_user，其中各字段设置如下：

二、编写连接数据库bean：DBConn.java

//DBConn.java

//include required classes
import java.sql.*;

//==========================================
// Define Class DBConn
//==========================================
public class DBConn
{
 public String sql_driver = "org.gjt.mm.mysql.Driver";
 public String sql_url = "jdbc:mysql://localhost:3306";
 public String sql_DBName = "shopping";
 public String user = "sa";
 public String pwd = ";

 Connection conn = null;
 Statement stmt = null;
 ResultSet rs = null;

 public boolean setDriver(String drv)
 {
  this.sql_driver = drv;
  return true;
 }

 public String getDriver()
 {
  return this.sql_driver;
 }

 public boolean setUrl(String url)
 {
  this.sql_url = url;
  return true;
 }

 public boolean setDBName(String dbname)
 {
  this.sql_DBName = dbname;
  return true;
 }

 public String getDBName()
 {
  return this.sql_DBName;
 }

 public boolean setUser(String user)
 {
  this.user = user;
  return true;
 }

 public String getUser()
 {
  return this.user;
 }

 public boolean setPwd(String pwd)
 {
  this.pwd = pwd;
  return true;
 }

 public String getPwd()
 {
  return this.pwd;
 }

 public DBConn()
 {
  try{
   Class.forName(sql_driver);//加载数据库驱动程序
   this.conn = DriverManager.getConnection(sql_url + "/" + sql_DBName + "?user=" + user + "password=" + pwd + "useUnicode=truecharacterEncoding=gb2312");
   this.stmt = this.conn.createStatement();
  }catch(Exception e){
   System.out.println(e.toString());
  }
 }

                //执行查询操作
 public ResultSet executeQuery(String strSql)
 {
  try{
   this.rs = stmt.executeQuery(strSql);
   return this.rs;
  }catch(SQLException e){
   System.out.println(e.toString());
   return null;
  }catch(NullPointerException e){
   System.out.println(e.toString());
   return null;
  }
 }

                //执行数据的插入、删除、修改操作
 public boolean execute(String strSql)
 {
  try{
   if(this.stmt.executeUpdate(strSql) == 0)
    return false;
   else
    return true;
  }catch(SQLException e){
   System.out.println(e.toString());
   return false;
  }catch(NullPointerException e){
   System.out.println(e.toString());
   return false;
  }
 }

                //结果集指针跳转到某一行
 public boolean rs_absolute(int row)
 {
  try{
   this.rs.absolute(row);
   return true;
  }catch(SQLException e){
   System.out.println(e.toString());
   return false;
  }
 }

 public void rs_afterLast()
 {
  try{
   this.rs.afterLast();
  }catch(SQLException e){
   System.out.println(e.toString());
  }
 }

 public void rs_beforeFirst()
 {
  try{
   this.rs.beforeFirst();
  }catch(SQLException e){
   System.out.print(e.toString());
  }
 }

 public void rs_close()
 {
  try{
   this.rs.close();
  }catch(SQLException e){
   System.out.print(e.toString());
  }
 }

 public void rs_deleteRow()
 {
  try{
   this.rs.deleteRow();
  }catch(SQLException e){
   System.out.print(e.toString());
  }
 }

 public boolean rs_first()
 {
  try{
   this.rs.first();
   return true;
  }catch(SQLException e){
   System.out.print(e.toString());
   return false;
  }
 }

 public String rs_getString(String column)
 {
  try{
   return this.rs.getString(column);
  }catch(SQLException e){
   System.out.println(e.toString());
   return null;
  }
 }

                //此方法用于获取大段文本，
                //将其中的回车换行替换为br>
                //输出到html页面
 public String rs_getHtmlString(String column)
 {
  try{
   String str1 = this.rs.getString(column);
   String str2 = "\r\n";
   String str3 = "br>";
   return this.replaceAll(str1,str2,str3);
  }catch(SQLException e){
   System.out.println(e.toString());
   return null;
  }
 }

                //把str1字符串中的str2字符串替换为str3字符串
 private static String replaceAll(String str1,String str2,String str3)
 {
  StringBuffer strBuf = new StringBuffer(str1);
     int index=0;
  while(str1.indexOf(str2,index)!=-1)
  {
   index=str1.indexOf(str2,index);
   strBuf.replace(str1.indexOf(str2,index),str1.indexOf(str2,index)+str2.length(),str3);
   index=index+str3.length();

    str1=strBuf.toString();
  }
  return strBuf.toString();
 }

 public int rs_getInt(String column)
 {
  try{
   return this.rs.getInt(column);
  }catch(SQLException e){
   System.out.println(e.toString());
   return -1;
  }
 }

 public int rs_getInt(int column)
 {
  try{
   return this.rs.getInt(column);
  }catch(SQLException e){
   System.out.println(e.toString());
   return -1;
  }
 }

 public boolean rs_next()
 {
  try{
   return this.rs.next();
  }catch(SQLException e){
   System.out.println(e.toString());
   return false;
  }
 }

                //判断结果集中是否有数据
 public boolean hasData()
 {
  try{
   boolean has_Data = this.rs.first();  
   this.rs.beforeFirst();
   return has_Data;
  }catch(SQLException e){
   System.out.println(e.toString());
   return false;
  }
 }

 public boolean rs_last()
 {
  try{
   return this.rs.last();
  }catch(SQLException e){
   System.out.println(e.toString());
   return false;
  }
 }

 public boolean rs_previous()
 {
  try{
   return this.rs.previous();
  }catch(Exception e){
   System.out.println(e.toString());
   return false;
  }
 }

                //main方法，调试用
 public static void main(String args[])
 {
  try{
   DBConn myconn = new DBConn();
   //myconn.setDBName("shopping");
   //myconn.DBConn();
   //myconn.execute("Insert Into tbl_test(id,name) values('10','shandaer')");
   //myconn.execute("Update tbl_test set name='yyyyyyyyyyyy' where id=10");
   //myconn.execute("Delete from tbl_test where id=1");
   ResultSet rs = myconn.executeQuery("select * from tbl_user order by id desc limit 1");
   //boolean hasData = myconn.hasData();
   //System.out.println("has data:" + hasData);
   //rs.first();
   while (myconn.rs.next()) 
   {
    int id = myconn.rs_getInt("id") + 1;
    System.out.print(id);
    System.out.println(myconn.rs_getInt("id") + myconn.rs_getString("name"));

    //System.out.println('\n' + myconn.rs_getHtmlString("name"));
    //System.out.println(myconn.rs.getString("name") + myconn.rs_getInt(1));
   }
  }catch(Exception e){
   System.err.println(e.toString());
  }
 }

}

声明：因为使用的是MySQL数据库，所以需要MySQL数据库的驱动
下载后请将org包放至DBConn.java所在目录下
以确保该bean能正常运行

三、编写用户注册的bean：reg.java

//reg.java

//import required classes
import java.sql.*;

public class reg
{
 public int newID = 0;
 public boolean result = false;
 public boolean reg(String username,String password,String confirm,String email)
 {
  try{
   if(!this.checkUser(username))
    return false;
   if(!this.checkPwd(password))
    return false;
   if(!this.verifyPwd(password,confirm))
    return false;
   if(!this.checkEmail(email))
    return false;
   if(!this.userNotExit(username))
    return false;
   this.getNewID(); 
   this.result = this.register(username,password,confirm,email);
   return this.result;
  }catch(Exception e){
   System.out.println(e.toString());
   return false;
  }
 }//End boolean reg

 public boolean checkUser(String user)
 {
  try{  
   if(user.indexOf("'")!=-1)
   {
    System.out.println("姓名中含有非法字符！");
    return false;
   }else
    return true;
  }catch(Exception e){
   System.out.println(e.toString());
   return false;
   }
 }

 public boolean checkPwd(String pwd)
 {
  try{
   if(pwd.indexOf("'")!=-1)
   {
    System.out.println("密码中含有非法字符！");
    return false;
   }else
    return true;
  }catch(Exception e){
   System.out.println(e.toString());
   return false;
  }
 }

 public boolean verifyPwd(String pwd,String confirm)
 {
  try{
   if(!pwd.equals(confirm))
   {
    System.out.println("两次输入的密码不一致！");
    return false;
   }else
    return true;
  }catch(Exception e){
   System.out.println(e.toString());
   return false;
  }
 }

 public boolean checkEmail(String email)
 {
  try{
   if(email.indexOf("'")!=-1)
   {
    System.out.println("E-mail中含有非法字符！");
    return false;
   }else
    return true;
  }catch(Exception e){
   System.out.println(e.toString());
   return false;
  }
 }

 public boolean userNotExit(String user)
 {
  try{
   DBConn userDBConn = new DBConn();
   userDBConn.executeQuery("select * from tbl_user where name='" + user + "'");
   if(userDBConn.rs_next())
   {
    System.out.println("用户名已存在，请选择其它的用户名！");
    return false;
   }else
    return true;
  }catch(Exception e){
   System.out.println(e.toString());
   return false;
   }
 }

 public int getNewID()
 {
  try{
   DBConn newIDDBConn = new DBConn();
   newIDDBConn.executeQuery("select * from tbl_user order by id desc limit 1");
   if(newIDDBConn.rs_next())
   {
    this.newID = newIDDBConn.rs_getInt("id") + 1;
    System.out.println(this.newID);
   }else{
    this.newID = 1;
   }
   return this.newID;
  }catch(Exception e){
   System.out.println(e.toString());
   return -1;
   }   
 }

 public int getID()
 {
  return this.newID;
 }

 public boolean register(String username,String password,String confirm,String email)
 {
  try{
   DBConn regDBConn = new DBConn();
   String strSQL = "insert into tbl_user(id,name,pwd,email) values('" + this.newID +"','" + username + "','" + password + "','" + email + "')";
   regDBConn.execute(strSQL);
   return true;
  }catch(Exception e){
   System.out.println(e.toString());
   return false;
   }
 }

 public static void main(String args[])
 {
  try{

   reg newreg = new reg();  

   System.out.println(newreg.reg("sssssssss","ssssss","ssssss","imagebear@163.com"));

   DBConn myconn = new DBConn();
   myconn.executeQuery("select * from tbl_user");
   while(myconn.rs_next())
   {
    System.out.println(myconn.rs_getInt("id") + "    " + myconn.rs_getString("name") + "    " + myconn.rs_getString("pwd") + "    " + myconn.rs_getString("email"));
   }
   System.out.println(newreg.getID());
  }catch(Exception e){
   System.err.println(e.toString());
  }
 }
};

说明：
1、该bean文件应和上文所述DBConn.class文件放于同一目录下
2、本例主要研究注册的过程，其中的Email检测等方法并不完善，若要应用请自行设计方法

四、编写用户登陆的Servlet：login.java

//login.java

//import required classes
import java.io.*;
import javax.servlet.*;
import javax.servlet.http.*;
import java.sql.*;

//class login
public class login extends HttpServlet
{
 public void doGet(HttpServletRequest req,HttpServletResponse res)
 throws IOException,ServletException
 {
  String username = req.getParameter("username");
  String password = req.getParameter("password");
  if(this.checklogin(username,password))
  {
   Cookie mylogin = new Cookie("username",username);
   mylogin.setVersion(1);
   mylogin.setPath("/");
   mylogin.setComment("Your login username");
   res.addCookie(mylogin);
  }
  //Cookie[] myCookies = req.getCookies();
  //String nameValue = this.getCookieValue(myCookies,"username","not found");
  //PrintWriter out = res.getWriter();
  //out.println("username" + ":" + nameValue);
  //out.println("Test Cookie Success!");
  res.sendRedirect("/index.jsp");
 }

 public void doPost(HttpServletRequest req,HttpServletResponse res)
 throws IOException,ServletException
 {
  doGet(req,res);
 }

 public static String getCookieValue(Cookie[] cookies,String cookieName,String defaultValue)
 {
  for(int i=0;icookies.length;i++) {
  Cookie cookie = cookies[i];
  if (cookieName.equals(cookie.getName()))
  return(cookie.getValue());
 }
  return(defaultValue);
 }

 public boolean checklogin(String username,String password)
 {
  try{
   DBConn loginConn = new DBConn();
   loginConn.executeQuery("select * from tbl_user where name='" + username + "'");
   if(loginConn.rs_next())
   {
    System.out.println("Connection created!");
    if(loginConn.rs_getString("pwd").trim().equals(password))
    {
     System.out.println(loginConn.rs_getString("name"));
     return true;
    }
    else
    {
     return false;
    }
   }
   System.out.println("Test Login Success!");
   return false;
  }catch(Exception e){
   System.out.println(e.toString());
   return false;
   }
 }

 public static void main(String args[])
 {
  login mylogin = new login();
  System.out.println(mylogin.checklogin("shandong","shandong"));
 }

}

说明：
1、默认的jdk1.4中并没有servlet包，请至sun公司网页下载servlet.jar，放至jdk目录下的jre\lib\目录下，并在JCreator中设置jdk处添加servlet.jar包 

2、本Servlet用于检验用户名和密码，若正确则将用户名写入Cookie，完成后将当前页重定向到index.jsp页

五、编写检测用户是否已经登陆的bean：checkLogin.java

//checkLogin.java

//import required classes
import java.io.*;
import javax.servlet.*;
import javax.servlet.http.*;

//class checkLogin
public class checkLogin
{
 public String username = ";

 public boolean check(HttpServletRequest req,HttpServletResponse res)
 throws IOException,ServletException
 {
  String cookieName = "username";
  Cookie[] myCookies = req.getCookies();
  this.username = this.getCookieValue(myCookies,cookieName,"not found");
  PrintWriter out = res.getWriter();
  if(this.username != null)
  {  
   //out.println("早上好，" + this.username + "！");
   return true;
  }else{
   out.println("登陆失败！");
   return false;
   }

 }

 public String getUserName()
 {
  return this.username;
 }

 public static String getCookieValue(Cookie[] cookies,String cookieName,String defaultValue)
 {
  for(int i=0;icookies.length;i++) {
  Cookie cookie = cookies[i];
  if (cookieName.equals(cookie.getName()))
  return(cookie.getValue());
 }
  return(defaultValue);
 }
}

说明：此bean检测cookie中的username，若不为空则说明已登录，反之说明没有登录。方法不够完善，您可以自行扩充。

六、在JRun中建立shopping服务器
打开JRun Administrator，新建shopping服务器，这里端口为8101。
将上文所述所有编译后的class文件连同org包拷至JRun的shopping服务器所在目录中的classes文件夹下，路径为：

C:\JRun4\servers\shopping\default-ear\default-war\WEB-INF\classes\

七、建立jsp文件
应用DW，在C:\JRun4\servers\shopping\default-ear\default-war\目录下新建如下的jsp文件：
index.jsp：

%@ page contentType="text/html;charset=gb2312" pageEncoding="gb2312" %>
html>
head>
title>Shopping123/title>
meta http-equiv="Content-Type" content="text/html; charset=gb2312">
link href="styles/shoppingstyle.css" rel="stylesheet" type="text/css">
/head>
body bgcolor="#FFFFFF" leftmargin="0" topmargin="0">
jsp:useBean id="checklogin" class="checkLogin" scope="page"/>
%
 boolean login = checklogin.check(request,response);
%>
table width="100%" height="100%" border="0" cellpadding="0" cellspacing="0">
  tr bgcolor="#990000">
    td height="80" colspan="5">table width="100%" height="100%" border="0" cellpadding="0" cellspacing="0">
        tr>
          td width="120">nbsp;/td>
          td class="caption">Shopping123/td>
          td width="200">nbsp;/td>
        /tr>
      /table>/td>
  /tr>
  tr>
    td width="200" align="center" valign="top">table width="100%" height="20" border="0" cellpadding="0" cellspacing="0">
        tr>
          td>nbsp;/td>
        /tr>
      /table>
   %
    if(!login){
   %>
      table width="90%" border="0" align="center" cellpadding="0" cellspacing="1" bgcolor="#CCCCCC">
   form name="form1" method="post" action="/servlet/login">
        tr align="center" bgcolor="#CCCCCC">
          td height="30" colspan="2" class="deepred">卖场入口/td>
        /tr>
        tr>
          td width="50%" height="24" align="center" bgcolor="#FFFFFF">会员/td>
          td align="center" bgcolor="#FFFFFF">input name="username" type="text" id="username" size="10">/td>
        /tr>
        tr>
          td height="24" align="center" bgcolor="#FFFFFF">密码/td>
          td align="center" bgcolor="#FFFFFF">input name="password" type="text" id="password" size="10">/td>
        /tr>
        tr>
          td height="24" align="center" bgcolor="#FFFFFF">a href="reg.jsp" target="_blank" class="red">注册/a>/td>
          td align="center" bgcolor="#FFFFFF">input type="submit" name="Submit" value="进入">/td>
        /tr>
  /form>
      /table>
   %
    }
  else
  {
   out.println("您好，" + checklogin.getUserName() + "!");
  }
   %>
   /td>
 td width="1" valign="top" bgcolor="#CCCCCC">/td>
    td width="400">nbsp;/td>
 td width="1" valign="top" bgcolor="#CCCCCC">/td>
    td width="200">nbsp;/td>
  /tr>
  tr align="center" bgcolor="#990000">
    td height="60" colspan="5" class="white">copyrightcopy; 2003 Shopping123/td>
  /tr>
/table>
/body>
/html>

reg.jsp%@ page contentType="text/html;charset=gb2312" pageEncoding="gb2312" %>
html>
head>
title>Shopping123/title>
meta http-equiv="Content-Type" content="text/html; charset=gb2312">
link href="styles/shoppingstyle.css" rel="stylesheet" type="text/css">
/head>
body bgcolor="#FFFFFF" leftmargin="0" topmargin="0">
table width="100%" height="100%" border="0" cellpadding="0" cellspacing="0">
  tr bgcolor="#990000">
    td height="80" colspan="5">table width="100%" height="100%" border="0" cellpadding="0" cellspacing="0">
        tr>
          td width="120">nbsp;/td>
          td class="caption">Shopping123/td>
          td width="200">nbsp;/td>
        /tr>
      /table>/td>
  /tr>
  tr>
    td width="100" align="center" valign="top">nbsp;/td>
    td width="1" valign="top">/td>
    td width="400" align="center" valign="top">table width="100%" height="20" border="0" cellpadding="0" cellspacing="0">
        tr>
          td>nbsp;/td>
        /tr>
      /table>
      table width="100%" border="0" cellpadding="0" cellspacing="1" bgcolor="#CCCCCC">
   form action="regpost.jsp" method="post" name="form1">
        tr align="center">
          td height="30" colspan="2" bgcolor="#CCCCCC" class="deepred">会员注册/td>
        /tr>
        tr>
          td width="50%" height="24" align="center" bgcolor="#FFFFFF">会员/td>
          td align="center" bgcolor="#FFFFFF">input name="username" type="text" id="username" size="16">/td>
        /tr>
        tr>
          td width="50%" height="24" align="center" bgcolor="#FFFFFF">密码/td>
          td align="center" bgcolor="#FFFFFF">input name="password" type="password" id="password" size="16">/td>
        /tr>
        tr>
          td width="50%" height="24" align="center" bgcolor="#FFFFFF">验证密码/td>
          td align="center" bgcolor="#FFFFFF">input name="confirm" type="password" id="confirm" size="16">/td>
        /tr>
        tr>
          td width="50%" height="24" align="center" bgcolor="#FFFFFF">E-mail/td>
          td align="center" bgcolor="#FFFFFF">input name="email" type="text" id="email" size="16">/td>
        /tr>
        tr>
          td width="50%" height="24" align="center" bgcolor="#FFFFFF">input type="submit" name="Submit" value="重写">/td>
          td align="center" bgcolor="#FFFFFF">input type="submit" name="Submit2" value="注册">/td>
        /tr>
  /form>
      /table>/td>
    td width="1" valign="top">/td>
    td width="100">nbsp;/td>
  /tr>
  tr align="center" bgcolor="#990000">
    td height="60" colspan="5" class="white">copyrightcopy; 2003 Shopping123/td>
  /tr>
/table>
/body>
/html>
 regpost.jsp：注册表单提交页面%@ page contentType="text/html;charset=gb2312" pageEncoding="gb2312" %>
%@ page import="reg"%>
html>
head>
title>Shopping123/title>
meta http-equiv="Content-Type" content="text/html; charset=gb2312">
link href="styles/shoppingstyle.css" rel="stylesheet" type="text/css">
/head>
body bgcolor="#FFFFFF" leftmargin="0" topmargin="0">
%
 String username = new String(request.getParameter("username").getBytes("ISO8859_1")).trim();
 String password = new String(request.getParameter("password").getBytes("ISO8859_1")).trim();
 String confirm = new String(request.getParameter("confirm").getBytes("ISO8859_1")).trim();
 String email = new String(request.getParameter("email").getBytes("ISO8859_1")).trim();
%>
table width="100%" height="100%" border="0" cellpadding="0" cellspacing="0">
  tr bgcolor="#990000">
    td height="80" colspan="5">table width="100%" height="100%" border="0" cellpadding="0" cellspacing="0">
        tr>
          td width="120">nbsp;/td>
          td class="caption">Shopping123/td>
          td width="200">nbsp;/td>
        /tr>
      /table>/td>
  /tr>
  tr>
    td width="100" align="center" valign="top">nbsp;/td>
    td width="1" valign="top">/td>
    td width="400" align="center" valign="top">
table width="100%" height="20" border="0" cellpadding="0" cellspacing="0">
        tr>
          td>nbsp;/td>
        /tr>
      /table>
jsp:useBean id="regID" class="reg" scope="session"/>
%
 if(regID.reg(username,password,confirm,email))
 {
  out.print("ok");
  String newID = regID.getID() + ";
%>
      table width="100%" border="0" cellpadding="0" cellspacing="1" bgcolor="#CCCCCC">
        tr align="center">
          td height="30" colspan="2" bgcolor="#CCCCCC" class="deepred">恭喜您，注册成功！/td>
        /tr>
        tr>
          td width="50%" height="24" align="center" bgcolor="#FFFFFF">编号/td>
          td align="center" bgcolor="#FFFFFF">%=newID%>/td>
        /tr>
        tr>
          td width="50%" height="24" align="center" bgcolor="#FFFFFF">会员/td>
          td align="center" bgcolor="#FFFFFF">%=username%>/td>
        /tr>
        tr>
          td width="50%" height="24" align="center" bgcolor="#FFFFFF">密码/td>
          td align="center" bgcolor="#FFFFFF">%=password%>/td>
        /tr>
        tr>
          td width="50%" height="24" align="center" bgcolor="#FFFFFF">E-mail/td>
          td align="center" bgcolor="#FFFFFF">%=email%>/td>
        /tr>
      /table>
%
  out.print("br>");
  out.print("a href=javascript:window.close()>关闭/a>");
 }else{
  out.print("注册失败！br>");
  out.print("该用户名已有人使用，请使用另外的用户名！");
  out.print("a href=javascript:history.go(-1)>返回/a>");
 }
%>
   /td>
    td width="1" valign="top">/td>
    td width="100">nbsp;/td>
  /tr>
  tr align="center" bgcolor="#990000">
    td height="60" colspan="5" class="white">copyrightcopy; 2003 Shopping123/td>
  /tr>
/table>
/body>
/html>
 至此，我们已经完成了一个用户注册、登录的系统。 因为这是本人自己边学边做完成的，所以代码一定有很多不完善的地方，欢迎大家批评指正。 以上所有代码均经本人测试通过。