看了韩顺平的j2ee的视频后，吧里面教的做了出来，感觉好极了，新手上路！！！
这个肯定不是原创，但是也不是转载，那我就姑且把它作为翻译吧，给其他看视频学习但是没有代码的同学一点福利吧
首先是login.jsp的登陆界面代码。
<%@ page language="java" import="java.util.*" pageEncoding="gb2312"%>
<%
String path = request.getContextPath();
String basePath = request.getScheme()+"://"+request.getServerName()+":"+request.getServerPort()+path+"/";
%>
<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN">
<html>
<head>
<base href="<%=basePath%>">
<title>My JSP 'login.jsp' starting page</title>
<meta http-equiv="pragma" content="no-cache">
<meta http-equiv="cache-control" content="no-cache">
<meta http-equiv="expires" content="0">
<meta http-equiv="keywords" content="keyword1,keyword2,keyword3">
<meta http-equiv="description" content="This is my page">
<!--
<link rel="stylesheet" type="text/css" href="styles.css">
-->
</head>
<body bgcolor="pink">
<center>
用户登录 <br>
<hr>
<!-- <form action="loginCl.jsp" method="post"> -->
<form action="LoginClServlet" method="post">
用户名: <input type="text" name="username"><br>
密 码: <input type="password" name="passwd"><br>
<input type="submit" value="登录">
<input type="reset" value="重置">
</form>
</center>
</body>
</html>
<%@ page language="java" import="java.util.*,java.sql.*,com.xf.model.*" pageEncoding="gb2312"%>
<%
String path = request.getContextPath();
String basePath = request.getScheme()+"://"+request.getServerName()+":"+request.getServerPort()+path+"/";
%>
<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN">
<html>
<head>
<base href="<%=basePath%>">
<title>My JSP 'wel.jsp' starting page</title>
<meta http-equiv="pragma" content="no-cache">
<meta http-equiv="cache-control" content="no-cache">
<meta http-equiv="expires" content="0">
<meta http-equiv="keywords" content="keyword1,keyword2,keyword3">
<meta http-equiv="description" content="This is my page">
<!--
<link rel="stylesheet" type="text/css" href="styles.css">
-->
</head>
<body>
登录成功！！！恭喜发财！！！<%=request.getParameter("user") %><br>
<a href="login.jsp">返回重新登录</a>
<hr>
<h1>用户信息列表</h1>
<%
/*
//定义四个变量
int pageNow=1; //默认从第一页开始
int pageSize=3; //一共的页数
int rowCount=0; //这个从数据库查询
int pageCount=0; //通过rowCount和pageSize求得
String s_pageNow=request.getParameter("pageNow");
if(s_pageNow != null)
{
//从超链接处得到值
pageNow=Integer.parseInt(s_pageNow);
}
//1.加载驱动
Class.forName("com.microsoft.sqlserver.jdbc.SQLServerDriver");
//2.得到链接
Connection ct=DriverManager.getConnection("jdbc:sqlserver://localhost:1433;databaseName=spdb1","sa","");
//3.创建statement
Statement sm=ct.createStatement();
//4.到数据库中查询
ResultSet rs=sm.executeQuery("select count(*) from users");
//5.对查询结果进行判断
//这里注意一定要next，不然GG思密达
if(rs.next())
{
rowCount=rs.getInt(1);
}
//计算pageCount，算法很多
if(rowCount%pageSize == 0)
{
pageCount=rowCount/pageSize;
}
else
{
pageCount=rowCount/pageSize+1;
}
//查出要显示出来的记录
rs=sm.executeQuery("select top "+pageSize+" * from users where userId not in (select top "
+pageSize*(pageNow-1)+" userId from users)");
*/
//调用UserBeanCl的方法（创建一个UserBeanCl的实例然后调用他的方法），完成分页显示
// UserBeanCl ubc=new UserBeanCl();
// ArrayList a1=ubc.getUsersByPage(pageNow);
//要显示的用户信息从request中取
ArrayList a1=(ArrayList)request.getAttribute("result");
//显示出来
%>
<table border="1">
<tr><td>用户id</td><td>用户名字</td><td>密码</td><td>电子邮件</td><td>用户级别</td></tr>
<%
//while(rs.next())
for(int i=0 ; i<a1.size() ; ++i)
{
//重arraylist中取出UserBean
UserBean ub=(UserBean)a1.get(i);
%>
<tr><td><%=ub.getUserId() %></td><td><%=ub.getUsername() %></td><td><%=ub.getPasswd() %></td><td><%=ub.getEmail() %></td><td><%=ub.getGrade() %></td></tr>
<%
}
%>
</table>
<%
//首页
out.println("<a href=UserClServlet?pageNow="+1+">[首页]</a>");
//String s_pageNow=(String)request.getAttribute("pageNow");
int pageNow=Integer.parseInt((String)request.getAttribute("pageNow"));
//上一页
if(pageNow != 1)
{
out.println("<a href=UserClServlet?pageNow="+(pageNow-1)+">[上一页]</a>");
}
//得到pageCount
// int pageCount=ubc.getPageCount();
String s_pageCount=(String)request.getAttribute("pageCount");
int pageCount=Integer.parseInt(s_pageCount);
//显示超链接
for(int i=1 ; i<=pageCount ; ++i)
{
out.println("<a href=UserClServlet?pageNow="+i+">["+i+"]</a>");
}
//下一页
if(pageNow != pageCount)
{
out.println("<a href=UserClServlet?pageNow="+(pageNow+1)+">[下一页]</a>");
}
//尾页
out.println("<a href=UserClServlet?pageNow="+pageCount+">[尾页]</a>");
%>
</body>
</html>
/**
* 功能：这是一个控制器，完成对用户身份的验证，本身是不会去完成业务逻辑的
* 它主要是去调用model完成对数据的处理
* 时间：2014年6月5日12:56:46
* 作者：cutter_point
*/
package com.xf.controller;
import com.xf.model.*;
import java.io.IOException;
import java.io.PrintWriter;
import java.util.*;
import javax.servlet.ServletException;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
public class LoginClServlet extends HttpServlet
{
/**
* The doGet method of the servlet. <br>
*
* This method is called when a form has its tag value method equals to get.
*
* @param request the request send by the client to the server
* @param response the response send by the server to the client
* @throws ServletException if an error occurred
* @throws IOException if an error occurred
*/
public void doGet(HttpServletRequest request, HttpServletResponse response)
throws ServletException, IOException
{
//得到账号密码
String u=request.getParameter("username"); //账号
String p=request.getParameter("passwd"); //密码
//调用模型对他进行验证
UserBeanCl ubc=new UserBeanCl();
if(ubc.checkUser(u, p))
{
System.out.println("这是使用的Servlet完成验证！！");
//合法
//跳转
//response.sendRedirect("wel.jsp");
//在进入wel.jsp之前把数据都准备好
//首先显示的是默认的第一页
ArrayList al=ubc.getUsersByPage(1);
int pageCount=ubc.getPageCount();
request.setAttribute("result", al);
request.setAttribute("pageCount", pageCount+"");
request.setAttribute("pageNow", "1");
//但是上面方法效率不高,高效率的是
request.getRequestDispatcher("wel.jsp?user="+u).forward(request, response);
}
else
{
//不合法
// response.sendRedirect("login.jsp");
//理由同上
request.getRequestDispatcher("login.jsp").forward(request, response);
}
}
/**
* The doPost method of the servlet. <br>
*
* This method is called when a form has its tag value method equals to post.
*
* @param request the request send by the client to the server
* @param response the response send by the server to the client
* @throws ServletException if an error occurred
* @throws IOException if an error occurred
*/
public void doPost(HttpServletRequest request, HttpServletResponse response)
throws ServletException, IOException
{
this.doGet(request, response);
}
}/**
* 功能：这个控制器将处理用户的分页显示，用户的删除修改查询，添加
* 时间：2014年6月5日13:47:03
* 作者：cutter_point
*/
package com.xf.controller;
import com.xf.model.*;
import java.io.IOException;
import java.io.PrintWriter;
import java.util.ArrayList;
import javax.servlet.ServletException;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
public class UserClServlet extends HttpServlet
{
/**
* The doGet method of the servlet. <br>
*
* This method is called when a form has its tag value method equals to get.
*
* @param request the request send by the client to the server
* @param response the response send by the server to the client
* @throws ServletException if an error occurred
* @throws IOException if an error occurred
*/
public void doGet(HttpServletRequest request, HttpServletResponse response)
throws ServletException, IOException
{
//得到用户希望显示的pageNow
String s_pageNow=request.getParameter("pageNow");
//使用UserBeanCl的方法调用得到pageNow
try
{
int pageNow=Integer.parseInt(s_pageNow);
//调用UserBeanCl
UserBeanCl ubc=new UserBeanCl();
//在进入wel.jsp之前把数据都准备好
ArrayList al=ubc.getUsersByPage(pageNow);
int pageCount=ubc.getPageCount();
request.setAttribute("result", al);
request.setAttribute("pageCount", pageCount+"");
request.setAttribute("pageNow", pageNow+"");
// request.setAttribute("pageNow", pageNow); 不行必须在后面加引号，不然没法用，因为别人
//默认吧pageNow看成string了，结果传过去了，以为是String类型，实际是int类型，结果就出错了
System.out.println("分页是使用了UserClServlet!!");
//从新跳转回wel.jsp里面去
request.getRequestDispatcher("wel.jsp").forward(request, response);
}
catch (Exception e)
{
// TODO: handle exception
e.printStackTrace();
}
}
/**
* The doPost method of the servlet. <br>
*
* This method is called when a form has its tag value method equals to post.
*
* @param request the request send by the client to the server
* @param response the response send by the server to the client
* @throws ServletException if an error occurred
* @throws IOException if an error occurred
*/
public void doPost(HttpServletRequest request, HttpServletResponse response)
throws ServletException, IOException
{
this.doGet(request, response);
}
}
分别是：UserBean.java,UserBeanCl.java,ConnDB.java
/**
* 功能：这是一个javabean,对应users表，代表数据
* 时间：2014年6月4日10:39:33
* 作者：cutter_point
*/
package com.xf.model;
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;
}
}
/**
* 功能：这是一个处理类，也叫做bo，主要封装对users表的各种操作
* 每一个UserBean对象放到ArrayList里面去，更早关闭和数据库链接
* 时间：2014年6月4日10:43:48
* 作者：cutter_point
*/
package com.xf.model;
import java.sql.*;
import java.util.*;
public class UserBeanCl
{
private Statement sm=null;
private ResultSet rs=null;
private Connection ct=null;
private int pageSize=3; //默认从第一页开始
private int rowCount=0; //这个从数据库查询
private int pageCount=0; //通过rowCount和pageSize求得
public void close()
{
try
{
if(rs != null)
{
rs.close();
rs=null;
}
if(sm != null)
{
sm.close();
sm=null;
}
if(ct != null)
{
ct.close();
ct=null;
}
}
catch (Exception e)
{
// TODO Auto-generated catch block
e.printStackTrace();
}
}
//得到pageCount，页数总计
public int getPageCount()
{
try
{
//得到链接
ct=new ConnDB().getConn();
//声明，创建一个sm
sm=ct.createStatement();
//4.到数据库中查询
ResultSet rs=sm.executeQuery("select count(*) from users");
//这里注意一定要next，不然GG思密达
if(rs.next())
{
rowCount=rs.getInt(1);
}
//计算pageCount的结果
if(rowCount%pageSize == 0)
{
pageCount=rowCount/pageSize;
}
else
{
pageCount=rowCount/pageSize+1;
}
}
catch (Exception e)
{
// TODO: handle exception
e.printStackTrace();
}
finally
{
this.close();
}
return pageCount;
}
//得到用户需要显示地信息（分页）
public ArrayList getUsersByPage(int pageNow)
{
ArrayList a1=new ArrayList();
try
{
//得到链接
ct=new ConnDB().getConn();
//创建statement
sm=ct.createStatement();
//查询出需要显示地信息
rs=sm.executeQuery("select top "+pageSize+" * from users where userId not in (select top "
+pageSize*(pageNow-1)+" userId from users)");
//吧得到的信息存放到ArrayList上面去
while(rs.next())
{
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));
//将ub放到arraylist里面去
a1.add(ub);
}
}
catch (Exception e)
{
e.printStackTrace();
// TODO: handle exception
}
finally
{
//关闭资源
this.close();
}
return a1;
}
//检查账号密码是否正确
public boolean checkUser(String u, String p)
{
boolean b=false;
try
{
//到数据库中去验证
ct=new ConnDB().getConn();
//3、创建statement
sm=ct.createStatement();
//4、进行查询,把查询第一个结果放到rs中
rs=sm.executeQuery("select passwd from users where username='"+u+"'");
//根据结果来判断是否是要寻找的数据
if(rs.next())
{
//用户名存在，验证密码
if(rs.getString(1).equals(p))
{
b=true;
}
}
}
catch (Exception e)
{
e.printStackTrace();
// TODO: handle exception
}
finally
{
this.close();
}
return b;
}
}/**
* 功能：得到数据库的链接
* 时间：2014年6月4日10:47:57
* 作者：cutter_point
*/
package com.xf.model;
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、得到链接
ct=DriverManager.getConnection("jdbc:sqlserver://localhost:1433;databaseName=spdb1","sa","");
} catch (Exception e)
{
// TODO Auto-generated catch block
e.printStackTrace();
}
return ct;
}
}
PS:不断努力，默默学习！！！
原文地址：http://blog.csdn.net/cutter_point/article/details/28621223
