监听器：

package com.cjq.servlet;import javax.servlet.http.HttpSessionEvent;import javax.servlet.http.HttpSessionListener;/** * Application Lifecycle Listener implementation class SessionListener * */public class SessionListener implements HttpSessionListener {		protected static int count = 0;		/**     * @see HttpSessionListener#sessionCreated(HttpSessionEvent)     */    public void sessionCreated(HttpSessionEvent arg0) {    	System.out.println(count);    	count++;    }	/**     * @see HttpSessionListener#sessionDestroyed(HttpSessionEvent)     */    public void sessionDestroyed(HttpSessionEvent arg0) {    	System.out.println(count);    	if(count>0) count--;    }        public static int getCount(){    	return count;    }	}

web.xml配置如下：

    
      
     
      NetWorDemo
       
         
      
       UI/login.html
        
       
         
      
       com.cjq.servlet.SessionListener
        
     
    

Book.java:

package com.cjq.book;import java.sql.Connection;import java.sql.DriverManager;import java.sql.ResultSet;import java.sql.SQLException;import java.sql.Statement;import sun.jdbc.odbc.JdbcOdbcDriver;public class Book {	String sDBDriver = "sun.jdbc.odbc.JdbcOdbcDriver";	String sConnStr = "jdbc:odbc:book";	Connection conn = null;	ResultSet rs = null;	public Book(){		try{			Class.forName(sDBDriver);		}catch(ClassNotFoundException e){			e.printStackTrace();		}	}		public ResultSet executeQuery(String sql){		rs = null;		try{			conn = DriverManager.getConnection(sConnStr);			Statement stmt = conn.createStatement();			stmt = conn.createStatement(ResultSet.TYPE_SCROLL_INSENSITIVE, ResultSet.CONCUR_READ_ONLY);			rs = stmt.executeQuery(sql);		}catch(SQLException ex){			ex.printStackTrace();		}		return rs;	}}

login.html:

    
    
						登录名:
     
     
			
     
						密码:
     
     
			
     
					
     
     
			
     
	
    

login_confirm.jsp:

<%@page import="java.sql.ResultSet"%><%@ page language="java" contentType="text/html; charset=GBK"    pageEncoding="GBK"%>
    
    <%	String name = request.getParameter("login");	name = new String(name.getBytes("UTF-8"));	String pwd = request.getParameter("password");	pwd = new String(pwd.getBytes("UTF-8"));	String sql = "select * from customer where logname='"+name+"' and password='"+pwd+"'";	ResultSet rs = users.executeQuery(sql);	if(rs.next()){		rs.close();		session.putValue("username", name);		%>		
    		<%	}else{		rs.close();		%>		
    		<%			}%>

browse.jsp:

<%@page import="com.cjq.servlet.SessionListener"%><%@page import="java.sql.ResultSet"%><%@ page language="java" contentType="text/html; charset=UTF-8"    pageEncoding="UTF-8"%><%	if(session.getAttribute("username")==null){		response.sendRedirect("login.html");	}	%>	
    <%	int pageSize = 8;	int showPage = 1;	int rowCount = 0;	int pageCount = 0;	ResultSet rs = mybook.executeQuery("select * from book");	rs.last();	rowCount = rs.getRow();	rs.beforeFirst();		pageCount = ((rowCount%pageSize)==0?(rowCount/pageSize):(rowCount/pageSize)+1);	%>
    
    
     
在线人数:<%= SessionListener.getCount() %>
    
    
    
     <%	String toPage = request.getParameter("toPage");	if(toPage!=null){		showPage = Integer.parseInt(toPage);		if(showPage>pageCount){			showPage=pageCount;		}else if(showPage<=0){			showPage=1;		}	}	rs.absolute((showPage-1)*pageSize+1);%>
     
当前在第<%= showPage %>页，共<%= pageCount %>页
     
     
	<%		for(int i=(showPage-1)*pageSize+1;i<=rowCount;i++){			%>			
			<%			rs.next();			if(i==pageSize){				break;			}		}		rs.close();	%>
	      
       
		        
书名
		        
作者
		        
价格(元)
		        
购书
	       
       
				        
<%=rs.getString("name") %>
				        
<%=rs.getString("author") %>
				        
<%=rs.getString("price") %>
				        
">选购此书
			       
      
     
     
        	<%		if(showPage!=1){			%>			
			<%		}		if(showPage!=pageCount){			%>			
			<%		}	%>	
	      
       
        
到第一页
			        
到上一页
        
到下一页
			        
到最后一页
        
	
         
           到 
          页 
         
	
	       
      
     
    

cart.jsp:

<%@page import="java.sql.ResultSet"%><%@ page language="java" contentType="text/html; charset=UTF-8"    pageEncoding="UTF-8"%><%	if(session.getAttribute("username")==null){		response.sendRedirect("login.html");	}%>
    <%	String book_id=request.getParameter("book_id");	String sql = "select id from orders where book_id="+book_id+" and user_name='"+session.getAttribute("username")+"'";	ResultSet rs = cart.executeQuery(sql);	int rowscount=0;	try{		while(rs.next()){			rowscount++;		}	}catch(Exception e){		out.println(e.getMessage());	}	if(rowscount==0){		String sqlBook1 = "select * from book where id="+book_id;		ResultSet rsBook1 = cart.executeQuery(sqlBook1);		while(rsBook1.next()){			String sqlCart="insert into orders (user_name,book_id,book_number,goods_price)"+							"values('"+session.getAttribute("username")+"','"+book_id+"','1',"+rsBook1.getDouble("price")+")";			cart.executeQuery(sqlCart);		}	}else{		String sqlBook2="select * from book where id="+book_id;		ResultSet rsBook2=cart.executeQuery(sqlBook2);		while(rsBook2.next()){			String sqlAdd="update orders set book_number=book_number+1,goods_price="+rsBook2.getDouble("price")+" where book_id="+book_id+" and user_name='"+session.getAttribute("username")+"'";			cart.executeQuery(sqlAdd);		}	}	response.sendRedirect("shopcart.jsp");%>

shopcart.jsp:

<%@page import="java.sql.ResultSet"%><%@ page language="java" contentType="text/html; charset=UTF-8"    pageEncoding="UTF-8"%>
    <%	if(session.getAttribute("username")==null){		response.sendRedirect("login.html");	}%>
    
    
	
     
		      
       
			        
			
         
 
          购书清单 
         
			
		       
	      
     
	
     
		
      
您已选购以下书籍:
		
      
			<%			double g_price,total_price;			g_price=0;			total_price=0;						String sqlList="select * from orders where user_name='"+session.getAttribute("username")+"'";			ResultSet rsList = workM.executeQuery(sqlList);			rsList.beforeFirst();			try{				while(rsList.next()){					int b_num = rsList.getInt("book_number");					%>					
					<%						String sqlBook="select * from book where id="+rsList.getInt("book_id");						ResultSet rsBook = workM.executeQuery(sqlBook);						while(rsBook.next()){							%>							
							<%							g_price=g_price+(double)price*b_num;						}					%>					
					<%				}			}catch(Exception e){				out.println(e);			}			%>			
			       
        
			         
 
          
           购买数量
          
 
			         
 
          
           书名
          
 
			         
 
          
           单价(元)
          
 
			         
 
          
           总价格(元)
          
 
			        
        
					         
 
          
           <%=b_num %>  
          
 
         
 
          
           <%=rsBook.getString("name") %>
          
 
							         
 <% double price = rsBook.getDouble("price"); %> 
          
           ¥<%=price %>
          
 
							         
 
          
           ¥<%=(float)price*b_num %>
          
 
        
        
				         
 
          
           货物价格
          
 
				         
 
          
           ¥<%=(float)g_price %>
          
 
			        
			        
				         
 
          
           运输费用
          
 
				         
 
          
           ¥5.00
          
 
			        
			        
				         
 
          
           总费用
          
 
				         
 
          
           ¥<%=(float)g_price+5 %>
          
 
			        
			        
				         
 继续购书  
			        
		       
      
	
     
	
     
 
    

<%@page import="java.sql.ResultSet"%><%@ page language="java" contentType="text/html; charset=UTF-8"    pageEncoding="UTF-8"%>
    <%	if(session.getAttribute("username")==null){		response.sendRedirect("login.html");	}%><%	String tel = request.getParameter("address");	tel = new String(tel.getBytes("UTF-8"));	String address = request.getParameter("tel");	address = new String(address.getBytes("UTF-8"));	String sqlinsert = "update order set user__address='"+address+"',user_tel='"+tel+"' where user_name='"+session.getAttribute("username")+"'";	workM.executeQuery(sqlinsert);%>
    
    
	
     订单确认	
     
		      
       
		        
			
         
          订单信息
         
		
		       
		       
			        
姓名:
			        
<%=session.getAttribute("username") %>
		       
		       
			        
住址:
			        
<%=address %>
		       
		       
			        
电话:
			        
<%=tel %>
		       
	      
     
	
     
您选购了以下书籍:
	
     
		<%			double g_price=0,total_price=0;			String sqlList = "select * from orders where user_name='"+session.getAttribute("username")+"'";			ResultSet rsList = workM.executeQuery(sqlList);			try{				while(rsList.next()){					int b_num = rsList.getInt("book_number");					%>					
						<%							String sqlBook="select * from book where id="+rsList.getInt("book_id");							ResultSet rsBook=workM.executeQuery(sqlBook);							while(rsBook.next()){								%>								
								<%								g_price=price+(double)price*b_num;							}						%>					
					<%				}			}catch(Exception e){							}		%>		
		      
       
			        
				
         
          购买数量
         
			
			        
				
         
          书名
         
			
			        
				
         
          单价(元)
         
			
			        
				
         
          总价格(元)
         
			
		       
       
						        
							
         
 
           <%=b_num %>   
         
						
        
								
         
          <%=rsBook.getString("name") %>
         
								
								        
								<%								double price = rsBook.getDouble("price");								%>								
         
          ¥<%=price %>
         
								
								        
								
         
          ¥<%=(double)price*b_num %>
         
								
       
       
			        
			
         
          货物价格
         
			
			        
			
         
          ¥<%=(float)g_price %>
         
			
		       
		       
			        
			
         
          运输费用
         
			
			        
			
         
          ¥5.00
         
			
		       
		       
			        
			
         
          总费用
         
			
			        
			
         
          ¥<%=(float)g_price+5 %>