引用：http://bbs.hh010.com/thread-32010-2-1.html
//下面這兩個是連接配接池,下面兩個檔案都放在一個mybean的包裡.
package mybean;
import java.sql.*;
import java.util.*;
public class DBConnPool {
//正在使用連接配接的數量
private int using;
//目前可用的連接配接數,即空閑連接配接
private Vector connections=new Vector();
//最大連接配接數
private int maxconn;
//連接配接池名
private String poolname;
//資料庫辨別
private String dbid;
//驅動程式名
private String drivername;
//資料庫帳号
private String username;
//資料庫密碼
private String passwd;
public DBConnPool(String poolname,String dbid,String drivername,
String username,String passwd,int maxconn){
this.poolname=poolname;
this.drivername=drivername;
this.dbid =dbid;
this.username =username;
this.passwd=passwd;
this.maxconn=maxconn;
}
/*将空閑連接配接傳回給連接配接池*/
public synchronized void returnConnection(Connection conn){
//将指定連接配接加到向量末尾
connections.addElement(conn);
//連接配接使用者減一
using--;
/*從連接配接池得到一個連接配接*/
public synchronized Connection getConnection(){
Connection conn = null; //Connection是一個類,
//connections是一個向量,用于存儲連接配接對象,它所存儲是的所有空閑狀态的可用連接配接
if (connections.size() > 0) {
//擷取連接配接清單的第一個連接配接
conn = (Connection) connections.elementAt(0);
connections.removeElementAt(0);//獲得一個連接配接,并将此連接配接從隊列中删除.
//如果此連接配接已關閉,剛繼續擷取,
try {
if (conn.isClosed())
conn = getConnection();
catch (Exception e) {
e.printStackTrace();
//如果實際使用的連接配接數小于最大連接配接數即有可用連接配接),就新增加一個連接配接
else if (maxconn == 0 || using < maxconn){
//如此時無可用連接配接(maxconn == 0)且連接配接數又未達到上限(using < maxconn)),就建立一個新連接配接
conn=newConnection();
//如果連接配接數已達到上限就傳回空指針
if (conn!=null){
using++;
return conn;
/*建立新的連接配接*/
public Connection newConnection(){
Connection conn=null;
try{
//加載驅動
Class.forName(drivername);
conn=DriverManager.getConnection(dbid,username,passwd);
}catch(Exception e){
return null;
/*關閉所有連接配接*/
public synchronized void closeConn(){
Enumeration allConnections=connections.elements();
while (allConnections.hasMoreElements()){
Connection conn=(Connection) allConnections.nextElement();
conn.close();
}catch(SQLException e){
connections.removeAllElements();
public class DBConnManager {
//連接配接池名清單
private Vector poolnames =new Vector();
//驅動程式名清單
private Vector drivernames=new Vector();
//資料庫辨別清單
private Vector dbids=new Vector();
//使用者名清單
private Vector usernames=new Vector();
//使用者密碼清單
private Vector passwds=new Vector();
//最大連接配接數清單
private Vector maxconns=new Vector();
//連接配接池隊列
private Hashtable connPools=new Hashtable();
public DBConnManager() {
//添加Access資料庫的連接配接資訊
poolnames.addElement("access");
drivernames.addElement("sun.jdbc.odbc.JdbcOdbcDriver");
dbids.addElement("jdbc
dbc:shopping");
usernames.addElement("");
passwds.addElement("");
maxconns.addElement("5");
//添加SQL Server2000資料庫的連接配接資訊
poolnames.addElement("sqlserver2000");
drivernames.addElement("com.microsoft.jdbc.sqlserver.SQLServerDriver");
dbids.addElement("jdbc:microsoft:sqlserver://localhost:1433;DatabserName=shopping");
//連接配接Mysql資料庫資訊
poolnames.addElement("mysql");
drivernames.addElement("org.gjt.mm.mysql.Driver");
dbids.addElement("jdbc:mysql://localhost/shopping");
//連接配接Oracle8i/9i資料庫
poolnames.addElement("oracle");
drivernames.addElement("oracle.jdbc.driver.OracleDriver");
racle:thin
localhost:1521:shopping");
//建立連接配接池
createPools();
/*将連接配接傳回給由指定的連接配接池*/
public void returnConnection(String name,Connection conn){
DBConnPool pool=(DBConnPool) connPools.get(name);
if (pool!=null)
{
pool.returnConnection(conn);
/*得到一個指定連接配接池中的連接配接*/
public Connection getConnection(String name){
return pool.getConnection();
public synchronized void closeConns(){
Enumeration allPools=connPools.elements();
while (allPools.hasMoreElements()){
DBConnPool pool=(DBConnPool) allPools.nextElement();
pool.closeConn();
/*建立連接配接池*/
private void createPools(){
for (int i=0;i<poolnames.size();i++)
String poolname=poolnames.elementAt(i).toString();
String drivername=drivernames.elementAt(i).toString();
String dbid=dbids.elementAt(i).toString();
String username=usernames.elementAt(i).toString();
String passwd=passwds.elementAt(i).toString();
int maxconn=0;
maxconn=Integer.parseInt(maxconns.elementAt(i).toString());
}catch (NumberFormatException e){
DBConnPool pool=new DBConnPool(poolname,drivername,dbid,username,
passwd,maxconn);
connPools.put(poolname,pool);
下面這個是首頁面.JSP檔案
<%@ page contentType="text/html; charset=GBK" %>
<%@ page import ="java.sql.*" %>
<jsp:useBean id="connManager" scope="application" class="mybean.DBConnManager" />
<html>
<head>
<title>
購物商城首頁
</title>
</head>
<body bgcolor="#B0C4DE">
<center><h1>歡迎通路本購物商城</h1></center>
<%
//Connection connA=connManager.getConnection("access");
Connection connS=connManager.getConnection("sqlserver2000");
if (connS==null)
%>
資料庫正忙,請稍後再通路
//Statement stmtA=connA.createStatement();
Statement stmtS=connS.createStatement();
String sql="select * from userinfo";
ResultSet rs=stmtS.executeQuery(sql);
while (rs.next())
<tr>
<td><%=rs.getString("username")%></td>
<td><%=rs.getString("userpass")%></td>
</tr>
rs.close();
stmtS.close();
connManager.returnConnection("sqlserver2000",connS);
</body>
</html>