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2006年3月 (4)

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[收藏]數據庫連接池Java實現小結

Posted on 2006-03-20 23:24 ikingqu 閱讀(268) 評論(0) 編輯收藏所屬分類: DataBase

??因為工作需要要使用到連接池，所以拜讀了互聯網上眾多前輩的文章，學了不少經驗，這里想做一個小結，加上自己的想法和在一起，希望能給大家一些幫助。

目的：

消除數據庫頻繁連接帶來的開銷和瓶頸。

解決方案：

不過多的限制用戶的使用，既不能太多的要求用戶按規定的方法得到和使用數據庫連

盡量保持用戶的習慣

目前的很多方法都是要求用戶只能按規定方法使用連接，不能使用直接關閉數據連接的方法。解決辦法就是使用代理類，來中間解決。可以參考http://www-900.ibm.com/developerWorks/cn/java/l-connpoolproxy/index.shtml

能維護連接的正常狀態

因為針對數據庫連接創建的資源，如果不能及時的釋放，就會影響下一次數據連接的使用。例如在sql 2k中，一個連接不同創建多條Statement否則操作時會有數據連接占線的異常，所以必須在歸還連接以后釋放這些資源。


???//判斷是使用了createStatement語句
???if (CREATESTATE.equals(method.getName()))
???{
????obj = method.invoke(conn, args);
????statRef = (Statement)obj;//記錄語句
????return obj;
???}

???//判斷是否調用了close的方法，如果調用close方法則把連接置為無用狀態
???if(CLOSE.equals(method.getName()))
???{
????//設置不使用標志
????setIsFree(false);
????//檢查是否有后續工作，清除該連接無用資源
????if (statRef != null)
?????statRef.close();
????if (prestatRef != null)
?????prestatRef.close();
????return null;
???}

正確保護類不被違例使用

一個考慮就是不能讓用戶隨便使用代理類，而只能自己使用，一個就是用內部私有類，一個就是使用只有指定類才能調用的標志。我的實現就是采用后者。

?/**
? * 創建連接的工廠，只能讓工廠調用
? * @param factory 要調用工廠，并且一定被正確初始化
? * @param param 連接參數
? * @return 連接
? */
?static public _Connection getConnection(ConnectionFactory factory, ConnectionParam param)
?{
??if (factory.isCreate())//判斷是否正確初始化的工廠
??{
???_Connection _conn = new _Connection(param);
???return _conn;
??}
??else
???return null;
?}

提供良好的用戶接口，簡單實用

使用靜態方法創建工廠，然后來得到連接，使用完全和普通的Connection方法一樣，沒有限制。同時為了方便，設置了連接參數類和工廠參數類。

?ConnectionParam param = new ConnectionParam(driver,url,user,password);
??ConnectionFactory cf = null;//new ConnectionFactory(param, new FactoryParam());
??try{
???cf = new ConnectionFactory(param,new FactoryParam());
???Connection conn1 = cf.getFreeConnection();
???Connection conn2 = cf.getFreeConnection();
???Connection conn3 = cf.getFreeConnection();
???Statement stmt = conn1.createStatement();
???ResultSet rs = stmt.executeQuery("select * from requests");
???if (rs.next())
???{
????System.out.println("conn1 y");??
???}
???else
???{
????System.out.println("conn1 n");??
???}?
???stmt.close();
???conn1.close();??

為了實現連接池的正常運作，使用了單態模

?/**
? * 使用指定的參數創建一個連接池
? */
?public ConnectionFactory(ConnectionParam param, FactoryParam fparam)
??throws SQLException 
?{
??//不允許參數為空
??if ((param == null)||(fparam == null))
???throw new SQLException("ConnectionParam和FactoryParam不能為空");
??if (m_instance == null)
??{
???synchronized(ConnectionFactory.class){
????if (m_instance == null)
????{
?????//new instance
?????//參數定制
?????m_instance = new ConnectionFactory();
?????m_instance.connparam = param;
?????m_instance.MaxConnectionCount = fparam.getMaxConn();
?????m_instance.MinConnectionCount = fparam.getMinConn();
?????m_instance.ManageType = fparam.getType();
?????m_instance.isflag = true;
?????//初始化，創建MinConnectionCount個連接
?????System.out.println("connection factory 創建！");
?????try{
??????for (int i=0; i < m_instance.MinConnectionCount; i++)
??????{
???????_Connection _conn = _Connection.getConnection(m_instance, m_instance.connparam);
???????if (_conn == null) continue;
???????System.out.println("connection創建");
???????m_instance.FreeConnectionPool.add(_conn);//加入空閑連接池
???????m_instance.current_conn_count ++;
???????//標志是否支持事務
???????m_instance.supportTransaction = _conn.isSupportTransaction();????
??????}
?????}
?????catch(Exception e)
?????{
??????e.printStackTrace();
?????}
?????//根據策略判斷是否需要查詢
?????if (m_instance.ManageType != 0)
?????{
??????Thread t = new Thread(new FactoryMangeThread(m_instance));
??????t.start();
?????}?
????}
???}
??}
?}
?

連接池的管理

對于連接池的管理，我是設想使用靜態管理和動態管理兩種策略，設置了最大限制，和恒定的連接數。使用了2個池，一個空閑池，一個使用池。靜態就是使用的時候發現空閑連接不夠再去檢查。動態就是使用了一個線程定時檢查。

?//根據策略判斷是否需要查詢
?????if (m_instance.ManageType != 0)
?????{
??????Thread t = new Thread(new FactoryMangeThread(m_instance));
??????t.start();
?????}

?//連接池調度線程
public class FactoryMangeThread implements Runnable {
?ConnectionFactory cf = null;
?long delay = 1000;
?public FactoryMangeThread(ConnectionFactory obj)
?{
??cf = obj;
?}
?/* (non-Javadoc)
? * @see java.lang.Runnable#run()
? */
?public void run() {
??while(true){
???try{
????Thread.sleep(delay);
???}
???catch(InterruptedException e){}
???System.out.println("eeeee");
???//判斷是否已經關閉了工廠，那就退出監聽
???if (cf.isCreate())
????cf.schedule();
???else
????System.exit(1);
??}
?}
}

最后給出完整的源代碼：

_Connectio.java

package scut.ailab.connectionpool;

import java.lang.reflect.*;
import java.sql.*;

/**
?* @author youyongming
?* 定義數據庫連接的代理類
?*/
public class _Connection implements InvocationHandler {
?//定義連接
?private Connection conn = null;
?//定義監控連接創建的語句
?private Statement statRef = null;
?private PreparedStatement prestatRef = null;
?//是否支持事務標志
?private boolean supportTransaction = false;
?//數據庫的忙狀態
?private boolean isFree = false;
?//最后一次訪問時間
?long lastAccessTime = 0;
?//定義要接管的函數的名字
?String CREATESTATE = "createStatement";
?String CLOSE = "close";
?String PREPARESTATEMENT = "prepareStatement";
?String COMMIT = "commit";
?String ROLLBACK = "rollback";

?/**
? * 構造函數，采用私有，防止被直接創建
? * @param param 連接參數
? */
?private _Connection(ConnectionParam param) {
??//記錄日至
??
??try{
???//創建連接
???Class.forName(param.getDriver()).newInstance();
???conn = DriverManager.getConnection(param.getUrl(),param.getUser(), param.getPassword());???
???DatabaseMetaData dm = null;
???dm = conn.getMetaData();
???//判斷是否支持事務
???supportTransaction = dm.supportsTransactions();
??}
??catch(Exception e)
??{
???e.printStackTrace();
??}
?}


?/* (non-Javadoc)
? * @see java.lang.reflect.InvocationHandler#invoke(java.lang.Object, java.lang.reflect.Method, java.lang.Object[])
? */
?public Object invoke(Object proxy, Method method, Object[] args)
??throws Throwable {
???Object obj = null;
???//判斷是否調用了close的方法，如果調用close方法則把連接置為無用狀態
???if(CLOSE.equals(method.getName()))
???{
????//設置不使用標志
????setIsFree(false);
????//檢查是否有后續工作，清除該連接無用資源
????if (statRef != null)
?????statRef.close();
????if (prestatRef != null)
?????prestatRef.close();
????return null;
???}
???//判斷是使用了createStatement語句
???if (CREATESTATE.equals(method.getName()))
???{
????obj = method.invoke(conn, args);
????statRef = (Statement)obj;//記錄語句
????return obj;
???}
???//判斷是使用了prepareStatement語句
???if (PREPARESTATEMENT.equals(method.getName()))
???{
????obj = method.invoke(conn, args);
????prestatRef = (PreparedStatement)obj;
????return obj;
???}
???//如果不支持事務，就不執行該事物的代碼
???if ((COMMIT.equals(method.getName())||ROLLBACK.equals(method.getName())) && (!isSupportTransaction()))
????return null;???
???obj = method.invoke(conn, args);?
???//設置最后一次訪問時間，以便及時清除超時的連接
???lastAccessTime = System.currentTimeMillis();
???return obj;
?}

?/**
? * 創建連接的工廠，只能讓工廠調用
? * @param factory 要調用工廠，并且一定被正確初始化
? * @param param 連接參數
? * @return 連接
? */
?static public _Connection getConnection(ConnectionFactory factory, ConnectionParam param)
?{
??if (factory.isCreate())//判斷是否正確初始化的工廠
??{
???_Connection _conn = new _Connection(param);
???return _conn;
??}
??else
???return null;
?}
?
?public Connection getFreeConnection() {
??//返回數據庫連接conn的接管類，以便截住close方法
??Connection conn2 = (Connection)Proxy.newProxyInstance(
???conn.getClass().getClassLoader(),
???conn.getClass().getInterfaces(),this);
??return conn2;
?}

?/**
? * 該方法真正的關閉了數據庫的連接
? * @throws SQLException
? */
?void close() throws SQLException{
??//由于類屬性conn是沒有被接管的連接，因此一旦調用close方法后就直接關閉連接
??conn.close();
?}
???
?public void setIsFree(boolean value)
?{
??isFree = value;
?}
?
?public boolean isFree() {
??return isFree;
?}?
?/**
? * 判斷是否支持事務
? * @return boolean
? */
?public boolean isSupportTransaction() {
??return supportTransaction;
?}?
}

ConnectionFactory.java

?package scut.ailab.connectionpool;

/**
?* @author youyongming
?*
?*/
import java.util.LinkedHashSet;
import java.sql.*;
import java.util.Iterator;

public class ConnectionFactory {
?private static ConnectionFactory m_instance = null;
?//在使用的連接池
?private LinkedHashSet ConnectionPool = null;
?//空閑連接池
?private LinkedHashSet FreeConnectionPool = null;
?//最大連接數
?private int MaxConnectionCount = 4;
?//最小連接數
?private int MinConnectionCount = 2;
?//當前連接數
?private int current_conn_count = 0;
?//連接參數
?private ConnectionParam connparam = null;
?//是否創建工廠的標志
?private boolean isflag = false;
?//是否支持事務
?private boolean supportTransaction = false;
?//定義管理策略
?private int ManageType = 0;

?private ConnectionFactory()?{
??ConnectionPool = new LinkedHashSet();
??FreeConnectionPool = new LinkedHashSet();
?}
?
?/**
? * 使用指定的參數創建一個連接池
? */
?public ConnectionFactory(ConnectionParam param, FactoryParam fparam)
??throws SQLException 
?{
??//不允許參數為空
??if ((param == null)||(fparam == null))
???throw new SQLException("ConnectionParam和FactoryParam不能為空");
??if (m_instance == null)
??{
???synchronized(ConnectionFactory.class){
????if (m_instance == null)
????{
?????//new instance
?????//參數定制
?????m_instance = new ConnectionFactory();
?????m_instance.connparam = param;
?????m_instance.MaxConnectionCount = fparam.getMaxConn();
?????m_instance.MinConnectionCount = fparam.getMinConn();
?????m_instance.ManageType = fparam.getType();
?????m_instance.isflag = true;
?????//初始化，創建MinConnectionCount個連接
?????System.out.println("connection factory 創建！");
?????try{
??????for (int i=0; i < m_instance.MinConnectionCount; i++)
??????{
???????_Connection _conn = _Connection.getConnection(m_instance, m_instance.connparam);
???????if (_conn == null) continue;
???????System.out.println("connection創建");
???????m_instance.FreeConnectionPool.add(_conn);//加入空閑連接池
???????m_instance.current_conn_count ++;
???????//標志是否支持事務
???????m_instance.supportTransaction = _conn.isSupportTransaction();????
??????}
?????}
?????catch(Exception e)
?????{
??????e.printStackTrace();
?????}
?????//根據策略判斷是否需要查詢
?????if (m_instance.ManageType != 0)
?????{
??????Thread t = new Thread(new FactoryMangeThread(m_instance));
??????t.start();
?????}?
????}
???}
??}
?}
?
?/**
? * 標志工廠是否已經創建
? * @return boolean
? */?
?public boolean isCreate()
?{
??return m_instance.isflag;
?}
?
?/**
? * 從連接池中取一個空閑的連接
? * @return Connection
? * @throws SQLException
? */
?public synchronized Connection getFreeConnection() 
??throws SQLException
?{
??Connection conn = null;
??//獲取空閑連接
??Iterator iter = m_instance.FreeConnectionPool.iterator();
??while(iter.hasNext()){
???_Connection _conn = (_Connection)iter.next();
???//找到未用連接
???if(!_conn.isFree()){
????conn = _conn.getFreeConnection();
????_conn.setIsFree(true);
????//移出空閑區
????m_instance.FreeConnectionPool.remove(_conn);
????//加入連接池?
????m_instance.ConnectionPool.add(_conn);???
????break;
???}
??}
??//檢查空閑池是否為空
??if (m_instance.FreeConnectionPool.isEmpty())
??{
???//再檢查是否能夠分配
???if (m_instance.current_conn_count < m_instance.MaxConnectionCount)
???{
???//新建連接到空閑連接池
????int newcount = 0 ;
????//取得要建立的數目
????if (m_instance.MaxConnectionCount - m_instance.current_conn_count >=m_instance.MinConnectionCount)
????{
?????newcount = m_instance.MinConnectionCount;
????}
????else
????{
?????newcount = m_instance.MaxConnectionCount - m_instance.current_conn_count;
????}
????//創建連接
????for (int i=0;i <newcount; i++)
????{
?????_Connection _conn = _Connection.getConnection(m_instance, m_instance.connparam);
?????m_instance.FreeConnectionPool.add(_conn);
?????m_instance.current_conn_count ++;
????}
???}
???else
???{//如果不能新建，檢查是否有已經歸還的連接
????iter = m_instance.ConnectionPool.iterator();
????while(iter.hasNext()){
?????_Connection _conn = (_Connection)iter.next();
?????if(!_conn.isFree()){
??????conn = _conn.getFreeConnection();
??????_conn.setIsFree(false);
??????m_instance.ConnectionPool.remove(_conn);?
??????m_instance.FreeConnectionPool.add(_conn);???
??????break;
?????}
????}????
???}
??}//if (FreeConnectionPool.isEmpty())
?//再次檢查是否能分配連接
??if(conn == null){
???iter = m_instance.FreeConnectionPool.iterator();
???while(iter.hasNext()){
????_Connection _conn = (_Connection)iter.next();
????if(!_conn.isFree()){
?????conn = _conn.getFreeConnection();
?????_conn.setIsFree(true);
?????m_instance.FreeConnectionPool.remove(_conn);?
?????m_instance.ConnectionPool.add(_conn);???
?????break;
????}
???}
???if(conn == null)//如果不能則說明無連接可用
????throw new SQLException("沒有可用的數據庫連接");
??}
??System.out.println("get connection");
??return conn;
?}
?
?/**
? * 關閉該連接池中的所有數據庫連接
? * @throws SQLException
? */
?public synchronized void close() throws SQLException
?{
??this.isflag = false;
??SQLException excp = null;
??//關閉空閑池
??Iterator iter = m_instance.FreeConnectionPool.iterator();
??while(iter.hasNext()){
???try{
????((_Connection)iter.next()).close();
????System.out.println("close connection:free");
????m_instance.current_conn_count --;
???}catch(Exception e){
????if(e instanceof SQLException)
?????excp = (SQLException)e;
???}
??}
??//關閉在使用的連接池
??iter = m_instance.ConnectionPool.iterator();
??while(iter.hasNext()){
???try{
????((_Connection)iter.next()).close();
????System.out.println("close connection:inused");
????m_instance.current_conn_count --;
???}catch(Exception e){
????if(e instanceof SQLException)
?????excp = (SQLException)e;
???}
??}??
??if(excp != null)
???throw excp;
?}?
?
?/**
? * 返回是否支持事務
? * @return boolean
? */
?public boolean isSupportTransaction() {
??return m_instance.supportTransaction;
?}??
?/**
? * 連接池調度管理
? *
? */
?public void schedule()
?{
??Connection conn = null;
??//再檢查是否能夠分配
??Iterator iter = null;
??//檢查是否有已經歸還的連接
??{
???iter = m_instance.ConnectionPool.iterator();
???while(iter.hasNext()){
????_Connection _conn = (_Connection)iter.next();
????if(!_conn.isFree()){
?????conn = _conn.getFreeConnection();
?????_conn.setIsFree(false);
?????m_instance.ConnectionPool.remove(_conn);?
?????m_instance.FreeConnectionPool.add(_conn);???
?????break;
????}
???}????
??}
??if (m_instance.current_conn_count < m_instance.MaxConnectionCount)
??{
???//新建連接到空閑連接池
???int newcount = 0 ;
???//取得要建立的數目
???if (m_instance.MaxConnectionCount - m_instance.current_conn_count >=m_instance.MinConnectionCount)
???{
????newcount = m_instance.MinConnectionCount;
???}
???else
???{
????newcount = m_instance.MaxConnectionCount - m_instance.current_conn_count;
???}
???//創建連接
???for (int i=0;i <newcount; i++)
???{
????_Connection _conn = _Connection.getConnection(m_instance, m_instance.connparam);
????m_instance.FreeConnectionPool.add(_conn);
????m_instance.current_conn_count ++;
???}
??}
?}
}

ConnectionParam.java

?package scut.ailab.connectionpool;

import java.io.Serializable;

/**
?* @author youyongming
?* 實現數據庫連接的參數類
?*/
public class ConnectionParam implements Serializable {
?private String driver;????//數據庫驅動程序
?private String url;???//數據連接的URL
?private String user;????//數據庫用戶名
?private String password;???//數據庫密碼
?
?/**
? * 唯一的構造函數，需要指定連接的四個必要參數
? * @param driver?數據驅動
? * @param url??數據庫連接url
? * @param user??用戶名
? * @param password?密碼
? */
?public ConnectionParam(String driver,String url,String user,String password)
?{
??this.driver = driver;
??this.url = url;
??this.user = user;
??this.password = password;
?}

?public String getDriver() {
??return driver;
?}

?public String getPassword() {
??return password;
?}

?public String getUrl() {
??return url;
?}

?public String getUser() {
??return user;
?}

?public void setDriver(String driver) {
??this.driver = driver;
?}

?public void setPassword(String password) {
??this.password = password;
?}

?public void setUrl(String url) {
??this.url = url;
?}

?public void setUser(String user) {
??this.user = user;
?}

?/**
? * @see java.lang.Object#clone()
? */
?public Object clone(){
??ConnectionParam param = new ConnectionParam(driver,url,user,password);
??return param;
?}

?/**
? * @see java.lang.Object#equals(java.lang.Object)
? */
?public boolean equals(Object obj) {
??if(obj instanceof ConnectionParam){
???ConnectionParam param = (ConnectionParam)obj;
???return ((driver.compareToIgnoreCase(param.getDriver()) == 0)&&
???(url.compareToIgnoreCase(param.getUrl()) == 0)&&
???(user.compareToIgnoreCase(param.getUser()) == 0)&&
???(password.compareToIgnoreCase(param.getPassword()) == 0));
??}
??return false;
?}
}

FactoryMangeThread.java

?/*
?* Created on 2003-5-13
?*
?* To change the template for this generated file go to
?* Window>Preferences>Java>Code Generation>Code and Comments
?*/
package scut.ailab.connectionpool;

/**
?* @author youyongming
?*
?*/
//連接池調度線程
public class FactoryMangeThread implements Runnable {
?ConnectionFactory cf = null;
?long delay = 1000;
?public FactoryMangeThread(ConnectionFactory obj)
?{
??cf = obj;
?}
?/* (non-Javadoc)
? * @see java.lang.Runnable#run()
? */
?public void run() {
??while(true){
???try{
????Thread.sleep(delay);
???}
???catch(InterruptedException e){}
???System.out.println("eeeee");
???//判斷是否已經關閉了工廠，那就退出監聽
???if (cf.isCreate())
????cf.schedule();
???else
????System.exit(1);
??}
?}
}

FactoryParam.java

?/*
?* Created on 2003-5-13
?*
?* To change the template for this generated file go to
?* Window>Preferences>Java>Code Generation>Code and Comments
?*/
package scut.ailab.connectionpool;

/**
?* @author youyongming
?*
?*/
//連接池工廠參數
public class FactoryParam {
?//最大連接數
?private int MaxConnectionCount = 4;
?//最小連接數
?private int MinConnectionCount = 2; 
?//回收策略
?private int ManageType = 0;
?
?public FactoryParam()?{
?}
?
?/**
? * 構造連接池工廠參數的對象
? * @param max?最大連接數
? * @param min?最小連接數
? * @param type?管理策略
? */
?public FactoryParam(int max, int min, int type)
?{
??this.ManageType = type;
??this.MaxConnectionCount = max;
??this.MinConnectionCount = min;
?}
?
?/**
? * 設置最大的連接數
? * @param value
? */
?public void setMaxConn(int value)
?{
??this.MaxConnectionCount = value;
?}
?/**
? * 獲取最大連接數
? * @return
? */
?public int getMaxConn()
?{
??return this.MaxConnectionCount;
?}
?/**
? * 設置最小連接數
? * @param value
? */
?public void setMinConn(int value)
?{
??this.MinConnectionCount = value;
?}
?/**
? * 獲取最小連接數
? * @return
? */
?public int getMinConn()
?{
??return this.MinConnectionCount;
?}
?public int getType()
?{
??return this.ManageType;
?}
}

testmypool.java

?/*
?* Created on 2003-5-13
?*
?* To change the template for this generated file go to
?* Window>Preferences>Java>Code Generation>Code and Comments
?*/
package scut.ailab.connectionpool;

/**
?* @author youyongming
?*
?*/
import java.sql.*;

public class testmypool {

?public void test1()
?{
??String user = "DevTeam";
??String password = "DevTeam";
??String driver = "sun.jdbc.odbc.JdbcOdbcDriver";
??String url = "jdbc:odbc:gfqh2";
??ConnectionParam param = new ConnectionParam(driver,url,user,password);
??ConnectionFactory cf = null;//new ConnectionFactory(param, new FactoryParam());
??try{
???cf = new ConnectionFactory(param,new FactoryParam());
???Connection conn1 = cf.getFreeConnection();
???Connection conn2 = cf.getFreeConnection();
???Connection conn3 = cf.getFreeConnection();
???Statement stmt = conn1.createStatement();
???ResultSet rs = stmt.executeQuery("select * from requests");
???if (rs.next())
???{
????System.out.println("conn1 y");??
???}
???else
???{
????System.out.println("conn1 n");??
???}?
???stmt.close();
???conn1.close();??
???Connection conn4 = cf.getFreeConnection();
???Connection conn5 = cf.getFreeConnection();
???stmt = conn5.createStatement();
???rs = stmt.executeQuery("select * from requests");
???if (rs.next())
???{
????System.out.println("conn5 y");??
???}
???else
???{
????System.out.println("conn5 n");??
???}?
???conn2.close();
???conn3.close();
???conn4.close();
???conn5.close();
???}
??catch(Exception e)
??{
???e.printStackTrace();
??}
??finally{
???try{
????cf.close();
???}
???catch(Exception e)
???{
????e.printStackTrace();
???}
??}?
?}
?public static void main(String[] args) {
??String user = "DevTeam";
??String password = "DevTeam";
??String driver = "sun.jdbc.odbc.JdbcOdbcDriver";
??String url = "jdbc:odbc:gfqh2";
??ConnectionParam param = new ConnectionParam(driver,url,user,password);
??ConnectionFactory cf = null;//new ConnectionFactory(param,new FactoryParam());
??try{
???cf = new ConnectionFactory(param,new FactoryParam());
???ConnectionFactory cf1= new ConnectionFactory(param,new FactoryParam());
???Connection conn1 = null;
???long time = System.currentTimeMillis();
???for (int i=0; i <10;i++)
???{
????conn1 = cf.getFreeConnection();
????Statement stmt = conn1.createStatement();
????ResultSet rs = stmt.executeQuery("select * from requests");
????if (rs.next())
????{
?????System.out.println("conn1 y");??
????}
????else
????{
?????System.out.println("conn1 n");??
????}?
????conn1.close();??
???}
???System.out.println("pool:" + (System.currentTimeMillis()-time));
???time = System.currentTimeMillis();
???Class.forName(param.getDriver()).newInstance();
???for (int i=0; i <10;i++)
???{
????conn1 = DriverManager.getConnection(param.getUrl(),param.getUser(), param.getPassword());???
????Statement stmt = conn1.createStatement();
????ResultSet rs = stmt.executeQuery("select * from requests");
????if (rs.next())
????{
?????System.out.println("conn1 y");??
????}
????else
????{
?????System.out.println("conn1 n");??
????}?
????conn1.close();??
???}???
???System.out.println("no pool:" + (System.currentTimeMillis()-time));
??}
??catch(Exception e)
??{
???e.printStackTrace();
??}
??finally{
???try{
????cf.close();
???}
???catch(Exception e)
???{
????e.printStackTrace();
???}
??}
?}
}

原文鏈接:http://www.jaron.cn/chs_db/16/2003-09/20030916110224-101181.html

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