package pandy.db; import java.io.*; import java.sql.Connection; import java.sql.DriverManager; import java.sql.Driver; import java.util.*; public class DBConnectionManager { static private DBConnectionManager instance; static private int clients; static String dbname="db"; public static String user=""; private Vector drivers = new Vector(); private PrintWriter log; private Hashtable pools = new Hashtable(); /** * ����Ψһʵ��������ǵ�һ�ε��ô˷������򴴽�ʵ�� * * * @return DBConnectionManager Ψһʵ�� */ static synchronized public DBConnectionManager getInstance() { if (instance == null) { instance = new DBConnectionManager(); } clients++; return instance; } /** * �����µĹ����ļ������������� */ static synchronized public DBConnectionManager getnewInstance(String newdbname) { dbname=newdbname; instance = new DBConnectionManager(); clients=0; return instance; } //����˽�к����Է�ֹ����������ñ���ʵ�� private DBConnectionManager() { init(); } /** * �����Ӷ��󷵻ظ�������ָ�������ӳ� * * * @param name �������ļ��ж�������ӳ����� * * * @param con ���Ӷ��� */ public void freeConnection(String name, Connection con) { DBConnectionPool pool = (DBConnectionPool) pools.get(name); if (pool != null) { pool.freeConnection(con); } } /** * ���һ�����ã����еģ����ӡ����û�п������ӣ�������������С��������������ƣ��򴴽������������� * * * @param name �������ļ��ж�������ӳ����� * * * @param Connecton �������ӻ�null */ public Connection getConnection(String name) { DBConnectionPool pool = (DBConnectionPool) pools.get(name); if (pool != null) { return pool.getConnection(); } return null; } /** * ���һ�����ã����еģ����ӡ����û�п������ӣ�������������С��������������ƣ��򴴽������������ӡ�������ָ����ʱ���ڵȴ������߳��ͷ����� * * * @param name �������ļ��ж�������ӳ����� * * * @param time �Ժ���Ƶĵȴ�ʱ�� * * * @return Connection �������ӻ�null */ public Connection getConnection(String name, long Time) { DBConnectionPool pool = (DBConnectionPool) pools.get(name); if (pool != null) { return pool.getConnection(Time); } return null; } //�չ��������ӣ��������������ע�� public synchronized void release() { //�ȴ�ֱ�����һ�������ͻ�������� if (--clients != 0) { return; } Enumeration allPools = pools.elements(); while (allPools.hasMoreElements()) { DBConnectionPool pool = (DBConnectionPool) allPools.nextElement(); pool.release(); } Enumeration allDrivers = drivers.elements(); while (allDrivers.hasMoreElements()) { Driver driver = (Driver) allDrivers.nextElement(); try { DriverManager.deregisterDriver(driver); System.out.println("����JDBC�����̵�ע��" + driver.getClass().getName() + "��ע��"); } catch (Exception e) { System.out.println("�޷���������JDBC���������ע��" + driver.getClass().getName()); } } } /** * ����ָ�����Դ������ӳ�ʵ�� * * * @param progs ���ӳ����� */ private void createPools(Properties props) { Enumeration propNames=props.propertyNames(); while(propNames.hasMoreElements()) { String name=(String)propNames.nextElement(); if(name.endsWith(".url")) { String poolName=name.substring(0,name.lastIndexOf(".")); String URL=props.getProperty(poolName+".url"); if(URL==null) { log("û��Ϊ���ӳ�"+poolName+"ָ��URL"); continue; } user=props.getProperty(poolName+".user"); String password=props.getProperty(poolName+".password"); String maxconn=props.getProperty(poolName+".maxconn","0"); int max; try { max=Integer.valueOf(maxconn).intValue(); } catch(NumberFormatException e) { log("�����������������ƣ�"+maxconn+"�����ӳأ�"+poolName); max=0; } DBConnectionPool pool=new DBConnectionPool(poolName,URL,user,password,max); pools.put(poolName,pool); } } } //��ȡ������ɳ�ʼ�� private void init() { Properties dbProps=new Properties(); try { File file = new File("properties/"+dbname+".properties"); InputStream is=new FileInputStream(file.getAbsolutePath()); dbProps.load(is); } catch(Exception e) { System.err.println("���ܶ�ȡ�����ļ���"+"��ȷ��db.properties��classpathָ����·����"); return; } String logFile=dbProps.getProperty("logfile","log.txt"); try { log=new PrintWriter(new FileWriter(logFile,true),true); } catch(IOException e) { System.err.println("�޷�����־�ļ���"+logFile); log=new PrintWriter(System.err); } String user=dbProps.getProperty("sqlserverbase.user"); loadDrivers(dbProps); createPools(dbProps); } /** * ���غ�ע������JDBC�������� * * * @param progs ���ӳ����� */ private void loadDrivers(Properties Props) { String driverClasses=Props.getProperty("driver"); StringTokenizer st=new StringTokenizer(driverClasses); while(st.hasMoreElements()) { String driverClassName=st.nextToken().trim(); try { Driver Driver =(Driver) Class.forName(driverClassName).newInstance(); DriverManager.registerDriver(Driver); drivers.addElement(Driver); log("�ɹ�ע��JDBC��������"+driverClassName); } catch(Exception e) { log("�޷�ע��JDBC��������"+driverClassName+",����"+e); } } } //���ı���Ϣд����־�ļ� private void log(String msg) { System.out.println(new Date() + ":" + msg); } //���ı���Ϣ���쳣д����־�ļ� private void log(Throwable e, String msg) { System.out.println(new Date() + ":����ԭ��" + e + ",������Ϣ��" + msg); } // ���ڲ��ඨ����һ�����ӳء����ܹ�����Ҫ�󴴽������ӣ�ֱ��Ԥ�������������Ϊֹ���ڷ������Ӹ��ͻ�����֮ǰ�����ܹ���֤���ӵ���Ч�� class DBConnectionPool { /** * �����µ����ӳ� * * @param name ���ӳ����� * @param URL ���ݿ��JDBC��URL * @param user ���ݿ��˺ţ���null * @param password ���룬��null * @param maxConn �����ӳ������������������ */ private int checkedOut; private Stack freeConnections = new Stack(); private int maxConn; private int Conncount = 0; private String name; private String password; private String URL; private String user; private String databaseUrl; public DBConnectionPool(String name, String url, String user, String password, int maxConn) { this.name = name; this.URL = url; this.user = user; this.password = password; this.maxConn = maxConn; for (int i = 0; i < maxConn; i++) { Connection con = newConnection(); checkedOut++; freeConnection(con); } } /** * ������ʹ�õ����ӷ��ظ����ӳ� * * * @param con �ͻ������ͷŵ����� */ public synchronized void freeConnection(Connection con) { freeConnections.push(con); checkedOut--; notifyAll(); System.out.println("�ɹ��ͷ�һ�����ӣ����ӳ��������С��" + Conncount + ",���У�" + freeConnections.size() + "�����ã�" + checkedOut); } //�����ӳػ��һ���������ӡ���û�п��е������ҵ�ǰ������С��������������ƣ��򴴽������ӡ���ԭ���Ǽ�Ϊ���õ����Ӳ�����Ч�����������ɾ����Ȼ��ݹ�����Լ��Գ����µĿ������ӡ� public synchronized Connection getConnection() { Connection con = null; if (freeConnections.size() > 0) { //��ȡ�����еĵ�һ���������� con = (Connection) freeConnections.pop(); try { if (con.isClosed()) { log("�����ӳ�" + name + "ɾ��һ����Ч����"); //�ݹ�����Լ��������ٴλ�ȡ�������� con = getConnection(); } } catch (Exception e) { log("�����ӳ�" + name + "ɾ��һ����Ч����"); //�ݹ�����Լ��������ٴλ�ȡ�������� con = getConnection(); } log("�����ӳ�" + name + "�ɹ���ȡһ������"); } else if (maxConn == 0 || checkedOut < maxConn) { con = newConnection(); } else { try { log("max using connect: [max:" + maxConn + "/all:" + Conncount + "/free:" + freeConnections.size() + "],wait ..."); wait(1000 * 10); return getConnection(); } catch (InterruptedException ie) { } } if (con != null) { checkedOut++; } return con; } //�����ӳػ�ȡ�������ӡ�����ָ���ͻ������ܹ��ȴ����ʱ�� //@param timeout���Ժ���Ƶĵȴ�ʱ������ public synchronized Connection getConnection(long timeout) { long startTime = new Date().getTime(); Connection con; while ((con = getConnection()) == null) { try { wait(timeout); } catch (InterruptedException e) { } if ((new Date().getTime() - startTime) >= timeout) { return null; } } return con; } //�ر��������� public synchronized void release() { Enumeration allConnections = freeConnections.elements(); while (allConnections.hasMoreElements()) { Connection con = (Connection) allConnections.nextElement(); try { con.close(); log("�ر����ӳ�" + name + "�е�һ������"); } catch (Exception e) { log(e, "�޷��ر����ӳ�" + name + "�е�һ������"); } } freeConnections.removeAllElements(); } //�����µ����� private Connection newConnection() { Connection con = null; try { if (user == null) { con = DriverManager.getConnection(URL); } else { con = DriverManager.getConnection(URL, user, password); } log("���ӳ�" + name + "����һ���µ�����"); Conncount++; } catch (Exception e) { log(e, "�޷���������URL������" + URL + "�û�����" + user + "���룺" + password); return null; } return con; } } }