一个Oracle数据库链接的JavaBean实例

　　public class OracleConnectionManager {

　　private DBConnectionManager connMgr;
　　private final String poolName="Oracle";
　　private Connection conn;

　　public OracleConnectionManager() {

　　String userID = "system";
　　String password = "manager";
　　String JDBCDriver = "oracle.jdbc.driver.OracleDriver";
　　String JDBCDriverType = "jdbc:oracle:thin";
　　String DBHost = "127.0.0.1";
　　String Port = "1521";
　　String SID="sid";
　　String url = JDBCDriverType+":@"+DBHost + ":" + Port + ":" +SID;

　　connMgr = DBConnectionManager.getInstance();
　　if (DBConnectionManager.clients == 1){
　　connMgr.init(poolName, JDBCDriver, url, userID, password);
　　connMgr.init("egongOracle", JDBCDriver, JDBCDriverType+":@110.7.6.22:1521:egong", "abcusername", "abcpasswd");

　　}
　　}

　　public Connection getConnection() {
　　return (conn=connMgr.getConnection(poolName));
　　}

　　public Connection getConnection(String newOracle) {
　　return (conn=connMgr.getConnection(newOracle));
　　}

　　public void freeConnection() {
　　connMgr.freeConnection(poolName,conn);
　　}

　　public void freeConnection(String newOracle) {
　　connMgr.freeConnection(newOracle,conn);
　　}

　　}

　　public class DBConnectionManager {
　　static private DBConnectionManager instance=null; // The single instance
　　static public int clients=0;

　　private Vector drivers = new Vector();
　　private PrintWriter log;
　　private Hashtable pools = new Hashtable();
　　private final int MAX_CONN = 1000;

　　/**
　　* Returns the single instance, creating one if it s the
　　* first time this method is called.
　　*
　　* @return DBConnectionManager The single instance.
　　*/
　　static synchronized public DBConnectionManager getInstance() {
　　if (instance == null) {
　　instance = new DBConnectionManager();
　　}
　　clients++;
　　return instance;
　　}

　　/**
　　* A private constructor since this is a Singleton
　　*/
　　private DBConnectionManager() {
　　// init();
　　}

　　/**
　　* Returns a connection to the named pool.
　　*
　　* @param name The pool name as defined in the properties file
　　* @param con The Connection
　　*/
　　public void freeConnection(String name, Connection con) {
　　DBConnectionPool pool = (DBConnectionPool) pools.get(name);
　　if (pool != null) {
　　pool.freeConnection(con);
　　}
　　}

　　/**
　　* Returns an open connection. If no one is available, and the max
　　* number of connections has not been reached, a new connection is
　　* created.
　　*
　　* @param name The pool name as defined in the properties file
　　* @return Connection The connection or null
　　*/
　　public Connection getConnection(String name) {
　　DBConnectionPool pool = (DBConnectionPool) pools.get(name);
　　if (pool != null) {
　　return pool.getConnection();
　　}
　　return null;
　　}

　　/**
　　* Returns an open connection. If no one is available, and the max
　　* number of connections has not been reached, a new connection is
　　* created. If the max number has been reached, waits until one
　　* is available or the specified time has elapsed.
　　*
　　* @param name The pool name as defined in the properties file
　　* @param time The number of milliseconds to wait
　　* @return Connection The connection or null
　　*/
　　public Connection getConnection(String name, long time) {
　　DBConnectionPool pool = (DBConnectionPool) pools.get(name);
　　if (pool != null) {
　　return pool.getConnection(time);
　　}
　　return null;
　　}

　　/**
　　* Closes all open connections and dereGISters all drivers.
　　*/
　　public synchronized void release() {
　　// Wait until called by the last client
　　if (--clients != 0) {
　　return;
　　}