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;
}

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);
log("Deregistered JDBC driver " + driver.getClass().getName());
}
catch (SQLException e) {
log(e, "Can´t deregister JDBC driver: " + driver.getClass().getName());
}
}
log.close();
}

/**
* Creates instances of DBConnectionPool based on the properties.
* A DBConnectionPool can be defined with the following properties:
* <PRE>
* <poolname>.url The JDBC URL for the database
* <poolname>.user A database user (optional)
* <poolname>.password A database user password (if user specified)
* <poolname>.maxconn The maximal number of connections (optional)
* </PRE>
*
* @param props The connection pool properties
*/
private void createPools(String poolName, String url, String user, String password, int max) {
/*
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("No URL specified for " + poolName);
continue;
}
String 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("Invalid maxconn value " + maxconn + " for " + poolName);
max = 0;
}
DBConnectionPool pool =
new DBConnectionPool(poolName, url, user, password, max);
pools.put(poolName, pool);
log("Initialized pool " + poolName);
}
}
*/
DBConnectionPool pool =
new DBConnectionPool(poolName, url, user, password, max);
pools.put(poolName, pool);
log("Initialized pool " + poolName);
}

public void init(String poolName, String driver, String url, String user, String passwd) {
init(poolName, driver, url, user, passwd, MAX_CONN);
}

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