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一个Oracle数据库链接的JavaBean实例

2019年11月05日 栏目:健康

public class OracleConnectionManager {private DBConnectionManager co

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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