c3p0连接池

突然想用一下c3p0连接池，在网上找了一下，要么根本不能用，要么就是达不到自己的要求。
不过后来想起以前有人写过这样的一个类，于是拿出来试了一下，果然能用，而且功能也非常完善。

环境：
eclipse3.5
mysql-connector-java-5.1.7-bin.jar
c3p0-0.9.1.2.jar
commons-logging-1.1.1.jar


JAVA类代码如下：

public class ConnectionPool {

	public static void cleanUp(Connection con) {
		_instance._cleanUp(con);
	}
	public static void cleanUp(Connection con, Statement s) {
		_instance._cleanUp(con, s);
	}
	public static void cleanUp(Connection con, Statement s, ResultSet rs) {
		_instance._cleanUp(con, s, rs);
	}
	public static void destroy() throws SQLException {
		_instance._destroy();
	}

	public static Connection getConnection() throws SQLException {
		return _instance._getConnection();
	}

	public static Properties getProperties() {
		return _instance._props;
	}

	private ConnectionPool() {
		try {

			// Properties

			ClassLoader classLoader = getClass().getClassLoader();

			_props = new Properties();

			_props.load(classLoader.getResourceAsStream(
				"connection-pool.properties"));

			_props.list(System.out);

			// Pooled data source

			String driverClass = _props.getProperty("driver.class");
			String jdbcUrl = _props.getProperty("jdbc.url");
			String user = _props.getProperty("user");
			String password = _props.getProperty("password");

			int minPoolSize = 5;

			try {
				minPoolSize = Integer.parseInt(
					_props.getProperty("min.pool.size"));
			}
			catch (Exception e) {
			}

			int maxPoolSize = 5;

			try {
				maxPoolSize = Integer.parseInt(
					_props.getProperty("max.pool.size"));
			}
			catch (Exception e) {
			}

			int acquireIncrement = 5;

			try {
				acquireIncrement = Integer.parseInt(
					_props.getProperty("acquire.increment"));
			}
			catch (Exception e) {
			}

			_cpds = new ComboPooledDataSource();

			_cpds.setDriverClass(driverClass);
			_cpds.setJdbcUrl(jdbcUrl);
			_cpds.setUser(user);
			_cpds.setPassword(password);

			_cpds.setMinPoolSize(minPoolSize);
			_cpds.setMaxPoolSize(maxPoolSize);
			_cpds.setAcquireIncrement(acquireIncrement);
		}
		catch (Exception e) {
			_log.error(e);
		}
	}

	private void _cleanUp(Connection con) {
		_cleanUp(con, null, null);
	}

	private void _cleanUp(Connection con, Statement s) {
		_cleanUp(con, s, null);
	}

	private void _cleanUp(Connection con, Statement s, ResultSet rs) {
		try {
			if (rs != null) {
				rs.close();
			}
		}
		catch (SQLException sqle) {
			_log.error(sqle);
		}

		try {
			if (s != null) {
				s.close();
			}
		}
		catch (SQLException sqle) {
			_log.error(sqle);
		}

		try {
			if (con != null) {
				con.close();
			}
		}
		catch (SQLException sqle) {
			_log.error(sqle);
		}
	}

	private void _destroy() throws SQLException {
		DataSources.destroy(_cpds);
	}

	private Connection _getConnection() throws SQLException {
		return _cpds.getConnection();
	}

	private static Log _log = LogFactory.getLog(ConnectionPool.class);

	private static ConnectionPool _instance = new ConnectionPool();

	private Properties _props;
	private ComboPooledDataSource _cpds;

}

当然还得在包的根目录下建一个配置文件connection-pool.properties，内容如下：

driver.class=com.mysql.jdbc.Driver
jdbc.url=
user=
password=

min.pool.size=5
max.pool.size=20
acquire.increment=5

在配置文件中填上相应的值，以后就可以直接使用此类获得数据库连接了。需要注意的是用完之后要手动关闭连接。