C3P0连接池详细配置

我们许多人有的是使用的时应用服务器自带的数据连接池，有的是使用dbcp，c3p0，proxypool等数据库连接池，以前我直接使用hibernate的时候，这些连接池的配置按照hibernate的文档配置没有问题，这段时间配置的是c3p0的JDBC数据库连接池。 多话不说了，代码贴出来，希望对大家有所帮助。

定义一个接口，里面三个抽象方法：
public interface IConnectionProvider {
public void configure(Properties props);
public Connection getConnection() throws SQLException;
public void closeConnection(Connection conn) throws SQLException;
public void close();
}

实现上面的三个接口，进行C3P0配置
public class C3P0ConnectionProvider implements IConnectionProvider {
    private DataSource ds;

    private static final Log log = LogFactory.getLog(C3P0ConnectionProvider.class);

    public void configure(Properties props) {
        String jdbcDriverClass = props.getProperty(Constant.JDBC_DRIVER);//JDBC驱动
        try {
            Class.forName(jdbcDriverClass);
            String username = props.getProperty(Constant.JDBC_USERNAME);//jdbc连接用户名
            String password = props.getProperty(Constant.JDBC_PASSWORD);//jdbc连接密码
            String url = props.getProperty(Constant.JDBC_URL);//jdbc连接url字符串
            DataSource ds_unpooled = DataSources.unpooledDataSource(url, username, password);
           
            Properties overrides = new Properties();
            String minSize = props.getProperty(Constant.JDBC_MINPOOLSIZE);
            if (minSize == null || minSize.length() == 0) {
                minSize = "10";
            }
            String maxSize = props.getProperty(Constant.JDBC_MAXPOOLSIZE);
            if (maxSize == null || maxSize.length() == 0) {
                maxSize = "30";
            }

            overrides.put("minPoolSize", Integer.parseInt(minSize));
            overrides.put("maxStatements", "200");
            overrides.put("maxPoolSize", Integer.parseInt(maxSize));

            ds = DataSources.pooledDataSource(ds_unpooled, overrides);
        } catch (Exception e) {
            log.error("jdbc driver class not found ,the driver class is " + jdbcDriverClass, e);
        }
    }

    public Connection getConnection() throws SQLException {
        final Connection conn = ds.getConnection();
        return conn;
    }

    public void closeConnection(Connection conn) throws SQLException {
        conn.close();
    }

    public void close() {
        try {
            DataSources.destroy(ds);
        } catch (SQLException sqle) {
            log.warn("could not destroy C3P0 connection pool", sqle);
        }
    }

}