c3p0连接mysql不关闭连接

Connection conn = null;
try {
    conn = dataSource.getConnection();
    // 执行数据库操作
} catch (SQLException e) {
    e.printStackTrace();
} finally {
    if (conn != null) {
        try {
            conn.close();
        } catch (SQLException e) {
            e.printStackTrace();
        }
    }
}

<bean id="dataSource" class="com.mchange.v2.c3p0.ComboPooledDataSource" destroy-method="close">
    <property name="driverClass" value="com.mysql.jdbc.Driver"/>
    <property name="jdbcUrl" value="jdbc:mysql://localhost:3306/mydb"/>
    <property name="user" value="username"/>
    <property name="password" value="password"/>
    <property name="maxIdleTime" value="60"/>
    <property name="maxStatements" value="0"/>
</bean>

Connection conn = null;
try {
    conn = dataSource.getConnection();
    conn.setAutoCommit(false);
    // 执行数据库操作
    conn.commit();
} catch (SQLException e) {
    if (conn != null) {
        try {
            conn.rollback();
        } catch (SQLException ex) {
            ex.printStackTrace();
        }
    }
    e.printStackTrace();
} finally {
    if (conn != null) {
        try {
            conn.close();
        } catch (SQLException e) {
            e.printStackTrace();
        }
    }
}