//连接池类

public class DBConnectionPool {

static Logger logger = Logger.getLogger(DBConnectionPool.class);

private int checkedOut;
      private Vector<Connection> freeConnections = new Vector<Connection>();
      private int maxConn;
      private String password;
      p

                                                 Hibernate 支持三种继承映射策略！

1.subclass 元素映射子类:用一张表存储整个继承树的全部实例。

2.joined-subclass元素映射子类:继承树的每层实例对应一