hibernate方便的操作数据库相当不错的 请各位下载看看啊

				//$Id: Parent.java,v 1.2 2004/12/05 21:30:17 epbernard Exp $				package org.hibernate.test.metadata.manytoone;								import javax.ejb.Entity;				import javax.ejb.AccessType;				import javax.ejb.Id;				import java.io.Serializable;								/**				 * @author Emmanuel Bernard				 */				@Entity(access = AccessType.FIELD)				public class Parent implements Serializable {					@Id					public ParentPk id;					public int age;									public int hashCode() {						//a NPE can occurs, but I don't expect hashcode to be used before pk is set						return id.hashCode();					}									public boolean equals(Object obj) {						//a NPE can occurs, but I don't expect equals to be used before pk is set						if (obj != null && obj instanceof Parent) {							return id.equals( ( (Parent) obj).id );						}						else {							return false;						}					}				}