Hibernate 注解案例 - 数据库编程

一、介绍

在以前弄hibernate的时候，每创建一个数据库表都要在entity下新建对应的*.hbm.xml 配置文件，当数据库表很多之后就会严重影响开发效率和维护成本，所以就有了注解，原理在于省去之前繁琐的配置文件，取代的是在实体类中加上以“@”开头的标记，命之为注解，待会一一解释其中含义：

二、准备

jar 文件：

hibernate-core-3.3.2.GA.jar

ejb3-persistence-1.0.2.GA.jar

hibernate-annotations-3.4.0.GA.jar

hibernate-commons-annotations-3.1.0.GA.jar

javassist-3.11.0.GA.jar

（缺一不可）

三、实现

package com.hibernate.entity;

import java.io.Serializable;

import javax.persistence.Column;
import javax.persistence.Entity;
import javax.persistence.FetchType;
import javax.persistence.GeneratedValue;
import javax.persistence.GenerationType;
import javax.persistence.Id;
import javax.persistence.JoinColumn;
import javax.persistence.JoinTable;
import javax.persistence.ManyToOne;
import javax.persistence.SequenceGenerator;
import javax.persistence.Table;

/**
* 电影详情类
* @author Administrator
*
*/
@Entity //标记为数据库表
@Table(name = "tb_film_info") // 指定该实体类映射的对应的数据库表名
public class FilmInfo implements Serializable{

private static final long serialVersionUID = 1L;

private Long fiId;
private String fiName;
private String fiActor;
private String fiDirector;
private Double fiTicketPrice;

private FilmType filmType;

@Id //主键id
@SequenceGenerator(name = "generator", sequenceName = "seq_film_info" ) //指定序列
@GeneratedValue(generator = "generator", strategy = GenerationType.SEQUENCE) //指定主键生成策略
@Column(name = "fi_id") //因为数据表中的结构都是以“_”分割，然后 hibernate默认识别方式没有以任何方式分割，所以每个列都要在getter()方法标记
public Long getFiId() {
return fiId;
}
public void setFiId(Long fiId) {
this.fiId = fiId;
}
@Column(name = "fi_name")
public String getFiName() {
return fiName;
}
public void setFiName(String fiName) {
this.fiName = fiName;
}
@Column(name = "fi_actor")
public String getFiActor() {
return fiActor;
}
public void setFiActor(String fiActor) {
this.fiActor = fiActor;
}
@Column(name = "fi_director")
public String getFiDirector() {
return fiDirector;
}
public void setFiDirector(String fiDirector) {
this.fiDirector = fiDirector;
}
@Column(name = "fi_ticket_price")
public Double getFiTicketPrice() {
return fiTicketPrice;
}
public void setFiTicketPrice(Double fiTicketPrice) {
this.fiTicketPrice = fiTicketPrice;
}
@ManyToOne(fetch = FetchType.LAZY) //多对一关联关系，采用@ManyToOne标记，指定下加载方式
@JoinColumn(name = "fi_film_type_id") //指定下关联的外键
public FilmType getFilmType() {
return filmType;
}
public void setFilmType(FilmType filmType) {
this.filmType = filmType;
}
}

package com.hibernate.entity;

import java.io.Serializable;
import java.util.ArrayList;
import java.util.List;

import javax.persistence.CascadeType;
import javax.persistence.Column;
import javax.persistence.Entity;
import javax.persistence.FetchType;
import javax.persistence.GeneratedValue;
import javax.persistence.GenerationType;
import javax.persistence.Id;
import javax.persistence.JoinColumn;
import javax.persistence.OneToMany;
import javax.persistence.SequenceGenerator;
import javax.persistence.Table;

/**
* 电影类型类
* @author Administrator
*
*/
@Entity//标记为数据库表
@Table(name = "tb_film_type")// 指定该实体类映射的对应的数据库表名
public class FilmType implements Serializable{

private static final long serialVersionUID = 1L;

private Long ftId;
private String ftName;

private List filmInfos = new ArrayList();

@Id
@SequenceGenerator(name = "generator

Hibernate 注解案例(一)