Hibernate Annotation 基于外键的单向多对一关联

其实一对多和多对一是一样的，只是看问题的角度不同。

需要的注解标签请参考前面的文章，那些标签是我从前面项目总结下来的

SQL脚本：

-- MySQL dump 10.13  Distrib 5.1.55, for Win32 (ia32)
--
-- Host: localhost    Database: hibernate_demo
-- ------------------------------------------------------
-- Server version	5.1.55-community

/*!40101 SET @OLD_CHARACTER_SET_CLIENT=@@CHARACTER_SET_CLIENT */;
/*!40101 SET @OLD_CHARACTER_SET_RESULTS=@@CHARACTER_SET_RESULTS */;
/*!40101 SET @OLD_COLLATION_CONNECTION=@@COLLATION_CONNECTION */;
/*!40101 SET NAMES utf8 */;
/*!40103 SET @OLD_TIME_ZONE=@@TIME_ZONE */;
/*!40103 SET TIME_ZONE='+00:00' */;
/*!40014 SET @OLD_UNIQUE_CHECKS=@@UNIQUE_CHECKS, UNIQUE_CHECKS=0 */;
/*!40014 SET @OLD_FOREIGN_KEY_CHECKS=@@FOREIGN_KEY_CHECKS, FOREIGN_KEY_CHECKS=0 */;
/*!40101 SET @OLD_SQL_MODE=@@SQL_MODE, SQL_MODE='NO_AUTO_VALUE_ON_ZERO' */;
/*!40111 SET @OLD_SQL_NOTES=@@SQL_NOTES, SQL_NOTES=0 */;

--
-- Table structure for table `category`
--

DROP TABLE IF EXISTS `category`;
/*!40101 SET @saved_cs_client     = @@character_set_client */;
/*!40101 SET character_set_client = utf8 */;
CREATE TABLE `category` (
  `id` int(11) NOT NULL AUTO_INCREMENT,
  `name` varchar(30) NOT NULL,
  `description` varchar(30) NOT NULL,
  PRIMARY KEY (`id`)
) ENGINE=MyISAM AUTO_INCREMENT=2 DEFAULT CHARSET=utf-8;
/*!40101 SET character_set_client = @saved_cs_client */;

--
-- Dumping data for table `category`
--

LOCK TABLES `category` WRITE;
/*!40000 ALTER TABLE `category` DISABLE KEYS */;
INSERT INTO `category` VALUES (1,'fruit','fruit category');
/*!40000 ALTER TABLE `category` ENABLE KEYS */;
UNLOCK TABLES;

--
-- Table structure for table `product`
--

DROP TABLE IF EXISTS `product`;
/*!40101 SET @saved_cs_client     = @@character_set_client */;
/*!40101 SET character_set_client = utf8 */;
CREATE TABLE `product` (
  `id` int(11) NOT NULL,
  `name` varchar(30) NOT NULL,
  `price` int(11) NOT NULL,
  `description` varchar(30) NOT NULL,
  `category_id` int(11) NOT NULL,
  PRIMARY KEY (`id`),
  KEY `product_fk` (`category_id`)
) ENGINE=MyISAM DEFAULT CHARSET=latin1;
/*!40101 SET character_set_client = @saved_cs_client */;

--
-- Dumping data for table `product`
--

LOCK TABLES `product` WRITE;
/*!40000 ALTER TABLE `product` DISABLE KEYS */;
INSERT INTO `product` VALUES (1,'apple',10,'apple',1);
/*!40000 ALTER TABLE `product` ENABLE KEYS */;
UNLOCK TABLES;
/*!40103 SET TIME_ZONE=@OLD_TIME_ZONE */;

/*!40101 SET SQL_MODE=@OLD_SQL_MODE */;
/*!40014 SET FOREIGN_KEY_CHECKS=@OLD_FOREIGN_KEY_CHECKS */;
/*!40014 SET UNIQUE_CHECKS=@OLD_UNIQUE_CHECKS */;
/*!40101 SET CHARACTER_SET_CLIENT=@OLD_CHARACTER_SET_CLIENT */;
/*!40101 SET CHARACTER_SET_RESULTS=@OLD_CHARACTER_SET_RESULTS */;
/*!40101 SET COLLATION_CONNECTION=@OLD_COLLATION_CONNECTION */;
/*!40111 SET SQL_NOTES=@OLD_SQL_NOTES */;

-- Dump completed on 2012-08-08 22:34:53

 

//Category.java

package com.zyp.examples;

import javax.persistence.Column;
import javax.persistence.Entity;
import javax.persistence.GeneratedValue;
import javax.persistence.GenerationType;
import javax.persistence.Id;
import javax.persistence.Table;

import org.hibernate.annotations.GenericGenerator;

/**
 * Category entity. @author MyEclipse Persistence Tools
 */

@Entity
@Table(name="category")
public class Category implements java.io.Serializable {

	// Fields
	private static final long serialVersionUID = 3763960444574701564L;

	@Id
	@GenericGenerator(name="incrementGenerator", strategy="increment")
	@GeneratedValue(generator="incrementGenerator", strategy=GenerationType.IDENTITY)
	@Column(name="id")
	private Integer id;
	
	@Column(name="name",nullable=false, insertable=true)
	private String name;
	
	@Column(name="description", nullable=false, insertable=true)
	private String description;

	// Constructors

	/** default constructor */
	public Category() {
	}

	/** full constructor */
	public Category(String name, String description) {
		this.name = name;
		this.description = description;
	}

	// Property accessors

	public Integer getId() {
		return this.id;
	}

	public void setId(Integer id) {
		this.id = id;
	}

	public String getName() {
		return this.name;
	}

	public void setName(String name) {
		this.name = name;
	}

	public String getDescription() {
		return this.description;
	}

	public void setDescription(String description) {
		this.description = description;
	}

}

 

//Product.java

package com.zyp.examples;

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.ManyToOne;
import javax.persistence.Table;

import org.hibernate.annotations.GenericGenerator;

/**
 * Product entity. @author MyEclipse Persistence Tools
 */

@Entity
@Table(name="product")
public class Product implements java.io.Serializable {

	// Fields

	private static final long serialVersionUID = -485648626582047874L;

	@Id
	@GenericGenerator(name="incrementGenerator", strategy="increment")
	@GeneratedValue(generator="incrementGenerator", strategy=GenerationType.IDENTITY)
	@Column(name="id")
	private Integer id;
	
	@Column(name="name")
	private String name;
	
	@Column(name="price")
	private Integer price;
	
	@Column(name="description")
	private String description;
	
	@ManyToOne(targetEntity=Category.class, fetch=FetchType.LAZY, cascade={CascadeType.ALL})
	@JoinColumn(name="category_id")
	private Category category;

	// Constructors

	/** default constructor */
	public Product() {
	}

	// Property accessors

	public Integer getId() {
		return this.id;
	}

	public void setId(Integer id) {
		this.id = id;
	}

	public String getName() {
		return this.name;
	}

	public void setName(String name) {
		this.name = name;
	}

	public Integer getPrice() {
		return this.price;
	}

	public void setPrice(Integer price) {
		this.price = price;
	}

	public String getDescription() {
		return this.description;
	}

	public void setDescription(String description) {
		this.description = description;
	}

	public Category getCategory() {
		return category;
	}

	public void setCategory(Category category) {
		this.category = category;
	}
	
	

}

 

//HibernateUti.java

package com.zyp.examples;

import org.hibernate.SessionFactory;
import org.hibernate.cfg.AnnotationConfiguration;
import org.hibernate.cfg.Configuration;

public class HibernateUtil {
	private static SessionFactory sessionFactory;
	static {
		try {
			sessionFactory = new AnnotationConfiguration().configure()
					.buildSessionFactory();
		} catch (Throwable ex) {
			throw new ExceptionInInitializerError(ex);
		}
	}

	public static SessionFactory getSessionFactory() {
		return sessionFactory;
	}

	public static void shutdown() {
		getSessionFactory().close();
	}
}

 

//Hibernate.cfg.xml

<?xml version='1.0' encoding='UTF-8'?>
<!DOCTYPE hibernate-configuration PUBLIC
          "-//Hibernate/Hibernate Configuration DTD 3.0//EN"
          "http://hibernate.sourceforge.net/hibernate-configuration-3.0.dtd">

<!-- Generated by MyEclipse Hibernate Tools.                   -->
<hibernate-configuration>

<session-factory>
	<property name="dialect">
		org.hibernate.dialect.MySQLDialect
	</property>
	<property name="connection.url">
		jdbc:mysql://localhost:3306/hibernate_demo
	</property>
	<property name="connection.username">root</property>
	<property name="connection.password">123</property>
	<property name="connection.driver_class">
		com.mysql.jdbc.Driver
	</property>
	<property name="myeclipse.connection.profile">mysql</property>
	<property name="show_sql">true</property>
	<property name="format_sql">true</property>
	
	<mapping class="com.zyp.examples.Category" />
	<mapping class="com.zyp.examples.Product" />

</session-factory>

</hibernate-configuration>

 

经过这个例子，我也发现主键生成方式参数的设定了，呵呵。。

	@Id
	@GenericGenerator(name="incrementGenerator(可以随便取一个名字)", strategy="increment(主键生成策略)")
	@GeneratedValue(generator="incrementGenerator(和上面的保持一致)", strategy=GenerationType.IDENTITY(根据需要从注解中选一个值))
	@Column(name="id")
	private Integer id;