说明文档：
英文：http://docs.jboss.org/hibernate/annotations/3.5/reference/en/html_single/
中文：http://docs.jboss.org/hibernate/annotations/3.4/reference/zh_cn/html_single/
下载：hibernate annotation 3.4.0 GA
得到：hibernate-annotations.jar
hibernate-commons-annotation.jar
ejb3-persistence.jar
数据库：mysql
category表：id，name，description <Pk>id
product表：id,name ,price, description ,category_id <pk>id <fk>category_id
新建java project项目：
Add Hibernate Capabilities
hibernate.cfg.xml
代码；
<?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:3307/users
</property>
<property name="connection.username">root</property>
<property name="connection.password">root</property>
<property name="connection.driver_class">
com.mysql.jdbc.Driver
</property>
<property name="myeclipse.connection.profile">
mysqlusers
</property>
<property name="format_sql">true</property>
<property name="show_sql">true</property>
<property name="current_session_context_class">thread</property>
<mapping class="com.b510.examples.Product" />
<mapping class="com.b510.examples.Category" />
</session-factory>
</hibernate-configuration>
利用Hibernate的逆向工程生成：
Category.java and Product.java
Category.java
package com.b510.examples;
import java.util.HashSet;
import java.util.Set;
// 标准注解
import javax.persistence.CascadeType;
import javax.persistence.Column;
import javax.persistence.Entity;
import javax.persistence.FetchType;
import javax.persistence.GeneratedValue;
import javax.persistence.Id;
import javax.persistence.OneToMany;
import javax.persistence.Table;
//增加的注解
import org.hibernate.annotations.GenericGenerator;
//当前的类是一个持久化类，是Category这个类。他映射了一个表category。所对应的 数据库是users
//这句：@Table(name = "category", catalog = "users") 可以省略
@Entity
@Table(name = "category", catalog = "users")
public class Category implements java.io.Serializable {
private static final long serialVersionUID = 3240281547213597385L;
private Integer id;
private String name;
private String description;
private Set<Product> products = new HashSet<Product>(0);
public Category() {
}
public Category(String name, String description, Set<Product> products) {
this.name = name;
this.description = description;
this.products = products;
}
// 主键 ：@Id 主键生成方式：strategy = "increment"
//映射表中id这个字段，不能为空，并且是唯一的
@GenericGenerator(name = "generator", strategy = "increment")
@Id
@GeneratedValue(generator = "generator")
@Column(name = "id", unique = true, nullable = false)
public Integer getId() {
return this.id;
}
public void setId(Integer id) {
this.id = id;
}
//映射表中name这个字段 ，长度是500
@Column(name = "name", length = 500)
public String getName() {
return this.name;
}
public void setName(String name) {
this.name = name;
}
//映射表中description这个字段 ，长度是500
@Column(name = "description", length = 500)
public String getDescription() {
return this.description;
}
public void setDescription(String description) {
this.description = description;
}
//级联操作：cascade = CascadeType.ALL
//延迟加载：fetch = FetchType.LAZY
//映射：mappedBy = "category"
//一对多方式
@OneToMany(cascade = CascadeType.ALL, fetch = FetchType.LAZY, mappedBy = "category")
public Set<Product> getProducts() {
return this.products;
}
public void setProducts(Set<Product> products) {
this.products = products;
}
}
Product.java
代码：
package com.b510.examples;
import javax.persistence.Column;
import javax.persistence.Entity;
import javax.persistence.FetchType;
import javax.persistence.GeneratedValue;
import javax.persistence.Id;
import javax.persistence.JoinColumn;
import javax.persistence.ManyToOne;
import javax.persistence.Table;
import org.hibernate.annotations.GenericGenerator;
@Entity
@Table(name = "product", catalog = "users")
public class Product implements java.io.Serializable {
private static final long serialVersionUID = -1546206493725028472L;
private Integer id;
private Category category;
private String name;
private String price;
private String descripton;
public Product() {
}
public Product(Category category, String name, String price,
String descripton) {
this.category = category;
this.name = name;
this.price = price;
this.descripton = descripton;
}
@GenericGenerator(name = "generator", strategy = "increment")
@Id
@GeneratedValue(generator = "generator")
@Column(name = "id", unique = true, nullable = false)
public Integer getId() {
return this.id;
}
public void setId(Integer id) {
this.id = id;
}
//延迟加载：多对一方式
//关联信息：外键name = "category_id"
@ManyToOne(fetch = FetchType.LAZY)
@JoinColumn(name = "category_id")
public Category getCategory() {
return this.category;
}
public void setCategory(Category category) {
this.category = category;
}
@Column(name = "name", length = 500)
public String getName() {
return this.name;
}
public void setName(String name) {
this.name = name;
}
@Column(name = "price", length = 10)
public String getPrice() {
return this.price;
}
public void setPrice(String price) {
this.price = price;
}
@Column(name = "descripton", length = 500)
public String getDescripton() {
return this.descripton;
}
public void setDescripton(String descripton) {
this.descripton = descripton;
}
}
测试代码：
HibernateTest.java
代码：
/**
*
*/
package com.b510.examples;
import java.util.Set;
import org.hibernate.Session;
import org.hibernate.SessionFactory;
import org.hibernate.cfg.AnnotationConfiguration;
import org.hibernate.cfg.Configuration;
/**
*
* @author XHW
*
* @date 2011-7-20
*
*/
public class HibernateTest {
public static void main(String[] args) {
HibernateTest test=new HibernateTest();
test.add();
test.find();
}
public void add(){
Configuration config=new AnnotationConfiguration();
config.configure();
SessionFactory sessionFactory=config.buildSessionFactory();
Session session=sessionFactory.getCurrentSession();
session.beginTransaction();
Category c=(Category)session.get(Category.class, 5);
Product p=new Product();
p.setName("计算机科学与技术");
p.setPrice("123");
p.setDescripton("计算机科学与技术,好啊，真是红啊");
p.setCategory(c);
c.getProducts().add(p);
session.save(p);
session.getTransaction().commit();
}
public void find(){
Configuration config=new AnnotationConfiguration();
config.configure();
SessionFactory sessionFactory=config.buildSessionFactory();
Session session=sessionFactory.getCurrentSession();
session.beginTransaction();
Category c=(Category)session.get(Category.class, 5);
System.out.println("id: "+c.getId()+" name:"+c.getName());
Set<Product> p=c.getProducts();
for(Product product:p){
System.out.println("id:"+product.getId()+" name:"+product.getName()+" description:"+product.getDescripton());
}
session.getTransaction().commit();
}
}
运行效果：
log4j:WARN No appenders could be found for logger (org.hibernate.cfg.annotations.Version).
log4j:WARN Please initialize the log4j system properly.
Hibernate:
select
category0_.id as id1_0_,
category0_.description as descript2_1_0_,
category0_.name as name1_0_
from
users.category category0_
where
category0_.id=?
Hibernate:
select
products0_.category_id as category5_1_,
products0_.id as id1_,
products0_.id as id0_0_,
products0_.category_id as category5_0_0_,
products0_.descripton as descripton0_0_,
products0_.name as name0_0_,
products0_.price as price0_0_
from
users.product products0_
where
products0_.category_id=?
Hibernate:
select
max(id)
from
product
Hibernate:
insert
into
users.product
(category_id, descripton, name, price, id)
values
(?, ?, ?, ?, ?)
Hibernate:
select
category0_.id as id5_0_,
category0_.description as descript2_5_0_,
category0_.name as name5_0_
from
users.category category0_
where
category0_.id=?
id: 5 name:xml33
Hibernate:
select
products0_.category_id as category5_1_,
products0_.id as id1_,
products0_.id as id4_0_,
products0_.category_id as category5_4_0_,
products0_.descripton as descripton4_0_,
products0_.name as name4_0_,
products0_.price as price4_0_
from
users.product products0_
where
products0_.category_id=?
id:9 name:计算机科学与技术 description:计算机科学与技术,好啊，真是红啊