（1）、编写配置文件
Hibernate通过读写默认的XML配置文件hibernate.cfg.xml加载数据库配置信息、代码如下：
<hibernate-configuration>
<session-factory>
<!-- 数据库驱动 -->
<property name="connection.driver_class">com.mysql.jdbc.Driver</property>
<!-- 数据库连接的URL -->
<property name="connection.url">jdbc:mysql://localhost:3306/db_database14</property>
<!-- 数据库连接用户名 -->
<property name="connection.username">root</property>
<!-- 数据库连接密码 -->
<property name="connection.password"></property>
<!-- Hibernate方言 -->
<property name="dialect">org.hibernate.dialect.MySQLDialect</property>
<!-- 打印SQL语句 -->
<property name="show_sql">true</property>
<!-- 映射文件 -->
<mapping resource="com/wgh/model/Book.hbm.xml" />
<mapping resource="com/wgh/model/Category.hbm.xml" />
</session-factory>
</hibernate-configuration>
（2）、编写持久化类
持久化类是Hibernate操作的对象、它与数据库中的数据表相对应
（双向）
/**
* 图书类别持久化类
*/
public class Category {
private Integer id; //ID
private String name; //类别名称
private Set<Book> books; //Set集合（类别中的所有图书）
public Integer getId() {
return id;
}
public void setId(Integer id) {
this.id = id;
}
public String getName() {
return name;
}
public void setName(String name) {
this.name = name;
}
public Set<Book> getBooks() {
return books;
}
public void setBooks(Set<Book> books) {
this.books = books;
}
}
（单向）
/**
* 图书类别持久化类
*/
public class Category {
private Integer id; //ID
private String name; //类别名称
public Integer getId() {
return id;
}
public void setId(Integer id) {
this.id = id;
}
public String getName() {
return name;
}
public void setName(String name) {
this.name = name;
}
}
/**
* 图书持久类
*/
public class Book {
private Integer id; //ID
private String name; //图书名称
private String author;
private Category category; //所属类别
public Integer getId() {
return id;
}
public void setId(Integer id) {
this.id = id;
}
public String getName() {
return name;
}
public void setName(String name) {
this.name = name;
}
public String getAuthor() {
return author;
}
public void setAuthor(String author) {
this.author = author;
}
public Category getCategory() {
return category;
}
public void setCategory(Category category) {
this.category = category;
}
}
（3）、编写映射文件
(双向)
<hibernate-mapping package="com.wgh.model">
<class name="Category" table="tb_Category_manytoone3">
<id name="id">
<generator class="native"/>
</id>
<property name="name" not-null="true" length="200" />
<!-- 一对多映射 -->
<set name="books">
<key column="categoryId"/>
<one-to-many class="Book"/>
</set> </class>
</hibernate-mapping>
（单向）
<hibernate-mapping package="com.wgh.model">
<class name="Category" table="tb_Category_manytoone0">
<id name="id">
<generator class="native"/>
</id>
<property name="name" not-null="true" length="200" />
</class>
</hibernate-mapping>
<hibernate-mapping package="com.wgh.model">
<class name="Book" table="tb_book_manytoone0">
<!-- 主键 -->
<id name="id">
<generator class="native"/>
</id>
<!-- 图书名称 -->
<property name="name" not-null="true" length="200" />
<!-- 作者 -->
<property name="author" not-null="true" length="50"/>
<!-- 多对一关联映射 -->
<many-to-one name="category" class="Category">
<!-- 映射的字段 -->
<column name="categoryId"/>
</many-to-one>
</class>
</hibernate-mapping>
（4）、编写Hibernate的工具类
package com.wgh.hibernate; import org.hibernate.HibernateException;
import org.hibernate.Session;
import org.hibernate.SessionFactory;
import org.hibernate.cfg.Configuration;
import org.hibernate.service.ServiceRegistryBuilder; public class HibernateUtil {
private static final ThreadLocal<Session> threadLocal = new ThreadLocal<Session>();
private static SessionFactory sessionFactory = null; // SessionFactory对象
// 静态块
static {
try {
Configuration cfg = new Configuration().configure(); // 加载Hibernate配置文件
sessionFactory = cfg
.buildSessionFactory(new ServiceRegistryBuilder().applySettings(cfg.getProperties())
.buildServiceRegistry());
} catch (Exception e) {
System.err.println("创建会话工厂失败");
e.printStackTrace();
}
} /**
* 获取Session
*
* @return Session
* @throws HibernateException
*/
public static Session getSession() throws HibernateException {
Session session = (Session) threadLocal.get();
if (session == null || !session.isOpen()) {
if (sessionFactory == null) {
rebuildSessionFactory();
}
session = (sessionFactory != null) ? sessionFactory.openSession()
: null;
threadLocal.set(session);
}
return session;
} /**
* 重建会话工厂
*/
public static void rebuildSessionFactory() {
try {
Configuration cfg = new Configuration().configure(); // 加载Hibernate配置文件
sessionFactory = cfg
.buildSessionFactory(new ServiceRegistryBuilder().applySettings(cfg.getProperties())
.buildServiceRegistry());
} catch (Exception e) {
System.err.println("创建会话工厂失败");
e.printStackTrace();
}
} /**
* 获取SessionFactory对象
*
* @return SessionFactory对象
*/
public static SessionFactory getSessionFactory() {
return sessionFactory;
} /**
* 关闭Session
*
* @throws HibernateException
*/
public static void closeSession() throws HibernateException {
Session session = (Session) threadLocal.get();
threadLocal.set(null);
if (session != null) {
session.close(); // 关闭Session
}
}
}