hibernate------初识

1.创建db_hibernate数据库，在创建的数据库中创建一个students表

2.创建一个Java项目（项目中添加hibernate所需类库）

3.项目中添加hibernate.cfg.xml配置文件，完善配置信息

 1 <?xml version="1.0" encoding="UTF-8"?>
 2 <!DOCTYPE hibernate-configuration PUBLIC
 3     "-//Hibernate/Hibernate Configuration DTD 3.0//EN"
 4     "http://www.hibernate.org/dtd/hibernate-configuration-3.0.dtd">
 5 <hibernate-configuration>
 6 <session-factory>
 7 <!-- 数据库连接文件 -->
 8 <property name="connection.driver_class">com.mysql.jdbc.Driver</property>
 9 <property name="connection.url">jdbc:mysql://localhost:3306/db_hibernate</property>
10 <property name="connection.username">root</property>
11 <property name="connection.password">775297</property>
12 <!-- 数据库连接池 -->
13 <property name="connection.pool_size">1</property>
14 <!-- sql方言 -->
15 <property name="dialect">org.hibernate.dialect.MySQL5Dialect</property>
16 <!-- session环境 -->
17 <property name="current_session_context_class">thread</property>
18 <!-- 打印sql语句 -->
19 <property name="show_sql">true</property>
20 <!-- 格式化SQL语句 -->
21 <property name="format_sql">true</property>
22 <!-- 加载配置文件 -->
23 <mapping resource="com/zdsofe/hibernate/Student.hbm.xml"/>
24 </session-factory>
25 </hibernate-configuration>    
26

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4.创建Student实体类，为该类提供私有属性和get/set方法

 1 package com.zdsofe.hibernate;
 2 
 3 import java.util.Date;
 4 
 5 public class Student {
 6  
 7     private int id;
 8     private String name;
 9     private String sex;
10     private Date birthday;
11 
12     public int getId() {
13         return id;
14     }
15     public void setId(int id) {
16         this.id = id;
17     }
18     public String getName() {
19         return name;
20     }
21     public void setName(String name) {
22         this.name = name;
23     }
24     public String getSex() {
25         return sex;
26     }
27     public void setSex(String sex) {
28         this.sex = sex;
29     }
30     public Date getBirthday() {
31         return birthday;
32     }
33     public void setBirthday(Date birthday) {
34         this.birthday = birthday;
35     }
36     
37     
38 }

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5.在Student类的包下添加一个映射文件Student.hbm.xml

 1 <?xml version="1.0" encoding="UTF-8"?>
 2 <!DOCTYPE hibernate-mapping PUBLIC 
 3     "-//Hibernate/Hibernate Mapping DTD 3.0//EN"
 4     "http://www.hibernate.org/dtd/hibernate-mapping-3.0.dtd">
 5   
 6 <hibernate-mapping package="com.zdsofe.hibernate">
 7   <!-- 定义实体类与数据库之间的映射 -->
 8   <class name="Student" table="students">
 9       <!--定义表主键与属性之间的映射关系 -->
10       <id name="id" column="id">
11           <!-- 指定主键的生产方式 -->
12           <generator class="native"></generator>
13       </id>
14       <!-- 普通属性与表的映射关系,名字相同可以写一个 -->
15       <property name="name" column="name"></property>
16       <property name="sex"></property>
17       <property name="birthday" type="date"></property>
18   </class>
19   
20 </hibernate-mapping>

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6.创建SessionFactory对象，获取Session对象通过Session对象以面向对象形式操作关系型数据库

 1 package com.zdsofe.hibernate;
 2 
 3 import java.util.Date;
 4 
 5 import org.hibernate.Session;
 6 import org.hibernate.SessionFactory;
 7 import org.hibernate.boot.registry.StandardServiceRegistryBuilder;
 8 import org.hibernate.cfg.Configuration;
 9 import org.hibernate.service.ServiceRegistry;
10 
11 public class Test {
12 
13     public static void main(String[] args) {
14       //通过配置文件对象获得配置文件
15       Configuration cfg = new Configuration().configure();
16       //获取服务注册器对象
17       StandardServiceRegistryBuilder ssrb = new StandardServiceRegistryBuilder();
18       //获得注册器对象
19       ServiceRegistry serviceRegistry = ssrb.applySettings(cfg.getProperties()).build();
20       //创建SessionFactory
21       SessionFactory sessionFactory = cfg.buildSessionFactory(serviceRegistry);
22       //通过session工厂创建session
23       Session session = sessionFactory.getCurrentSession();
24       //开启事务
25       session.beginTransaction();
26       //进行数据库操作      
27       Student stu = new Student(); //(瞬时状态,随时可能被销毁，被垃圾回收器回收)
28       stu.setName("饶鹏");
29       stu.setSex("女");
30       stu.setBirthday(new Date());
31      
32       //保存数据
33       Integer i = (Integer)session.save(stu);//当stu对象和session关联，并且有个唯一的标识(主键)，那么此时的状态称为持久化
34       System.out.println(i);
35       stu.setSex("男");//处于持久化状态时会直接修改，不用调用save、update等
36       //查询
37       /*  Student stu2 = (Student) session.get(Student.class, 4);*/
38       //删除
39       /* session.delete(stu2);*/   //此时stu属于删除态，不建议使用
40       //提交事务
41       session.getTransaction().commit();//此时的状态称为脱管状态(此时的session已经销毁)
42       
43       //重新获取session
44       session=sessionFactory.getCurrentSession();
45       //开启事务
46       session.beginTransaction();
47       session.update(stu);//在此与session关联，那么此时的状态称为持久化
48       //提交事务
49       session.getTransaction().commit();
50      
51          
52     }
53 
54 }

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以编程的方式获得配置文件

 1 package com.zdsofe.hibernate;
 2 
 3 import org.hibernate.Session;
 4 import org.hibernate.SessionFactory;
 5 import org.hibernate.boot.registry.StandardServiceRegistryBuilder;
 6 import org.hibernate.cfg.Configuration;
 7 import org.hibernate.service.ServiceRegistry;
 8 
 9 public class Test1 {
10 
11     public static void main(String[] args) {
12         //以编程的方式获得配置文件
13         Configuration cfg=new Configuration();
14         cfg.setProperty("hibernate.connection.driver_class","com.mysql.jdbc.Driver" );
15         cfg.setProperty("hibernate.connection.url", "jdbc:mysql://localhost:3306/db_hibernate");
16         cfg.setProperty("hibernate.connection.username", "root");
17         cfg.setProperty("hibernate.connection.password", "775297");
18         cfg.setProperty("hibernate.dialect", "org.hibernate.dialect.MySQL5Dialect");
19         cfg.setProperty("hibernate.current_session_context_class", "thread");
20         cfg.addResource("com/zdsofe/hibernate/Student.hbm.xml");
21         //获得注册器对象
22         ServiceRegistry  serviceRegistry=new StandardServiceRegistryBuilder().applySettings(cfg.getProperties()).build();
23         //创建session工厂
24         SessionFactory  sessionFactory=cfg.buildSessionFactory(serviceRegistry);
25         //创建session
26         Session session=sessionFactory.getCurrentSession();
27         //开启事务
28         session.beginTransaction();
29         //提交事务
30         session.getTransaction().commit();
31         
32         
33         
34     }
35 }

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