Hibrenate入门实例

1.创建数据库
新建数据库

create database test;

新建表：
主键id(自增长)
字符串格式的name
浮点数格式的price

use test;CREATE TABLE prodyct_ (  id int(11) NOT NULL AUTO_INCREMENT,  name varchar(30) ,  price float ,  PRIMARY KEY (id)) DEFAULT CHARSET=UTF8;

2.创建java项目，导入项目所需的包
3.创建与表对应的实体类product

package com.ljx;public class product {    int id;    String name;    float price;    public int getId() {        return id;    }    public void setId(int id) {        this.id = id;    }    public String getName() {        return name;    }    public void setName(String name) {        this.name = name;    }    public float getPrice() {        return price;    }    public void setPrice(float price) {        this.price = price;    }}

4.配置 Product.hbm.xml（连接数据库的一系列配置）

<?xml version="1.0"?><!DOCTYPE hibernate-mapping PUBLIC        "-//Hibernate/Hibernate Mapping DTD 3.0//EN"        "http://www.hibernate.org/dtd/hibernate-mapping-3.0.dtd"><hibernate-mapping package="com.ljx">    <class name="product" table="prodyct_">        <id name="id" column="id">            <generator class="native"></generator>        </id>        <property name="name"/>        <property name="price"/>    </class></hibernate-mapping>

 <id name="id" column="id">          <generator class="native"></generator> </id>

表示属性id,映射表里的字段id

 <generator class="native">意味着id的自增长方式采用数据库的本地方式

<property name="name"/>

只写了属性name,没有通过column=”name” 显式的指定字段，那么对应表里的字段的名字也是name.

5.配置 hibernate.cfg.xml（有关hibernate的一系列配置）

<?xml version='1.0' encoding='utf-8'?><!DOCTYPE hibernate-configuration PUBLIC        "-//Hibernate/Hibernate Configuration DTD 3.0//EN"        "http://www.hibernate.org/dtd/hibernate-configuration-3.0.dtd"><hibernate-configuration>    <session-factory>        <!-- Database connection settings -->        <property name="connection.driver_class">com.mysql.jdbc.Driver</property>        <property name="connection.url">jdbc:mysql://localhost:3306/test2?characterEncoding=UTF-8</property>        <property name="connection.username">root</property>        <property name="connection.password"></property>        <!-- SQL dialect -->        <property name="dialect">org.hibernate.dialect.MySQLDialect</property>        <property name="current_session_context_class">thread</property>        <property name="show_sql">true</property>        <property name="hbm2ddl.auto">update</property>        <mapping resource="com/ljx/product.hbm.xml"/>    </session-factory></hibernate-configuration>

1.配置访问数据库要用到的驱动，url，账号密码
2.<property name="dialect">org.hibernate.dialect.MySQLDialect</property>表示告诉Hibernate底层使用的数据库是mysql
3.<property name="current_session_context_class">thread</property>是Hibernate事务管理方式，即一个线程对应一个事务
4.<property name="show_sql">true</property>表示是否在控制台显示执行的mysql语句
5.<property name="hbm2ddl.auto">update</property>表示是否自动更新数据库的表结构
6.<mapping resource="com/ljx/product.hbm.xml"/>表示Hibernate会去识别Product这个实体类

6.测试类TestHibernate

package com.ljx;import org.hibernate.Session;import org.hibernate.SessionFactory;import org.hibernate.cfg.Configuration;public class testHibernate {    public static void main(String[] args){        Configuration configuration = new Configuration();        configuration.configure("com/ljx/hibernate.cfg.xml");        SessionFactory sf = configuration.buildSessionFactory();        Session s = sf.openSession();        s.beginTransaction();        product p = new product();        p.setName("xiaoa");        p.setPrice(1000);        s.save(p);        s.getTransaction().commit();        s.close();        sf.close();    }}

创建一个Product对象，并通过hibernate把这个对象，插入到数据库中
hibernate的基本步骤是：
1.获取hibernate配置文件
2.获取SessionFactory
3.通过SessionFactory获取Session
4.在Session上开启事务
5.通过调用Session的save方法把对象保存到数据库
6.提交事务
7.关闭Session
8. 关闭SessionFactory

7.hibernate实现增删改查

package com.ljx;import org.hibernate.Session;import org.hibernate.SessionFactory;import org.hibernate.Transaction;import org.hibernate.cfg.Configuration;public class testHibernate2 {    Configuration configuration;    SessionFactory sf;    Session s;    Transaction t;    public testHibernate2(){        configuration = new Configuration();        configuration.configure("com/ljx/hibernate.cfg.xml");        sf= configuration.buildSessionFactory();    }    public void add(product product){        s = sf.openSession();        t = s.beginTransaction();        s.save(product);        t.commit();        s.close();    }    public void delete(int id){        s = sf.openSession();        t = s.beginTransaction();        s.delete(s.get(product.class,id));       // product p = (product)s.get(product.class,new Integer(2));        t.commit();        s.close();    }    public void update(product product){        s = sf.openSession();        t = s.beginTransaction();        s.update(product);        t.commit();        s.close();    }    public product getById(int id){        s = sf.openSession();        t = s.beginTransaction();        product p = (product)s.get(product.class,id);        t.commit();        s.close();        return p;    }    public static void main(String[] args){        testHibernate2 th = new testHibernate2();        //增加        product p_1 = new product();        p_1.setName("add");        p_1.setPrice(10);        th.add(p_1);        //删除        int id_2 = 3;        th.delete(id_2);        //修改        product p_3 = new product();        p_3.setId(1);        p_3.setName("update");        p_3.setPrice(20);        th.update(p_3);        //查找        int id_4 = 1;        product p_4 = th.getById(id_4);        System.out.println(p_4.getId());        System.out.println(p_4.getName());        System.out.println(p_4.getPrice());    }}

运行前：

运行后：

控制台输出：