Hibernate入门

Hibernate入门 一、hibernate介绍

    ①、ORM框架/持久层框架    jdbc的一个框架；

     ②、object reference mapping    对象关系映射；

     ③、 通过管理对象来改变数据库中的数据 ，通过管理对象来 *** 作数据库；

优势：跨数据库的无缝移植

二、在项目中添加hibernate支持

  1 添加hibernate相关依赖

  2 在resource目录下添加hibernate.cfg.xml(核心配置文件)

   ① 添加DTD支持

   ② 添加Hibernate的配置

    （1） 数据库相关

(connection.username|connection.password|connection.url|connection.driver_class|dialect)

    （2） 调试相关(show_sql|format_sql)

  3 在开发阶段再创建实体类和实体映射文件(*.hbm.xml) 

     实体必须实现Serializable接口

小结：hibernate.cfg.xml(1) Configuration configure = new Configuration().configure("/hibernate.cfg.xml"); SessionFactory sessionFactory = configure.buildSessionFactory(); Session session = sessionFactory.openSession(); List list = session.createQuery("from User").list(); for (Object object : list) { System.out.println(object); } session.close(); } }

结果（控制台）：

Hibernate: 
    select
        user0_.id as id1_0_,
        user0_.user_name as user_nam2_0_,
        user0_.user_pwd as user_pwd3_0_,
        user0_.real_name as real_nam4_0_,
        user0_.sex as sex5_0_,
        user0_.birthday as birthday6_0_,
        user0_.create_datetime as create_d7_0_,
        user0_.remark as remark8_0_ 
    from
        t_hibernate_user user0_
User [id=1, userName=rrr, userPwd=999, realName=null, sex=null, birthday=null, createDatetime=null, remark=null]
User [id=2, userName=ls, userPwd=123, realName=李四, sex=男, birthday=2000-11-10, createDatetime=2018-09-29 17:58:13.0, remark=xyz]
User [id=3, userName=zzz2, userPwd=123, realName=null, sex=null, birthday=2018-09-29, createDatetime=2018-09-29 18:07:20.0, remark=null]
User [id=4, userName=zzz2, userPwd=123, realName=null, sex=null, birthday=2018-10-06, createDatetime=2018-10-06 15:17:54.0, remark=null]
User [id=5, userName=bbbb, userPwd=123s, realName=null, sex=null, birthday=null, createDatetime=2018-10-17 00:12:53.0, remark=null]
User [id=6, userName=ttttt, userPwd=6666, realName=null, sex=null, birthday=null, createDatetime=2018-10-17 19:46:20.0, remark=null]
User [id=7, userName=吃吃吃, userPwd=mima, realName=null, sex=null, birthday=null, createDatetime=2018-10-17 23:01:55.0, remark=null]
User [id=9, userName=吃吃吃22, userPwd=mima, realName=null, sex=null, birthday=null, createDatetime=2018-10-17 23:08:45.0, remark=null]
User [id=11, userName=xxx, userPwd=123456, realName=xxx, sex=1, birthday=null, createDatetime=2018-11-17 17:47:03.0, remark=xxx]
User [id=12, userName=xxx, userPwd=123456, realName=xxx, sex=1, birthday=null, createDatetime=2018-11-17 17:48:17.0, remark=xxx]
User [id=13, userName=xxx, userPwd=123456, realName=xxx, sex=1, birthday=2018-11-17, createDatetime=2018-11-17 17:48:48.0, remark=xxx]
User [id=14, userName=精华, userPwd=123456, realName=金燕, sex=女, birthday=null, createDatetime=2018-11-18 17:24:38.0, remark=开小差]
 

主键生成器

generator元素：表示了一个主键生成器，它用来为持久化类实例生成唯一的标识 。

 1、 程序员自己控制：assigned

  2、数据库控制: identity(标识列/自动增长) sequence

  3、 hibernate控制:increment uuid/uuid.hex

  4、 其它:native

②增加

package com.dhm.test;

import java.sql.Date;
import java.sql.Timestamp;
import java.util.List;

import org.hibernate.Session;
import org.hibernate.SessionFactory;
import org.hibernate.Transaction;
import org.hibernate.cfg.Configuration;

import com.dhm.entity.User;

public class AddDemo {
	public static void main(String[] args) {
		
        Configuration configure = new Configuration().configure("/hibernate.cfg.xml");
		SessionFactory sessionFactory = configure.buildSessionFactory();
		Session session = sessionFactory.openSession();
		Transaction transaction = session.beginTransaction();
		
		User user=new User();
		user.setBirthday(new Date(System.currentTimeMillis()));
		user.setCreateDatetime(new Timestamp(System.currentTimeMillis()));
		user.setId(55);
		user.setRealName("xxd");
		user.setRemark("武侠剧");
		user.setSex("男");
		user.setUserName("四条眉毛");
		user.setUserPwd("123456");
		session.save(user);
		
		transaction.commit();
		session.close();
		
	}
}

结果：

数据库新增一条

 ③修改

package com.dhm.test;

import java.util.List;

import org.hibernate.Session;
import org.hibernate.SessionFactory;
import org.hibernate.Transaction;
import org.hibernate.cfg.Configuration;

import com.dhm.entity.User;

public class EditDemo {
	public static void main(String[] args) {
		Configuration configure = new Configuration().configure("/hibernate.cfg.xml");
		SessionFactory sessionFactory = configure.buildSessionFactory();
		Session session = sessionFactory.openSession();
		Transaction transaction = session.beginTransaction();
		
		User user = session.get(User.class, 55);
		user.setRealName("a带");
		transaction.commit();
		session.close();
		
	
	}

}

结果：

控制台

Hibernate: 
    select
        user0_.id as id1_0_0_,
        user0_.user_name as user_nam2_0_0_,
        user0_.user_pwd as user_pwd3_0_0_,
        user0_.real_name as real_nam4_0_0_,
        user0_.sex as sex5_0_0_,
        user0_.birthday as birthday6_0_0_,
        user0_.create_datetime as create_d7_0_0_,
        user0_.remark as remark8_0_0_ 
    from
        t_hibernate_user user0_ 
    where
        user0_.id=?
Hibernate: 
    update
        t_hibernate_user 
    set
        user_name=?,
        user_pwd=?,
        real_name=?,
        sex=?,
        birthday=?,
        remark=? 
    where
        id=?

数据库

 ④、删除

package com.dhm.test;

import org.hibernate.Session;
import org.hibernate.SessionFactory;
import org.hibernate.Transaction;
import org.hibernate.cfg.Configuration;

import com.dhm.entity.User;

public class DelDemo {
	public static void main(String[] args) {
		Configuration configure = new Configuration().configure("/hibernate.cfg.xml");
		SessionFactory sessionFactory = configure.buildSessionFactory();
		Session session = sessionFactory.openSession();
		Transaction transaction = session.beginTransaction();
		
		User user = session.get(User.class, 55);
		session.delete(user);
		transaction.commit();
		session.close();
		
	}

}

控制台

Hibernate: 
    select
        user0_.id as id1_0_0_,
        user0_.user_name as user_nam2_0_0_,
        user0_.user_pwd as user_pwd3_0_0_,
        user0_.real_name as real_nam4_0_0_,
        user0_.sex as sex5_0_0_,
        user0_.birthday as birthday6_0_0_,
        user0_.create_datetime as create_d7_0_0_,
        user0_.remark as remark8_0_0_ 
    from
        t_hibernate_user user0_ 
    where
        user0_.id=?
Hibernate: 
    delete 
    from
        t_hibernate_user 
    where
        id=?