hibernate（一）第一个例子

一、创建一个java project名为HibernateDemo1

然后导入hibernate包,eclipse中具体操作：

点击菜单栏windows->preferences->java->bulid path->User Libraries

然后new->输入hibernate（不勾选下边的选择框）->add external jars这时候就要选择包了，将下载的hibernate4.3.11目录lib下required中的jar文件全部加载。然后在项目上右键选择bulid path->add libraries->user libraries 然后选择刚才创建的hibernate。这时hibernate就加载进来了

然后再加载mysql驱动，项目上右键bulid path->add external archives 选择下载的mysql JDBC驱动包

二、在mysql数据库中创建测试表student

create database hibernate;

use hibernate;

create table student(
id int auto_increment primary key,
name varchar(20),
age int
);

三、写代码

创建包cn.orlion.hibernate.model,然后创建一个Student类：

package cn.orlion.hibernate.model;

public class Student {
    
    private int id;
    
    private String name;
    
    private int age;

    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 int getAge() {
        return age;
    }

    public void setAge(int age) {
        this.age = age;
    }
}

然后创建hibernate配置文件hibernate.cfg.xml,在src目录下创建这个文件，然后将参考文档中的配置copy进去（如下：）修改mysql配置，注释掉暂时用不到的项

<?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>

        <!-- 数据库连接配置 -->
        <property name="connection.driver_class">com.mysql.jdbc.Driver</property>
        <property name="connection.url">jdbc:mysql://localhost/hibernate</property>
        <property name="connection.username">root</property>
        <property name="connection.password"></property>

        <!-- hibernate自带JDBC 连接池，暂时不用注释掉 -->
        <!-- <property name="connection.pool_size">1</property> -->

        <!-- 改成MySqlDialect(mysql的sql语句) -->
        <property name="dialect">org.hibernate.dialect.MySQLDialect</property>

        <!-- Enable Hibernate's automatic session context management -->
        <!-- <property name="current_session_context_class">thread</property> -->

        <!-- Disable the second-level cache  -->
        <property name="cache.provider_class">org.hibernate.cache.internal.NoCacheProvider</property>

        <!-- 打印出所有的sql -->
        <property name="show_sql">true</property>

        <!-- Drop and re-create the database schema on startup -->
        <!-- <property name="hbm2ddl.auto">update</property> -->

        <mapping resource="cn/orlion/hibernate/model/Student.hbm.xml"/>

    </session-factory>

</hibernate-configuration>

然后在cn.orlion.hibernate.model（跟实体类放一起）下创建文件Student.hbn.xml,从参考文档中copy修改

<?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="cn.orlion.hibernate.model">
    <class name="Student" table="student"><!-- 如果表名与类名相同可以不用写table属性 -->
        <!-- 用id映射主键 -->
        <id name="id" column="id"> <!-- 列名相同可以不指定column属性 -->
        </id>
        
        <property name="name" column="name"></property>
        <property name="age"></property>
    </class>
</hibernate-mapping>

然后创建一个包cn.orlion.test创建类StudentTest

package cn.orlion.test;

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

import cn.orlion.hibernate.model.Student;

public class StudentTest {
    
    public static void main(String[] args){
        
        Student s = new Student();
        s.setId(1);
        s.setName("test1");
        s.setAge(1);
        
        Configuration cfg = new Configuration();
        
        SessionFactory sf = cfg.configure().buildSessionFactory();// 这里会提示deprecated,但是按着参考文档会报错
        
        Session session = sf.openSession();
        
        session.beginTransaction();
        session.save(s);
        session.getTransaction().commit();
        
        session.close();
        
        sf.close();
    }
}

右键然后运行就可以看到数据库中存入了一条数据：