Java EE入门教程系列第六章Hibernate框架（三）——第一个Hibernate项目

超、凢脫俗 2022-04-12 08:39 289阅读 0赞

6.3 创建一个Hibernate项目

6.3.1 Hibernate项目开发的一般步骤

1）新建Java工程

2）导入MySQL数据库的JDBC驱动

3）导入Hibernate库

4）新建POJO文件

5）创建POJO文件对应的数据库及表

6）新建Hibernate配置文件hibernate.cfg.xml

7）新建Hibernate映射向导（就是选择数据库和数据表）文件hibernate.hbm.xml

8）编写main（）函数，通过Hibernate配置文件和映射文件对POJO类进行持久化处理，将对该类的操作永久地保存到MySQL数据库中

6.3.2 项目实例（注意：根据数据库版本和hibernate版本的不同，配置、java语句也有所不同，最好根据自己的版本去找资料）

首先介绍一下如何在eclipse配置hibernate环境：

打开eclipse，点击help-->eclipse marketplace,如图输入:Hibernate 搜索，找到JBoss Tools

![watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L3FxXzQwOTk2MDQx_size_16_color_FFFFFF_t_70][]

点击install安装

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选择Hibernate Tools，点击Confrm安装。安装完成后重启eclipse，项目右键->new->other，如果有Hibernate Configuration File则说明配置成功。

![watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L3FxXzQwOTk2MDQx_size_16_color_FFFFFF_t_70 2][]

接着先去官网下载需要的jar包：[http://hibernate.org/orm/][http_hibernate.org_orm]

![watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L3FxXzQwOTk2MDQx_size_16_color_FFFFFF_t_70 3][]

点击releases-overview，选择右上角latest版本，选择需要的版本，点击download等待几秒后就开始下载了

![watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L3FxXzQwOTk2MDQx_size_16_color_FFFFFF_t_70 4][]

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下面按照之前说的步骤进行：

1）新建一个Java应用程序项目，命名H1。file-new-project-java-java project

![watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L3FxXzQwOTk2MDQx_size_16_color_FFFFFF_t_70 6][]

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2）添加mysql驱动程序。右击项目-build path-configure build path-add external jars找到你自己电脑里的数据库jar包加入

3）添加hibernate库。右键项目-build path-add libraries-user libraries-new-随便填写一个名字（我填的是hibernate）-add external jars将解压完的各个文件夹jar包都加入进来

![watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L3FxXzQwOTk2MDQx_size_16_color_FFFFFF_t_70 8][]

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导入后结构为：

![watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L3FxXzQwOTk2MDQx_size_16_color_FFFFFF_t_70 10][]

4）创建实体类User1。在项目H1中新建java类文件，命名为User1.java。

import java.util.Date;
    public class User1 {
    	private int id;
    	private String username;
    	private String password;
    	private Date createTime;
    	private Date expireTime;
    	public int getId() {
    		return id;
    	}
    	public void setId(int id) {
    		this.id = id;
    	}
    	public String getUsername() {
    		return username;
    	}
    	public void setUsername(String username) {
    		this.username = username;
    	}
    	public String getPassword() {
    		return password;
    	}
    	public void setPassword(String password) {
    		this.password = password;
    	}
    	public Date getCreateTime() {
    		return createTime;
    	}
    	public void setCreateTime(Date createTime) {
    		this.createTime = createTime;
    	}
    	public Date getExpireTime() {
    		return expireTime;
    	}
    	public void setExpireTime(Date expireTime) {
    		this.expireTime = expireTime;
    	}
    }

5）创建数据库及表。首先创建数据库studb，接着在此数据库中创建表user1，表结构中的每个字段应与User1类中定义的成员变量一一对应，数据类型也应该是对应的，如下图（数据库的下载、建表不再介绍）：

![20181203074557387.png][]

6）新建hibernate配置文件。先新建包h1（下图是没有新建包的情况，后面觉得还是放在包里比较好），然后项目src右键-new-other-找到下图

![watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L3FxXzQwOTk2MDQx_size_16_color_FFFFFF_t_70 11][]

![watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L3FxXzQwOTk2MDQx_size_16_color_FFFFFF_t_70 12][]

注意：这一步版本不能选择最新的，否则点击finish会出现没有响应无法创建的情况！！！

![watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L3FxXzQwOTk2MDQx_size_16_color_FFFFFF_t_70 13][]

<?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>
      <property name="hibernate.connection.driver_class">com.mysql.jdbc.Driver</property>
      <property name="hibernate.connection.password">java</property>
      <property name="hibernate.connection.url">jdbc:mysql://localhost:3306/studb</property>
      <property name="hibernate.connection.username">root</property>
      <property name="hibernate.dialect">org.hibernate.dialect.MySQLDialect</property>
      <mapping resource="User1.hbm.xml"/>
     </session-factory>
    </hibernate-configuration>

7）新建hibernate映射向导（就是选择数据库和数据表）

![watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L3FxXzQwOTk2MDQx_size_16_color_FFFFFF_t_70 14][]

![watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L3FxXzQwOTk2MDQx_size_16_color_FFFFFF_t_70 15][]

可以找到项目工作空间，找到该xml文件，用记事本打开查看或者修改，由此文件可以看出类和表的映射关系

<?xml version="1.0" encoding="UTF-8"?>
    <!DOCTYPE hibernate-mapping PUBLIC "-//Hibernate/Hibernate Mapping DTD 3.0//EN"
    "http://hibernate.sourceforge.net/hibernate-mapping-3.0.dtd">
    
    <hibernate-mapping>
        <class name="h1.User1" table="user1">
            <id name="id" type="int">
                <column name="id" />
                <generator class="increment" />
            </id>
            <property name="username" type="java.lang.String">
                <column name="username" />
            </property>
            <property name="password" type="java.lang.String">
                <column name="password" />
            </property>
            <property name="createTime" type="java.util.Date">
                <column name="createTime" />
            </property>
            <property name="expireTime" type="java.util.Date">
                <column name="expireTime" />
            </property>
        </class>
    </hibernate-mapping>

8）编写main（）函数H1.java

import java.util.Date;
    
    import org.hibernate.HibernateException;
    import org.hibernate.Session;
    import org.hibernate.SessionFactory;
    import org.hibernate.Transaction;
    import org.hibernate.cfg.Configuration;
    
    public class H1 {
    
    	public static void main(String[] args) {
    		// TODO Auto-generated method stub
     try {
    	 SessionFactory sf=new Configuration().configure().buildSessionFactory();
    	 Session session=sf.openSession();
    	 Transaction tx=session.beginTransaction();
    	 for(int i=0;i<5;i++) {
    		 User1 u1=new User1();
    		 u1.setUsername("user"+i);
    		 u1.setPassword("java");
    		 u1.setCreateTime(new Date());
    		 u1.setExpireTime(new Date());
    		 session.save(u1);//将User1对象逐个保存到session中
    		 
    	 }
    	 tx.commit();//提交事务，将User1对象永久化保存到数据库中
    	 session.close();
     }catch(HibernateException e) {
    	 e.printStackTrace();
     }
    	}
    
    }

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[http_hibernate.org_orm]: http://hibernate.org/orm/
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[20181203074557387.png]: /images/20220412/5fa2ea6c13444ce6bee2283f67ef3bd1.png
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