hibernate通过配置文件生成数据库信息

hibernate可以通过配置文件在数据库生成相应的数据库信息。也可以把数据库的信息生成相应的代码(实体类操作类和映射文件)

下面是通过代码默认对hibernate.cfg.xml信息在数据库生成信息。事先要建好空的数据库

 <?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="show_sql">true</property>
         <property name="hibernate.dialect">org.hibernate.dialect.MySQLDialect</property>
         <property name="hibernate.connection.driver_class">com.mysql.jdbc.Driver</property>
         <property name="hibernate.connection.url">jdbc:mysql://localhost:3306/guesswhat?useUnicode=true&amp;characterEncoding=utf8</property>
         <property name="hibernate.connection.username">root</property>
         <property name="hibernate.connection.password">1234</property>
         <mapping resource="com/us/google/domains/TUser.hbm.xml"/>
         <mapping resource="com/us/google/domains/TUrl.hbm.xml"/>
     </session-factory>
 </hibernate-configuration> 

hibernate.cfg.xml

列出一个表的单独配置信息

 <?xml version="1.0" encoding="UTF-8"?>
 <!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.us.google.domains">
     <class name="TUser" table="t_user">
         <id name="id" column="id">
             <generator class="identity"></generator>
         </id>
         <property name="username" column="username"></property>
         <property name="password" column="password"></property>
     </class>
 </hibernate-mapping> 

TUser.hbm.xml

执行操作

 package com.us.google.util;
 
 import org.hibernate.cfg.Configuration;
 import org.hibernate.tool.hbm2ddl.SchemaExport;
 
 public class GenerateSql {
 
     public static void main(String[] args) {
 
         //默认读取hibernate.cfg.xml
         Configuration cfg = new Configuration().configure();
 
         //生成并输出sql到文件(当前目录)和数据库
         SchemaExport export = new SchemaExport(cfg);
 
         //true 在控制台打印sql语句，true 导入sql语句到数据库，即可执行
         export.create(true, true);
     }
 }

GenerateSql

运行截图如下，在控制台打印出了执行的sql语句（建立表）

即在数据生成了信息。但是这样比较麻烦，等下说建好表如何生成代码

发现上面的写法过时了 现在是hibernate5 推荐下面的写法

ServiceRegistry serviceRegistry = (ServiceRegistry) new StandardServiceRegistryBuilder()
                .configure().build();
        MetadataImplementor metadataImplementor = (MetadataImplementor) new MetadataSources(
                serviceRegistry).buildMetadata();
        SchemaExport export = new SchemaExport(serviceRegistry,
                metadataImplementor);
        export.create(true, true);

Test.java