1. Hibernate通过实体类与hbm创建表

Hibernate通过实体类与hbm.xml创建表

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开始尝试了很多次，都没能成功创建表，问题在于

<property name="hibernate.dialect">org.hibernate.dialect.MySQL5Dialect</property>
or
<property name="hibernate.dialect">org.hibernate.dialect.MySQLDialect</property>

生成的语句不同(见6)

老版本的MySQL使用TYPE而不是ENGINE（例如，TYPE = MYISAM）。MySQL 5.1为向下兼容而支持这个语法，但TYPE现在被轻视，而ENGINE是首先的用法。

MySQLDialect ->“type=MyISAM”

MySQL5Dialect->“engine=MyISAM”

应该使用MySQL5Dialect

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1. 项目结构

   

2. 创建实体类

   Student.java

   public class Student implements Serializable {
       private int id;
       private String name;
       private int age;
   	...//getter setter
   }
   

3. 创建映射

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   Student.hbm.xml

   <?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>
       <class name="learn.hibernate.entity.Student" table="stu_tab" >
           <id name="id" column="stu_id">
               <generator class="native"/>
           </id>
           <property name="name" column="stu_name"/>
           <property name="age" column="stu_age"/>
       </class>
   </hibernate-mapping>
   

4. 配置

   hibernate.cfg.xml

   <hibernate-configuration>
       <session-factory>
           
           <!--配置数据库连接-->
           <property name="connection.url">jdbc:mysql://localhost:3306/test</property>
           <property name="connection.driver_class">com.mysql.cj.jdbc.Driver</property>
           <property name="hibernate.dialect">org.hibernate.dialect.MySQL5Dialect</property>
   
           <property name="connection.username">root</property>
           <property name="connection.password">123</property>
         
           <!--显示sql语句-->
           <property name="show_sql">true</property>
           <property name="format_sql">true</property>
         
           <!--设置映射-->   
           <mapping resource="learn/hibernate/entity/Student.hbm.xml"/>
           <!-- DB schema will be updated if needed -->
           <!-- <property name="hbm2ddl.auto">update</property> -->
       </session-factory>
   </hibernate-configuration>
   

5. 测试类

   StudentTest.java

   public class StudentTest {
       //测试在数据库中根据Student类以及Student.hbm.xml创建表
       @Test
       public void createTable(){
           ServiceRegistry sr = new StandardServiceRegistryBuilder().configure().build();
           Metadata md=new MetadataSources(sr).buildMetadata();
           SchemaExport se=new SchemaExport();
           se.create(EnumSet.of(TargetType.DATABASE), md);
       }
   }
   

6. 控制台输出

   • MySQL5Dialect

     <property name="hibernate.dialect">org.hibernate.dialect.MySQL5Dialect</property>
     

     可以成功创建表，语句如下

     Hibernate: 
         drop table if exists stu_tab
     
     Hibernate: 
         create table stu_tab (
            stu_id integer not null auto_increment,
             stu_name varchar(255),
             stu_age integer,
             primary key (stu_id)
         ) engine=MyISAM
     

   • MySQLDialect

     <property name="hibernate.dialect">org.hibernate.dialect.MySQLDialect</property>
     

     无法创建，语句如下

     Hibernate: 
         drop table if exists stu_tab
     
     Hibernate: 
         create table stu_tab (
            stu_id integer not null auto_increment,
             stu_name varchar(255),
             stu_age integer,
             primary key (stu_id)
         ) type=MyISAM
     

     ​

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