Hibernate 第五讲 数据库Id生成策略 （1）

hibernate.cfg.xml

<?xml version='1.0' encoding='utf-8'?><!DOCTYPE hibernate-configuration PUBLIC        "-//Hibernate/Hibernate Configuration DTD 3.0//EN"        "http://hibernate.sourceforge.net/hibernate-configuration-3.0.dtd"><hibernate-configuration>    <session-factory>        <!-- Database connection settings -->        <!--        <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">123456</property>        -->    <!-- SQL dialect -->    <!--        <property name="dialect">org.hibernate.dialect.MySQLDialect</property>    -->        <property name="connection.driver_class">oracle.jdbc.driver.OracleDriver</property>        <property name="connection.url">jdbc:oracle:thin:@localhost:1521:hibernate</property>        <property name="connection.username">scott</property>        <property name="connection.password">tiger</property>        <property name="dialect">org.hibernate.dialect.OracleDialect</property>              <!-- JDBC connection pool (use the built-in) -->        <!-- <property name="connection.pool_size">1</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.NoCacheProvider</property>        <!-- Echo all executed SQL to stdout -->        <property name="show_sql">true</property>          <property name="format_sql">true</property>        <!-- Drop and re-create the database schema on startup -->        <property name="hbm2ddl.auto">update</property>        <mapping class="com.darren.hibernate.model.Student" />        <mapping class="com.darren.hibernate.model.Teacher" />    </session-factory></hibernate-configuration>

实体类配置方式：

package com.darren.hibernate.model;import java.util.Date;import javax.persistence.Entity;import javax.persistence.GeneratedValue;import javax.persistence.Id;@Entitypublic class Teacher {    private int id;    private String name;    private String title;    private String yourWifeName;    private Date birthDate;    @Id    @GeneratedValue    // id 生成侧略，对于mysql来说，生成策略为auto_increment，对于oracle来说，生成策略为hibernate_serence    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 String getTitle() {        return title;    }    public void setTitle(String title) {        this.title = title;    }    public String getYourWifeName() {        return yourWifeName;    }    public void setYourWifeName(String yourWifeName) {        this.yourWifeName = yourWifeName;    }    public Date getBirthDate() {        return birthDate;    }    public void setBirthDate(Date birthDate) {        this.birthDate = birthDate;    }}

测试类：

package com.darren.hiobernate.model;import java.util.Date;import org.hibernate.Session;import org.hibernate.SessionFactory;import org.hibernate.cfg.AnnotationConfiguration;import org.junit.AfterClass;import org.junit.BeforeClass;import org.junit.Test;import com.darren.hibernate.model.Student;import com.darren.hibernate.model.Teacher;public class HibernateIDTest { private static SessionFactory sessionFactory;  @BeforeClass public static void beforeClass() {   sessionFactory = new AnnotationConfiguration().configure().buildSessionFactory(); } @AfterClass public static void afterClass() {  sessionFactory.close(); }  @Test public void testStudentSave() {  Student s = new Student();  s.setAge(8);    Session session = sessionFactory.getCurrentSession();  session.beginTransaction();  session.save(s);  session.getTransaction().commit(); }  @Test public void testTeacherSave() {   Teacher t = new Teacher();  t.setId(1);  t.setName("t1");  t.setTitle("middle");  t.setBirthDate(new Date());    Session session = sessionFactory.getCurrentSession();  session.beginTransaction();  session.save(t);  session.getTransaction().commit(); }  public static void main(String[] args) {  beforeClass(); }}