hibernate--ID生成策略--XML

 

xml生成id, 

 

a) generator

 

b) 常用4个: native, uuid, identity, sequence

 

 

1. 新建java项目,  引入hibernate, junit(user library)和sql包

2. 新建包 com.bjsxt.hibernate, class: Student.java:

package com.bjsxt.hibernate;

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;
	}

}

3. 新建Student.hbm.xml:  使用generator class  , 换成uuid的话, 需要把 Student.java里的id改成String类型

<?xml version="1.0"?>
<!DOCTYPE hibernate-mapping PUBLIC
        "-//Hibernate/Hibernate Mapping DTD 3.0//EN"
        "http://hibernate.sourceforge.net/hibernate-mapping-3.0.dtd">
<hibernate-mapping package="com.bjsxt.hibernate">
    <class name="Student" table="_student">
        <id name="id">
        	<generator class="native"></generator>
        </id>
        <property name="name"/>
        <property name="age"/>
    </class>
</hibernate-mapping>

4. 配置hibernate.cfg.xml放在src下.    update重要, 否则不用新生成id

5. 创建log4j.properties在src下:

6. 项目右键新建source folder---"test"

7. 项目下新建package  com.bjsxt.hibernate, 和上面同名;

8. junit test文件里加入Studnet的测试代码

package com.bjsxt.hibernate;


import org.hibernate.HibernateException;
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;

public class HibernateIDTest {
	private static SessionFactory sf=null;
	@BeforeClass
	public static void beforeClass(){
		try {
			sf=new AnnotationConfiguration().configure().buildSessionFactory();
		} catch (HibernateException e) {
			// TODO Auto-generated catch block
			e.printStackTrace();
		}
	}
	@AfterClass
	public static void afterClass(){
		sf.close();
	}
	
	@Test
	public void testStudentSave() {
		Student s =new Student();
		s.setName("wddddf");
		s.setAge(23);
		
		Session session =  sf.openSession();
		session.beginTransaction();
		session.save(s);
		session.getTransaction().commit();
		session.close();	
	}
	
	@Test
	public void testTeacherSave() {
		Teacher t =new Teacher();
		t.setName("wdf");
		t.setTitle("higfdfsdfsadh");
		
		
		Session session =  sf.openSession();
		session.beginTransaction();
		session.save(t);
		session.getTransaction().commit();
		session.close();	
	}
	
	
}

9. run as->junit test, 就会自动递增id, 生成新纪录