Hinbernate继承映射为4张表注解版【不太理解】（二十一）

1

package com.bjsxt.hibernate;

import javax.persistence.Entity;
import javax.persistence.GeneratedValue;
import javax.persistence.GenerationType;
import javax.persistence.Id;
import javax.persistence.Inheritance;
import javax.persistence.InheritanceType;
import javax.persistence.TableGenerator;

@Entity
@Inheritance(strategy=InheritanceType.TABLE_PER_CLASS)
@TableGenerator(
name="t_gen",
table="t_gen_table",
pkColumnName="t_pk",
valueColumnName="t_value",
pkColumnValue="person_pk",
initialValue=1,
allocationSize=1
)
public class Person {
private int id;
private String name;

@Id
@GeneratedValue(generator="t_gen", strategy=GenerationType.TABLE)
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;
}

}



2
package com.bjsxt.hibernate;

import javax.persistence.Entity;

@Entity
public class Student extends Person {

private int score;

public int getScore() {
return score;
}

public void setScore(int score) {
this.score = score;
}

}


3
package com.bjsxt.hibernate;

import javax.persistence.Entity;

@Entity
public class Teacher extends Person {
private String title;

public String getTitle() {
return title;
}

public void setTitle(String title) {
this.title = title;
}

}


4
package com.bjsxt.hibernate;

import org.hibernate.Session;
import org.hibernate.SessionFactory;
import org.hibernate.cfg.AnnotationConfiguration;
import org.hibernate.tool.hbm2ddl.SchemaExport;
import org.junit.AfterClass;
import org.junit.BeforeClass;
import org.junit.Test;

public class HibernateORMappingTest {
private static SessionFactory sessionFactory;

@BeforeClass
public static void beforeClass() {
new SchemaExport(new AnnotationConfiguration().configure()).create(false, true);
sessionFactory = new AnnotationConfiguration().configure().buildSessionFactory();
}
@AfterClass
public static void afterClass() {
sessionFactory.close();
}

@Test
public void testSave() {
Student s = new Student();
s.setName("s1");
s.setScore(80);
Teacher t = new Teacher();
t.setName("t1");
t.setTitle("中级");

Session session = sessionFactory.openSession();
session.beginTransaction();
session.save(s);
session.save(t);
session.getTransaction().commit();
session.close();
}
@Test
public void testLoad() {
testSave();
Session session = sessionFactory.openSession();
session.beginTransaction();
Student s = (Student)session.load(Student.class, 1);
System.out.println(s.getScore());
Person p = (Person)session.load(Person.class, 2);
System.out.println(p.getName());
session.getTransaction().commit();
session.close();

}

@Test
public void testSchemaExport() {
new SchemaExport(new AnnotationConfiguration().configure()).create(false, true);
}

public static void main(String[] args) {
beforeClass();
}
}