例子:老师与学生的一对多
老师实体类
package entity;
import java.util.HashSet;
import java.util.Set;
/**
* Teacher 实体类
* */
public class Teacher2 {
private int id;//编号
private String name;//姓名
private Set<Student2> student2=new HashSet<Student2>();
/*
* 构造方法
* */
public Teacher2() {
}
public Teacher2(String name) {
this.name = name;
}
/*
* 封装方法
* */
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 Set<Student2> getStudent2() {
return student2;
}
public void setStudent2(Set<Student2> student2) {
this.student2 = student2;
}
}
老师实体类的XML配置
<?xml version="1.0" encoding="utf-8"?>
<!DOCTYPE hibernate-mapping PUBLIC "-//Hibernate/Hibernate Mapping DTD 3.0//EN"
"http://hibernate.sourceforge.net/hibernate-mapping-3.0.dtd">
<hibernate-mapping>
<class name="entity.Teacher2">
<id name="id">
<generator class="sequence">
<param name="sequence">seq_teacher2</param>
</generator>
</id>
<property name="name"></property>
<set name="student2">
<key column="teacher2id"></key>
<one-to-many class="entity.Student2" />
</set>
</class>
</hibernate-mapping>
学生实体类
package entity;
/**
* Student 实体类
* */
public class Student2 {
private int id;//编号
private String name;//姓名
/*
* 构造方法
* */
public Student2() {
}
public Student2(String name) {
this.name = name;
}
/*
* 封装方法
* */
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;
}
}
学生实体类的XML配置
<?xml version="1.0" encoding="utf-8"?>
<!DOCTYPE hibernate-mapping PUBLIC "-//Hibernate/Hibernate Mapping DTD 3.0//EN"
"http://hibernate.sourceforge.net/hibernate-mapping-3.0.dtd">
<hibernate-mapping>
<class name="entity.Student2">
<id name="id">
<generator class="sequence">
<param name="sequence">seq_student2</param>
</generator>
</id>
<property name="name"></property>
</class>
</hibernate-mapping>
使用hibernate.cfg.xml映射其的XML路径
<!DOCTYPE hibernate-configuration PUBLIC
"-//Hibernate/Hibernate Configuration DTD 3.0//EN"
"http://hibernate.sourceforge.net/hibernate-configuration-3.0.dtd">
<hibernate-configuration>
<session-factory>
<!-- 数据库URL -->
<property name="connection.url">
jdbc:oracle:thin:@localhost:1521:oracle11
</property>
<!-- 数据库用户 -->
<property name="connection.username">A_hr</property>
<!-- 数据库用户密码 -->
<property name="connection.password">123456</property>
<!-- 数据库 JDBC 驱动 -->
<property name="connection.driver_class">
oracle.jdbc.driver.OracleDriver
</property>
<!-- 是否将运行期生成的 SQL 输出到日志以供调试 -->
<property name="show_sql">true</property>
<!-- 每个数据库都有其对应的 Dialect 以匹配其平台特征 -->
<property name="dialect">
org.hibernate.dialect.Oracle10gDialect
</property>
<property name="hbm2ddl.auto">create</property>
<mapping resource="entity/Student2.hbm.xml" />
<mapping resource="entity/Teacher2.hbm.xml" />
</session-factory>
</hibernate-configuration>
进行数据的操作
package test;
import org.hibernate.HibernateException;
import org.hibernate.Session;
import org.hibernate.Transaction;
import entity.Student2;
import entity.Teacher2;
import util.HibernateSessionFactory;
public class OneToMaryTest {
public static void main(String[] args) {
oneToMary();
}
private static void oneToMary() {
Session session = HibernateSessionFactory.getSession();
Transaction tx = null;
Teacher2 teacher = new Teacher2("李炎恢");
Student2 student1 = new Student2("吴者然");
Student2 student2 = new Student2("何开");
try {
teacher.getStudent2().add(student1);
teacher.getStudent2().add(student2);
tx = session.beginTransaction();
session.save(teacher);
session.save(student1);
session.save(student2);
tx.commit();
System.out.println("保存成功!!!");
} catch (HibernateException e) {
e.printStackTrace();
tx.rollback();
}finally{
HibernateSessionFactory.closeSession();
}
}
}
效果图:
在数据库查询这两条语句
select id, name from teacher2;
select id, name, teacher2id from student2;