Hibernate 一对多（OneToMary）

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;