hibernate set 集合映射

最新推荐文章于 2021-02-18 18:14:53 发布

最新推荐文章于 2021-02-18 18:14:53 发布 · 100 阅读

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#Hibernate #Java #MySQL #XML #SQL

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本文介绍了一个使用Java Hibernate框架实现的集合映射案例，通过一个Person类关联多个学校名称，展示了如何在Java类中定义集合属性、Hibernate配置文件及XML映射，并在MySQL数据库中创建相应的表结构。

Person.java


package com.aabnn.vo;

import java.util.HashSet;
import java.util.Set;

public class Person {
	private int id;
	private String name;
	private Set<String> schools = new HashSet<String>();
	public Person(){

	}
	public int getId() {
		return id;
	}
	@SuppressWarnings(value="unused")
	private void setId(int id) {
		this.id = id;
	}
	public String getName() {
		return name;
	}
	public void setName(String name) {
		this.name = name;
	}
	public Set<String> getSchools() {
		return schools;
	}
	public void setSchools(Set<String> schools) {
		this.schools = schools;
	}

}

Person.hbm.xml


<?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.aabnn.vo">
  <class name="Person" table="person">
  	<id name="id" column="id" type="integer">
  		<generator class="identity" />
  	</id>
  	<property name="name" column="name" type="string" />
  	<set name="schools" table="schools" cascade="all">
  		<key column="schoolid" not-null="true" />
  		<element type="string" column="name" not-null="true" />
  	</set>
  </class>
</hibernate-mapping>

Test.java


package com.aabnn.test;

import java.util.HashSet;
import java.util.Set;

import org.hibernate.SessionFactory;
import org.hibernate.Transaction;
import org.hibernate.cfg.Configuration;
import org.hibernate.classic.Session;

import com.aabnn.vo.Person;

public class Test {

	/**
	 * @param args
	 */
	public static void main(String[] args) {
		// TODO Auto-generated method stub
		SessionFactory sf=new Configuration().configure().buildSessionFactory();
		Session sess=sf.openSession();
		Transaction tx=sess.beginTransaction();
		Set<String> schools=new HashSet<String>();
		schools.add("快乐小学");
		schools.add("轻松中学");
		schools.add("时髦大学");
		Person p=new Person();
		p.setName("小毛");
		p.setSchools(schools);
		try{
		    sess.save(p);
		}catch(Exception e){
			tx.rollback();
		}finally{
			sess.close();
		}
	}

mysql 数据库




-- Create schema collectionmapping
--

CREATE DATABASE IF NOT EXISTS collectionmapping;
USE collectionmapping;

--
-- Definition of table `person`
--

DROP TABLE IF EXISTS `person`;
CREATE TABLE `person` (
  `id` int(10) unsigned NOT NULL auto_increment,
  `name` varchar(45) NOT NULL,
  PRIMARY KEY  (`id`)
) ENGINE=InnoDB AUTO_INCREMENT=3 DEFAULT CHARSET=utf8;

--
-- Dumping data for table `person`
--

/*!40000 ALTER TABLE `person` DISABLE KEYS */;
INSERT INTO `person` (`id`,`name`) VALUES 
 (1,'小毛'),
 (2,'小毛');
/*!40000 ALTER TABLE `person` ENABLE KEYS */;


--
-- Definition of table `schools`
--

DROP TABLE IF EXISTS `schools`;
CREATE TABLE `schools` (
  `schoolid` int(10) unsigned NOT NULL,
  `name` varchar(45) NOT NULL default '',
  PRIMARY KEY  (`schoolid`,`name`),
  CONSTRAINT `fk_schools_person` FOREIGN KEY (`schoolid`) REFERENCES `person` (`id`)
) ENGINE=InnoDB DEFAULT CHARSET=utf8;

--
-- Dumping data for table `schools`
--

/*!40000 ALTER TABLE `schools` DISABLE KEYS */;
INSERT INTO `schools` (`schoolid`,`name`) VALUES 
 (1,'快乐小学'),
 (1,'时髦大学'),
 (1,'轻松中学'),
 (2,'快乐小学'),
 (2,'时髦大学'),
 (2,'轻松中学');
/*!40000 ALTER TABLE `schools` ENABLE KEYS */;