這篇講解基于外鍵的一對(duì)一單向關(guān)聯(lián)映射

1.考察如下信息，人和身份證之間是一個(gè)一對(duì)一的關(guān)系。表的設(shè)計(jì)

注意：基于外鍵的一對(duì)一關(guān)聯(lián)的表結(jié)構(gòu)和多對(duì)一的表結(jié)構(gòu)是一致的，但是，外鍵是唯一的。

2.類的結(jié)構(gòu)

Person.java

public class Person implements Serializable{private int id;private String name;private IdCard idCard;public Person() {}public Person(String name) {super();this.name = name;}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 IdCard getIdCard() {return idCard;}public void setIdCard(IdCard idCard) {this.idCard = idCard;} }

IdCard.java

public class IdCard implements Serializable{private String id;private String address;public IdCard() {// TODO Auto-generated constructor stub }public IdCard(String id, String address) {super();this.id = id;this.address = address;}public String getId() {return id;}public void setId(String id) {this.id = id;}public String getAddress() {return address;}public void setAddress(String address) {this.address = address;}}

3.映射文件信息：

IdCard.hbm.xml

<hibernate-mapping package="cn.sxt.pojo"><class name="IdCard" table="t_idCard"><id name="id"><generator class="assigned"></generator></id><property name="address"/></class> </hibernate-mapping>

Person.hbm.xml

<hibernate-mapping package="cn.sxt.pojo"><class name="Person" table="t_person"><id name="id"><generator class="native"></generator></id><property name="name"/><!-- 基于外鍵的一對(duì)一和多對(duì)一的表結(jié)構(gòu)是一樣的，所以映射文件也一樣，要保證外鍵是唯一的 --><many-to-one name="idCard" column="idCardId" unique="true"></many-to-one></class> </hibernate-mapping>

4.測(cè)試

public class HibernateTest {/*** 生成數(shù)據(jù)庫(kù)表的工具方法* */@Testpublic void testCreateDB(){Configuration cfg = new Configuration().configure();SchemaExport se = new SchemaExport(cfg);//第一個(gè)參數(shù) 是否打印sql腳本//第二個(gè)參數(shù) 是否將腳本導(dǎo)出到數(shù)據(jù)庫(kù)中執(zhí)行se.create(true, true);}/*** 初始化表數(shù)據(jù)*/@Testpublic void testInit(){Session session = null;Transaction tx = null;try {session = HibernateUtil.getSession();tx = session.beginTransaction();IdCard card1 = new IdCard("110086", "湖北武當(dāng)");IdCard card2 = new IdCard("110087", "光明頂");Person p1 = new Person("張三瘋");p1.setIdCard(card1);Person p2 = new Person("殷素素");p2.setIdCard(card2);session.save(card1);session.save(card2);session.save(p1);session.save(p2);tx.commit();} catch (Exception e) {if(tx!=null)tx.rollback();}finally {HibernateUtil.close();}}/***/@Testpublic void testGetData(){Session session = HibernateUtil.getSession();Person p1 = (Person)session.get(Person.class, 1);System.out.println(p1.getName()+"----"+p1.getIdCard().getId()+"----"+p1.getIdCard().getAddress());HibernateUtil.close();} }

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轉(zhuǎn)載于:https://www.cnblogs.com/Vincent-yuan/p/11203267.html

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