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  • hibernate 之 关联映射的基于外键的单向一对一映射

    1. 人和身份证是一个一对一的关系,他们的表结构为:

    2. 类结构:IdCard.java :

    public class IdCard {
        private String id;
        private String address;
        public IdCard() {
        }
        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;
        }
    }

    person.java :

    public class Person {
        private int id;
        private String name;
        private int age;
        private IdCard idCard;
        public Person() {
        }
        public Person(String name, int age) {
            super();
            this.name = name;
            this.age = age;
        }
    
        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 int getAge() {
            return age;
        }
        public void setAge(int age) {
            this.age = age;
        }
        public IdCard getIdCard() {
            return idCard;
        }
        public void setIdCard(IdCard idCard) {
            this.idCard = idCard;
        }
        
    }

    3. 映射文件:IdCard.hbm.xml :

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

    Person.hbm.xml :

    <hibernate-mapping>
        <class name="cn.wh.vo.Person" table="t_person">
            <id name="id">
                <generator class="native"></generator>
            </id>
            <property name="name"/>
            <property name="age"/>
            <!-- 配置基于外键的一对一的关联映射
                和多对一映射几乎一致,需要设置unique=true
             -->
            <many-to-one name="idCard" column="idCardId" unique="true"/>
        </class>
    </hibernate-mapping>

    4. 测试:

    public class HibernateTest {
        private Session session=null;
        @Before
        public void setUp(){
            session = HibernateUtil.getSession();
        }
        @After
        public void tearDown(){
            HibernateUtil.close();
        }
        @Test
        public void testCreateDB(){
            Configuration cfg = new Configuration().configure();
            SchemaExport export = new SchemaExport(cfg);
            //第一个参数  是否打印  数据库脚本
            //第二个参数 是否将脚本导入数据库执行
            export.create(true, true);
        }
        @Test
        public void testInit(){
            Transaction tx = null;
            try {
                tx = session.beginTransaction();
                IdCard card1 = new IdCard("1101","北京昌平");
                IdCard card2 = new IdCard("1102", "北京海淀");
                Person p1 = new Person("张三",22);
                p1.setIdCard(card1);
                Person p2 = new Person("李四",23);
                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();
            }
        }
        @Test
        public void testGet(){
            Person p1 = (Person)session.get(Person.class, 1);
            System.out.println(p1.getName()+"---"+p1.getAge()+"----"+p1.getIdCard().getAddress());
        }
        
    }
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  • 原文地址:https://www.cnblogs.com/forever2h/p/6736945.html
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