hibernate一对一双向外键关联

一对一双向外键关联：双方都持有对方的外键关联关系。

　　主控方和一对一单向外键关联的情况是一样的，主要的差异表现为，被空方需要添加：

　　@OneToOne(mappedBy="card") //被控方

　　主控方必须交给其中的一方去控制，因为不可以双方都同时拥有控制对方的权利，假如是这样的话是没有办法保存成功的。这就是为什么需要指定mappenBy="card"的原因。

　　1、IdCard.java实体类:

package oto_bfk;

import javax.persistence.Column;
import javax.persistence.Entity;
import javax.persistence.GeneratedValue;
import javax.persistence.Id;
import javax.persistence.OneToOne;

import org.hibernate.annotations.GenericGenerator;

/*身份证类*/
@Entity
public class IdCard {

    private String pid;//身份证号
    private String sname;//学生姓名
    private Students stu;//持有主控方外键属性的引用

    @OneToOne(mappedBy="card")
    public Students getStu() {
        return stu;
    }

    public void setStu(Students stu) {
        this.stu = stu;
    }

    //无参数的构造器
    public IdCard()
    {

    }

    //带参数的构造器
    public IdCard(String pid, String sname) {
        super();
        this.pid = pid;
        this.sname = sname;
    }

    @Id//指定主键
    @Column(length=18)//指定身份证的长度
    //主键生成策略
    @GenericGenerator(name="pid",strategy="assigned")
    @GeneratedValue(generator="pid")
    public String getPid() {
        return pid;
    }

    public void setPid(String pid) {
        this.pid = pid;
    }

    public String getSname() {
        return sname;
    }

    public void setSname(String sname) {
        this.sname = sname;
    }
}

2、Students.java实体类:

package oto_bfk;

import java.io.Serializable;
import java.util.Date;

import javax.persistence.CascadeType;
import javax.persistence.Column;
import javax.persistence.Embedded;
import javax.persistence.EmbeddedId;
import javax.persistence.Entity; /*JPA注解*/
import javax.persistence.GeneratedValue;
import javax.persistence.GenerationType;
import javax.persistence.Id;
import javax.persistence.JoinColumn;
import javax.persistence.OneToOne;
import javax.persistence.Table;
import javax.persistence.Transient;

/**
 * 学生实体类
 * @author Administrator
 *
 */
//@Entity(name="t_students")
@Entity//表示这是一个实体类
//schema:表示数据库的名称
//name:表示数据库的表名
//Embedddable注解表示一个非Entity类，但是可以嵌入到另外一个实体类中作为属性而存在
public class Students implements Serializable{

    private IdCard card;
    private int sid;  //将学号改成字符串类型
    private String gender; //性别
    private Date birthday;//出生日期
    private String major;//专业

    public Students(IdCard card, String gender, Date birthday,
            String major) {
        super();
        this.card = card;
        this.sid = sid;
        this.gender = gender;
        this.birthday = birthday;
        this.major = major;
    }

    @OneToOne(cascade=CascadeType.ALL)//表示全 级联关系
    @JoinColumn(name="pid", unique=true)
    public IdCard getCard() {
        return card;
    }

    public void setCard(IdCard card) {
        this.card = card;
    }

    @Id
    @GeneratedValue//主键自增
    public int getSid() {
        return sid;
    }

    public void setSid(int sid) {
        this.sid = sid;
    }

    public String getGender() {
        return gender;
    }

    public void setGender(String gender) {
        this.gender = gender;
    }

    public Date getBirthday() {
        return birthday;
    }

    public void setBirthday(Date birthday) {
        this.birthday = birthday;
    }

    public String getMajor() {
        return major;
    }

    public void setMajor(String major) {
        this.major = major;
    }

    public Students()
    {

    }

}

3、hibernate.cfg.xml配置文件:

<?xml version="1.0" encoding="UTF-8"?>
<!DOCTYPE hibernate-configuration PUBLIC
        "-//Hibernate/Hibernate Configuration DTD 3.0//EN"
        "http://www.hibernate.org/dtd/hibernate-configuration-3.0.dtd">

<!-- old: http://hibernate.sourceforge.net/hibernate-configuration-3.6.dtd -->
<!-- new: http://hibernate.sourceforge.net/hibernate-configuration-3.0.dtd -->
<!--    : http://www.hibernate.org/dtd/hibernate-configuration-3.0.dtd -->
<hibernate-configuration>
<session-factory>
    <!-- 显示sql语句 -->
    <property name="show_sql">true</property>
    <property name="myeclipse.connection.profile">bookshop</property>
    <!-- <property name="connection.url">
        jdbc:mysql://localhost:3306/bookshop
        jdbc:mysql://localhost:3306/database?useUnicode=true&amp;characterEncoding=UTF-8
    </property> -->

    <property name="connection.url">jdbc:mysql://localhost:3306/hibernate?useUnicode=true&amp;characterEncoding=UTF-8</property>
    <property name="connection.username">root</property>
    <property name="connection.password">woaiwojia..123</property>
    <property name="connection.driver_class">com.mysql.jdbc.Driver</property>
    <property name="dialect">org.hibernate.dialect.MySQLDialect</property>
    <property name="format_sql">true</property>
    <property name="hbm2ddl.auto">update</property>
    <property name="hibernate.current_session_context_class">thread</property>

    <!-- 将实体类映射到数据库 -->
    <!--
    <mapping class="oto_fk.Students"/>
    <mapping class="oto_fk.IdCard"/>
     -->
    <mapping class="oto_bfk.Students"/>
    <mapping class="oto_bfk.IdCard"/>

</session-factory>
</hibernate-configuration>

4、生成数据库表结构:

@Test
    public void testShemaExport(){
        //创建Hibernate配置对象
        Configuration configuration = new Configuration().configure();

        //创建服务注册对象
        ServiceRegistry serviceRegistry =
                new ServiceRegistryBuilder()
        .applySettings(configuration.getProperties())
        .buildServiceRegistry();

        //创建sessionFactory
        SessionFactory sessionFactory = configuration.buildSessionFactory(serviceRegistry);

        //生成SchemaExport对象
        SchemaExport export = new SchemaExport(configuration);
        //调用schemaExport的create生成数据库表结构
        export.create(true, true);
    }

5、Log显示：

2016-4-17 20:42:47 org.hibernate.annotations.common.Version <clinit>
INFO: HCANN000001: Hibernate Commons Annotations {4.0.2.Final}
2016-4-17 20:42:47 org.hibernate.Version logVersion
INFO: HHH000412: Hibernate Core {4.2.21.Final}
2016-4-17 20:42:47 org.hibernate.cfg.Environment <clinit>
INFO: HHH000206: hibernate.properties not found
2016-4-17 20:42:47 org.hibernate.cfg.Environment buildBytecodeProvider
INFO: HHH000021: Bytecode provider name : javassist
2016-4-17 20:42:47 org.hibernate.cfg.Configuration configure
INFO: HHH000043: Configuring from resource: /hibernate.cfg.xml
2016-4-17 20:42:47 org.hibernate.cfg.Configuration getConfigurationInputStream
INFO: HHH000040: Configuration resource: /hibernate.cfg.xml
2016-4-17 20:42:47 org.hibernate.cfg.Configuration doConfigure
INFO: HHH000041: Configured SessionFactory: null
2016-4-17 20:42:47 org.hibernate.service.jdbc.connections.internal.DriverManagerConnectionProviderImpl configure
WARN: HHH000402: Using Hibernate built-in connection pool (not for production use!)
2016-4-17 20:42:47 org.hibernate.service.jdbc.connections.internal.DriverManagerConnectionProviderImpl configure
INFO: HHH000115: Hibernate connection pool size: 20
2016-4-17 20:42:47 org.hibernate.service.jdbc.connections.internal.DriverManagerConnectionProviderImpl configure
INFO: HHH000006: Autocommit mode: false
2016-4-17 20:42:47 org.hibernate.service.jdbc.connections.internal.DriverManagerConnectionProviderImpl configure
INFO: HHH000401: using driver [com.mysql.jdbc.Driver] at URL [jdbc:mysql://localhost:3306/hibernate?useUnicode=true&characterEncoding=UTF-8]
2016-4-17 20:42:47 org.hibernate.service.jdbc.connections.internal.DriverManagerConnectionProviderImpl configure
INFO: HHH000046: Connection properties: {user=root, password=****}
2016-4-17 20:42:48 org.hibernate.dialect.Dialect <init>
INFO: HHH000400: Using dialect: org.hibernate.dialect.MySQLDialect
2016-4-17 20:42:48 org.hibernate.engine.jdbc.internal.LobCreatorBuilder useContextualLobCreation
INFO: HHH000423: Disabling contextual LOB creation as JDBC driver reported JDBC version [3] less than 4
2016-4-17 20:42:48 org.hibernate.engine.transaction.internal.TransactionFactoryInitiator initiateService
INFO: HHH000399: Using default transaction strategy (direct JDBC transactions)
2016-4-17 20:42:48 org.hibernate.hql.internal.ast.ASTQueryTranslatorFactory <init>
INFO: HHH000397: Using ASTQueryTranslatorFactory
2016-4-17 20:42:49 org.hibernate.tool.hbm2ddl.SchemaUpdate execute
INFO: HHH000228: Running hbm2ddl schema update
2016-4-17 20:42:49 org.hibernate.tool.hbm2ddl.SchemaUpdate execute
INFO: HHH000102: Fetching database metadata
2016-4-17 20:42:49 org.hibernate.tool.hbm2ddl.SchemaUpdate execute
INFO: HHH000396: Updating schema
2016-4-17 20:42:49 org.hibernate.tool.hbm2ddl.DatabaseMetadata getTableMetadata
INFO: HHH000262: Table not found: IdCard
2016-4-17 20:42:49 org.hibernate.tool.hbm2ddl.DatabaseMetadata getTableMetadata
INFO: HHH000262: Table not found: Students
2016-4-17 20:42:49 org.hibernate.tool.hbm2ddl.DatabaseMetadata getTableMetadata
INFO: HHH000262: Table not found: IdCard
2016-4-17 20:42:49 org.hibernate.tool.hbm2ddl.DatabaseMetadata getTableMetadata
INFO: HHH000262: Table not found: Students
2016-4-17 20:42:49 org.hibernate.tool.hbm2ddl.DatabaseMetadata getTableMetadata
INFO: HHH000262: Table not found: IdCard
2016-4-17 20:42:49 org.hibernate.tool.hbm2ddl.DatabaseMetadata getTableMetadata
INFO: HHH000262: Table not found: Students
2016-4-17 20:42:49 org.hibernate.tool.hbm2ddl.SchemaUpdate execute
INFO: HHH000232: Schema update complete
2016-4-17 20:42:49 org.hibernate.dialect.Dialect <init>
INFO: HHH000400: Using dialect: org.hibernate.dialect.MySQLDialect
2016-4-17 20:42:49 org.hibernate.tool.hbm2ddl.SchemaExport execute
INFO: HHH000227: Running hbm2ddl schema export
2016-4-17 20:42:49 org.hibernate.service.jdbc.connections.internal.DriverManagerConnectionProviderImpl configure
WARN: HHH000402: Using Hibernate built-in connection pool (not for production use!)
2016-4-17 20:42:49 org.hibernate.service.jdbc.connections.internal.DriverManagerConnectionProviderImpl configure
INFO: HHH000115: Hibernate connection pool size: 20
2016-4-17 20:42:49 org.hibernate.service.jdbc.connections.internal.DriverManagerConnectionProviderImpl configure
INFO: HHH000006: Autocommit mode: false
2016-4-17 20:42:49 org.hibernate.service.jdbc.connections.internal.DriverManagerConnectionProviderImpl configure
INFO: HHH000401: using driver [com.mysql.jdbc.Driver] at URL [jdbc:mysql://localhost:3306/hibernate?useUnicode=true&characterEncoding=UTF-8]
2016-4-17 20:42:49 org.hibernate.service.jdbc.connections.internal.DriverManagerConnectionProviderImpl configure
INFO: HHH000046: Connection properties: {user=root, password=****}

    alter table Students
        drop
        foreign key FK_mryi31xkbwbosevquurf60ivb

    drop table if exists IdCard

    drop table if exists Students

    create table IdCard (
        pid varchar(18) not null,
        sname varchar(255),
        primary key (pid)
    )

    create table Students (
        sid integer not null auto_increment,
        birthday datetime,
        gender varchar(255),
        major varchar(255),
        pid varchar(18),
        primary key (sid)
    )

    alter table Students
        add constraint UK_mryi31xkbwbosevquurf60ivb unique (pid)

    alter table Students
        add index FK_mryi31xkbwbosevquurf60ivb (pid),
        add constraint FK_mryi31xkbwbosevquurf60ivb
        foreign key (pid)
        references IdCard (pid)
2016-4-17 20:42:49 org.hibernate.service.jdbc.connections.internal.DriverManagerConnectionProviderImpl stop
INFO: HHH000030: Cleaning up connection pool [jdbc:mysql://localhost:3306/hibernate?useUnicode=true&characterEncoding=UTF-8]
2016-4-17 20:42:49 org.hibernate.tool.hbm2ddl.SchemaExport execute
INFO: HHH000230: Schema export complete

6、添加学生记录测试：

@Test
    public void addStudents()
    {
        //创建Hibernate配置对象
        Configuration configuration = new Configuration().configure();

        //创建服务注册对象
        ServiceRegistry serviceRegistry =
                new ServiceRegistryBuilder()
        .applySettings(configuration.getProperties())
        .buildServiceRegistry();

        //创建sessionFactory
        SessionFactory sessionFactory = configuration.buildSessionFactory(serviceRegistry);

        //创建会话对象
        Session session = sessionFactory.getCurrentSession();
        //开启事务
        Transaction tx = session.beginTransaction();
        //生成一个学生身份证对象
        IdCard card = new IdCard("888888888888888888","刘德华");
        //生成一个学生对象
        Students stu = new Students(card,"男",new Date(),"计算机");
        //先保存被控表对象(身份证)
        session.save(card);
        session.save(stu);
        //提交事务
        tx.commit();

    }

7、添加学生Log：

2016-4-17 20:49:51 org.hibernate.annotations.common.Version <clinit>
INFO: HCANN000001: Hibernate Commons Annotations {4.0.2.Final}
2016-4-17 20:49:52 org.hibernate.Version logVersion
INFO: HHH000412: Hibernate Core {4.2.21.Final}
2016-4-17 20:49:52 org.hibernate.cfg.Environment <clinit>
INFO: HHH000206: hibernate.properties not found
2016-4-17 20:49:52 org.hibernate.cfg.Environment buildBytecodeProvider
INFO: HHH000021: Bytecode provider name : javassist
2016-4-17 20:49:52 org.hibernate.cfg.Configuration configure
INFO: HHH000043: Configuring from resource: /hibernate.cfg.xml
2016-4-17 20:49:52 org.hibernate.cfg.Configuration getConfigurationInputStream
INFO: HHH000040: Configuration resource: /hibernate.cfg.xml
2016-4-17 20:49:52 org.hibernate.cfg.Configuration doConfigure
INFO: HHH000041: Configured SessionFactory: null
2016-4-17 20:49:52 org.hibernate.service.jdbc.connections.internal.DriverManagerConnectionProviderImpl configure
WARN: HHH000402: Using Hibernate built-in connection pool (not for production use!)
2016-4-17 20:49:52 org.hibernate.service.jdbc.connections.internal.DriverManagerConnectionProviderImpl configure
INFO: HHH000115: Hibernate connection pool size: 20
2016-4-17 20:49:52 org.hibernate.service.jdbc.connections.internal.DriverManagerConnectionProviderImpl configure
INFO: HHH000006: Autocommit mode: false
2016-4-17 20:49:52 org.hibernate.service.jdbc.connections.internal.DriverManagerConnectionProviderImpl configure
INFO: HHH000401: using driver [com.mysql.jdbc.Driver] at URL [jdbc:mysql://localhost:3306/hibernate?useUnicode=true&characterEncoding=UTF-8]
2016-4-17 20:49:52 org.hibernate.service.jdbc.connections.internal.DriverManagerConnectionProviderImpl configure
INFO: HHH000046: Connection properties: {user=root, password=****}
2016-4-17 20:49:52 org.hibernate.dialect.Dialect <init>
INFO: HHH000400: Using dialect: org.hibernate.dialect.MySQLDialect
2016-4-17 20:49:52 org.hibernate.engine.jdbc.internal.LobCreatorBuilder useContextualLobCreation
INFO: HHH000423: Disabling contextual LOB creation as JDBC driver reported JDBC version [3] less than 4
2016-4-17 20:49:53 org.hibernate.engine.transaction.internal.TransactionFactoryInitiator initiateService
INFO: HHH000399: Using default transaction strategy (direct JDBC transactions)
2016-4-17 20:49:53 org.hibernate.hql.internal.ast.ASTQueryTranslatorFactory <init>
INFO: HHH000397: Using ASTQueryTranslatorFactory
2016-4-17 20:49:53 org.hibernate.tool.hbm2ddl.SchemaUpdate execute
INFO: HHH000228: Running hbm2ddl schema update
2016-4-17 20:49:53 org.hibernate.tool.hbm2ddl.SchemaUpdate execute
INFO: HHH000102: Fetching database metadata
2016-4-17 20:49:53 org.hibernate.tool.hbm2ddl.SchemaUpdate execute
INFO: HHH000396: Updating schema
2016-4-17 20:49:53 org.hibernate.tool.hbm2ddl.TableMetadata <init>
INFO: HHH000261: Table found: hibernate.idcard
2016-4-17 20:49:53 org.hibernate.tool.hbm2ddl.TableMetadata <init>
INFO: HHH000037: Columns: [pid, sname]
2016-4-17 20:49:53 org.hibernate.tool.hbm2ddl.TableMetadata <init>
INFO: HHH000108: Foreign keys: []
2016-4-17 20:49:53 org.hibernate.tool.hbm2ddl.TableMetadata <init>
INFO: HHH000126: Indexes: [primary]
2016-4-17 20:49:53 org.hibernate.tool.hbm2ddl.TableMetadata <init>
INFO: HHH000261: Table found: hibernate.students
2016-4-17 20:49:53 org.hibernate.tool.hbm2ddl.TableMetadata <init>
INFO: HHH000037: Columns: [birthday, sid, gender, pid, major]
2016-4-17 20:49:53 org.hibernate.tool.hbm2ddl.TableMetadata <init>
INFO: HHH000108: Foreign keys: [fk_mryi31xkbwbosevquurf60ivb]
2016-4-17 20:49:53 org.hibernate.tool.hbm2ddl.TableMetadata <init>
INFO: HHH000126: Indexes: [primary, fk_mryi31xkbwbosevquurf60ivb, uk_mryi31xkbwbosevquurf60ivb]
2016-4-17 20:49:53 org.hibernate.tool.hbm2ddl.SchemaUpdate execute
INFO: HHH000232: Schema update complete
Hibernate:
    insert
    into
        IdCard
        (sname, pid)
    values
        (?, ?)
Hibernate:
    insert
    into
        Students
        (birthday, pid, gender, major)
    values
        (?, ?, ?, ?)