Hibernate 再接触 关系映射 一对一双向外键关联

凡是双向关联必设mapped by  由对方主导

wifi.java

package com.bjsxt.hibernate;

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

@Entity
public class Wife {
    private int id;
    private String name;
    private Husband husband;
    @OneToOne(mappedBy="wife")
    public Husband getHusband() {
        return husband;
    }
    public void setHusband(Husband husband) {
        this.husband = husband;
    }
    @Id
    @GeneratedValue
    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;
    }
    
}

Husband.java

package com.bjsxt.hibernate;

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

@Entity
public class Husband {
    private int id;
    private String name;
    private Wife wife;
    @Id
    @GeneratedValue
    public int getId() {
        return id;
    }
    
    public String getName() {
        return name;
    }
    @OneToOne
    @JoinColumn(name="wifeId")
    public Wife getWife() {
        return wife;
    }
    public void setId(int id) {
        this.id = id;
    }
    public void setName(String name) {
        this.name = name;
    }
    public void setWife(Wife wife) {
        this.wife = wife;
    }
    
}

测试类略

XML中

Student.java

package com.bjsxt.hibernate;

public class Student {
    
    private int id;
    private String name;
    
    private int age;
    private String sex;
    private boolean good;
    private StuIdCard stuIdCard;
    public StuIdCard getStuIdCard() {
        return stuIdCard;
    }
    public void setStuIdCard(StuIdCard stuIdCard) {
        this.stuIdCard = stuIdCard;
    }
    public boolean isGood() {
        return good;
    }
    public void setGood(boolean good) {
        this.good = good;
    }
    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 String getSex() {
        return sex;
    }
    public void setSex(String sex) {
        this.sex = sex;
    }
    
    
    
}

StuidCard.java

package com.bjsxt.hibernate;

public class StuIdCard {
    private int id;
    private String num;
    private Student student;
    public int getId() {
        return id;
    }
    public void setId(int id) {
        this.id = id;
    }
    public String getNum() {
        return num;
    }
    public void setNum(String num) {
        this.num = num;
    }
    public Student getStudent() {
        return student;
    }
    public void setStudent(Student student) {
        this.student = student;
    }
    
}

Student.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>
    <class name="com.bjsxt.hibernate.Student" dynamic-update="true">
        <id name="id">
            <generator class="native"></generator>
        </id>
        
        <property name="name"></property>
        <property name="age" />
        <property name="sex" />
        <property name="good" type="yes_no"></property>
        <one-to-one name="stuIdCard" property-ref="student"></one-to-one>
    </class>
    
</hibernate-mapping>

Stuidcard.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>
    <class name="com.bjsxt.hibernate.StuIdCard">
        <id name="id">
            <generator class="native"></generator>
        </id>
        
        <property name="num"/>
        <many-to-one name="student" column="studentId" unique="true"></many-to-one>
    </class>
    
</hibernate-mapping>

测试类代码略

单向 双向在数据库中实际山没区别，但利于编程

一对一单向主键关联（不重要）

Xml配置

略