hibernate 建表一对一 就是一对多，多的一方外键唯一unique

Person.java

 package cn.itcast.hiberate.sh.domain.onetoone;

 import java.io.Serializable;
 import java.util.Set;

 public class Person implements Serializable{
     private Long cid;
     private String cname;
     private String description;

     public Long getCid() {
         return cid;
     }

     public void setCid(Long cid) {
         this.cid = cid;
     }

     public String getCname() {
         return cname;
     }

     public void setCname(String cname) {
         this.cname = cname;
     }

     public String getDescription() {
         return description;
     }

     public void setDescription(String description) {
         this.description = description;
     }

     public Address getAddress() {
         return address;
     }

     public void setAddress(Address address) {
         this.address = address;
     }

     private Address address;
 }

Person.hbm.xml

 <?xml version="1.0" encoding="utf-8"?>
 <!DOCTYPE hibernate-mapping PUBLIC "-//Hibernate/Hibernate Mapping DTD 3.0//EN"
 "http://hibernate.sourceforge.net/hibernate-mapping-3.0.dtd">
 <hibernate-mapping>
     <class name="cn.itcast.hiberate.sh.domain.Classes">
         <id name="cid" length="5" type="java.lang.Long">
             <generator class="increment"></generator>
         </id>
         <property name="cname" length="20" type="java.lang.String"></property>

         <property name="description" length="100" type="java.lang.String"></property>
         <!--
             set元素对应类中的set集合
             通过set元素使classes表与student表建立关联
                key是通过外键的形式让两张表建立关联
                one-to-many是通过类的形式让两个类建立关联

             cascade 级联
                save-update
                    1、当 保存班级的时候，对学生进行怎么样的操作
                         如果学生对象在数据库中没有对应的值，这个时候会执行save操作
                         如果学生对象在数据库中有对应的值，这个时候会执行update操作
                delete
                all
             inverse  维护关系
                true      不维护关系
                false     维护关系
                default   false
          -->
         <set name="students" cascade="save-update" inverse="true">
             <!--
                 key是用来描述外键
              -->
             <key>
                 <column name="cid"></column>
             </key>
             <one-to-many class="cn.itcast.hiberate.sh.domain.Student"/>
         </set>
     </class>
 </hibernate-mapping>

Address.java

 package cn.itcast.hiberate.sh.domain.onetoone;

 import java.io.Serializable;

 public class Address implements Serializable{
     private Long sid;
     private String sname;

     private Person person;

     public Person getPerson() {
         return person;
     }
     public void setPerson(Person person) {
         this.person = person;
     }
     public Long getSid() {
         return sid;
     }
     public void setSid(Long sid) {
         this.sid = sid;
     }
     public String getSname() {
         return sname;
     }
     public void setSname(String sname) {
         this.sname = sname;
     }
     public String getDescription() {
         return description;
     }
     public void setDescription(String description) {
         this.description = description;
     }
     private String description;
 }

Address.hbm.xml  外键唯一

 <?xml version="1.0" encoding="utf-8"?>
 <!DOCTYPE hibernate-mapping PUBLIC "-//Hibernate/Hibernate Mapping DTD 3.0//EN"
 "http://hibernate.sourceforge.net/hibernate-mapping-3.0.dtd">
 <hibernate-mapping>
     <class name="cn.itcast.hiberate.sh.domain.Student">
         <id name="sid" length="5">
             <generator class="increment"></generator>
         </id>
         <property name="sname" length="20"></property>
         <property name="description" length="100"></property>
         <!--
             多对一
               column 外键
          -->
         <many-to-one name="classes" class="cn.itcast.hiberate.sh.domain.Classes" column="cid" cascade="save-update" unique="true"></many-to-one>
     </class>
 </hibernate-mapping>