两种不同方式的一对一映射关系：

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1）配置文件：

hibernate.cfg.xml

     
         
              
               
       
        com.mysql.jdbc.Driver
               
       
        jdbc:mysql://127.0.0.1/testdb
               
       
        root
               
               
               
       
        1
               
               
       
        org.hibernate.dialect.MySQL5Dialect
               
               
       
        thread
               
               
       
        org.hibernate.cache.internal.NoCacheProvider
               
               
       
        true
               
               
       
        update
               
               
               
           
      
     

 

Employer.hbm.xml

 

Address.hbm.xml

     
         
              
                   
                        
         employer            
                
               
               
           
      
     

 

Detial.hbm.xml

 

2）Java bean:

package com.my.bean;import java.util.Date;public class Employer {    private long id;    private String companyName;    private Date createTime;    private Address address;    private Detial detial;        public long getId() {        return id;    }    public void setId(long id) {        this.id = id;    }    public String getCompanyName() {        return companyName;    }    public void setCompanyName(String companyName) {        this.companyName = companyName;    }    public Date getCreateTime() {        return createTime;    }    public void setCreateTime(Date createTime) {        this.createTime = createTime;    }    public Address getAddress() {        return address;    }    public void setAddress(Address address) {        this.address = address;    }    public Detial getDetial() {        return detial;    }    public void setDetial(Detial detial) {        this.detial = detial;    }    }

package com.my.bean;public class Address {    private long id;    private String location;    private Employer employer;        public long getId() {        return id;    }    public void setId(long id) {        this.id = id;    }    public String getLocation() {        return location;    }    public void setLocation(String location) {        this.location = location;    }    public Employer getEmployer() {        return employer;    }    public void setEmployer(Employer employer) {        this.employer = employer;    }    }

package com.my.bean;public class Detial {    private long id;    private String info;    private Employer employer;        public long getId() {        return id;    }    public void setId(long id) {        this.id = id;    }    public String getInfo() {        return info;    }    public void setInfo(String info) {        this.info = info;    }    public Employer getEmployer() {        return employer;    }    public void setEmployer(Employer employer) {        this.employer = employer;    }}

 

3）测试：

package com.my.init;import java.util.Date;import java.util.HashSet;import java.util.List;import java.util.Set;import javax.xml.soap.Detail;import org.hibernate.Query;import org.hibernate.Session;import org.hibernate.Transaction;import com.my.bean.Address;import com.my.bean.Detial;import com.my.bean.Employer;import com.my.bean.User;import com.my.bean.UserAccount;import com.my.dao.util.HibernateUtil;public class Test {    @SuppressWarnings("unchecked")    public static void main(String[] args) {        Session session = HibernateUtil.getSessionFactory().openSession();        Transaction tx = session.beginTransaction();                // new employer        Employer employer = new Employer();        employer.setCompanyName("my company");        employer.setCreateTime(new Date());                // new address        Address address = new Address();        address.setLocation("china");                // new detail        Detial detail = new Detial();        detail.setInfo("info");                // add relation        employer.setAddress(address);        employer.setDetial(detail);        address.setEmployer(employer);        detail.setEmployer(employer);                session.save(employer);        session.save(address);        session.save(detail);                // Get employer        String hsqlSelect = "from Employer";        Query query = session.createQuery(hsqlSelect);        List
     
       es = query.list();        if(es != null && es.size() > 0){            Employer e = es.get(0);            System.out.println(e.getCompanyName());            System.out.println(e.getDetial().getInfo());        }                tx.commit();        session.close();    }}
     

 

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关注点：

1）Employer.hbm.xml

这个generator的class="native"值有好几种，具体使用方法可参见：

这里有两个one-to-one，两种一对一的不同映射方式。

其中第二种one-to-one中有一个属性引用，对应的是在detial中的employer属性。

property-ref的使用说明可参见：

 

2）Address.hbm.xml

         
              
       employer    
      
     

这是声明一个外部键字段的一对一关系用法。

这里这个contrained设为true是必需的。

 

3）Detial.hbm.xml

这是一对一关系的另一种现实方式，使用的是many-to-one，但unique设为true是必需的。

 

这两种不同的一对一关系映射，参考资料：