Hibernate一对一数据关联(二) 唯一外键关联

Hibernate一对一数据关联(二) 唯一外键关联
一.单向一对一关联
1.数据模型如下图所示：


2.数据表sql
DROP   TABLE  T_User;
DROP   TABLE  T_Group;

CREATE   TABLE  T_Group (
       id  INT   NOT   NULL  AUTO_INCREMENT
     , name  VARCHAR ( 50 )
     ,  PRIMARY   KEY  (id)
);

CREATE   TABLE  T_User (
       id  INT   NOT   NULL  AUTO_INCREMENT
     , name  VARCHAR ( 50 )
     , age  INT
     , group_id  INT   NOT   NULL
     ,  PRIMARY   KEY  (id)
     ,  INDEX  (group_id)
     ,  CONSTRAINT  FK_T_User_1  FOREIGN   KEY  (group_id)
                   REFERENCES  T_Group (id)
);

</DIV>
3.POJO类
TUser.java
package  cn.blogjava.start;

public   class  TUser   implements  java.io.Serializable {
     //  Fields    
      private  Integer id;
      private  Integer age;
      private  String name;
      private  TGroup group;


     //  Constructors

     public  Integer getAge() {
         return  age;
    }

     public   void  setAge(Integer age) {
         this .age  =  age;
    }


     public  TGroup getGroup() {
         return  group;
    }

     public   void  setGroup(TGroup group) {
         this .group  =  group;
    }

     /**  default constructor  */
     public  TUser() {
    }
    
     /**  constructor with id  */
     public  TUser(Integer id) {
         this .id  =  id;
    }

     //  Property accessors

     public  Integer getId() {
         return   this .id;
    }
    
     public   void  setId(Integer id) {
         this .id  =  id;
    }

     public  String getName() {
         return   this .name;
    }
    
     public   void  setName(String name) {
         this .name  =  name;
    }
}
TGroup.java
package  cn.blogjava.start;

import  java.io.Serializable;

public   class  TGroup  implements  Serializable {
    
     private  Integer id;
     private  String name;
    
     public  Integer getId() {
         return  id;
    }
     public   void  setId(Integer id) {
         this .id  =  id;
    }
     public  String getName() {
         return  name;
    }
     public   void  setName(String name) {
         this .name  =  name;
    }
    
}
</DIV>
3.配置文件
hibernate.cfg.xml
<? xml version="1.0" encoding="UTF-8" ?>
<! DOCTYPE hibernate-configuration PUBLIC
        "-//Hibernate/Hibernate Configuration DTD 3.0//EN"
        "http://hibernate.sourceforge.net/hibernate-configuration-3.0.dtd" >
< hibernate-configuration >
     < session-factory >
         < property  name ="hibernate.connection.driver_class" > com.mysql.jdbc.Driver </ property >
         < property  name ="hibernate.connection.password" > 1234 </ property >
         < property  name ="hibernate.connection.url" > jdbc:mysql://localhost:3306/sample </ property >
         < property  name ="hibernate.connection.username" > root </ property >
         < property  name ="hibernate.dialect" > org.hibernate.dialect.MySQLDialect </ property >
         < mapping  resource ="cn/blogjava/start/TUser.hbm.xml"   />
         < mapping  resource ="cn/blogjava/start/TGroup.hbm.xml"   />         
     </ session-factory >
</ hibernate-configuration >
</DIV>
TGroup.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 ="cn.blogjava.start.TGroup"  table ="T_Group"  catalog ="sample" >
         < id  name ="id"  type ="integer" >
             < column  name ="id"   />
             < generator  class ="native"   />
         </ id >
         < property  name ="name"  type ="string"  column ="name"   />
     </ class >
</ hibernate-mapping >
</DIV>
TUser.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 ="cn.blogjava.start.TUser"  table ="T_User"  catalog ="sample" >
         < id  name ="id"  type ="integer" >
             < column  name ="id"   />
             < generator  class ="native"   />
         </ id >
         < property  name ="name"  type ="string" >
             < column  name ="name"  length ="100"  not-null ="true"   />
         </ property >
         < property  name ="age"  type ="java.lang.Integer"  column ="age"   />
         < many-to-one  name ="group"  
                    class ="cn.blogjava.start.TGroup"  
                    column ="GROUP_ID"
                    cascade="all"
                    unique ="true"  
          />
     </ class >
</ hibernate-mapping >
</DIV>
4.测试代码
package cn.blogjava.start;

import java.util.List;

import junit.framework.Assert;
import junit.framework.TestCase;

import org.hibernate.HibernateException;
import org.hibernate.Session;
import org.hibernate.SessionFactory;
import org.hibernate.Transaction;
import org.hibernate.cfg.Configuration;


public class HibernateTest extends TestCase {
    
    Session session = null;

    protected void setUp() {
        try {
            Configuration config = new Configuration().configure();
            SessionFactory sessionFactory = config.buildSessionFactory();
            session = sessionFactory.openSession();
            
        } catch (HibernateException e) {
            e.printStackTrace();
        }        
    }

    protected void tearDown() {
        try {
            session.close();        
        } catch (HibernateException e) {
            e.printStackTrace();
        }        
    }    
    
    /**
     * 对象持久化测试(Insert方法)
     */        
    public void testInsert() {
        Transaction tran = null;
        try {
        
            TUser user = new TUser();
            user.setName("byf");
            user.setAge(new Integer(26));
            
            TGroup group = new TGroup();
            group.setName("Admin");
            
               // 如果在配置文件中没有cascade="all",就要先插入group信息
           // tran = session.beginTransaction();            
           // session.save(group);
           // session.flush();
           // tran.commit();
                        
            tran = session.beginTransaction();                    
            //设置关联
            user.setGroup(group);

               //插入user信息
            session.save(user);
            session.flush();
            tran.commit();
            Assert.assertEquals(user.getId().intValue()>0 ,true);
        } catch (HibernateException e) {
            e.printStackTrace();
            Assert.fail(e.getMessage());
            if(tran != null) {
                try {
                    tran.rollback();
                } catch (Exception e1) {
                    e1.printStackTrace();
                }
            }
        }
    }
    
    /**
     * 对象读取测试(Select方法)
     */            
    public void testSelect(){
        String hql = " from TUser where name='byf'";
        try {
            List userList = session.createQuery(hql).list();
            TUser user = (TUser)userList.get(0);
            System.out.println("user name is " + user.getName());
            System.out.println("user group is " + user.getGroup().getName());
            Assert.assertEquals(user.getName(), "byf");
        } catch (Exception e) {
            e.printStackTrace();
            Assert.fail(e.getMessage());
        }
    }
}