Hibernate逍遥游记-第12章 映射值类型集合-001映射set(<element>)

1.

2.

<?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="mypack.Monkey" table="MONKEYS" >
    <id name="id" type="long" column="ID">
      <generator class="increment"/>
    </id>

    <property name="name" type="string" >
        <column name="NAME" length="15" />
    </property>

   <property name="age" type="int" >
        <column name="AGE" />
   </property>

   <set   name="images"   table="IMAGES"    lazy="true" >
        <key column="MONKEY_ID" />
        <element column="FILENAME" type="string"  not-null="true"/>
   </set>   

  </class>
 
</hibernate-mapping>

3.

package mypack;

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

public class Monkey implements Serializable {
    private Long id;
    private String name;
    private int age;
    private Set images=new TreeSet();

    /** full constructor */
    public Monkey(String name, int age,Set images) {
        this.name = name;
        this.age=age;
        this.images = images;
    }

    /** default constructor */
    public Monkey() {
    }

    /** minimal constructor */
    public Monkey(Set images) {
        this.images = images;
    }

    public Long getId() {
        return this.id;
    }

    public void setId(Long id) {
        this.id = id;
    }

    public String getName() {
        return this.name;
    }

    public void setName(String name) {
        this.name = name;
    }

    public int getAge() {
        return this.age;
    }

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

    public Set getImages() {
        return this.images;
    }

    public void setImages(Set images) {
        this.images = images;
    }

}

4.

package mypack;

import org.hibernate.*;
import org.hibernate.cfg.Configuration;
import java.util.*;
import java.sql.*;

public class BusinessService{
  public static SessionFactory sessionFactory;
  static{
     try{
      Configuration config = new Configuration().configure();
      sessionFactory = config.buildSessionFactory();
    }catch(RuntimeException e){e.printStackTrace();throw e;}

  }

  public void saveMonkey(Monkey monkey){
      Session session = sessionFactory.openSession();
      Transaction tx = null;
      List results=new ArrayList();
      try {
       tx = session.beginTransaction();
       session.save(monkey);
       tx.commit();
    }catch (RuntimeException e) {
      if (tx != null) {
        tx.rollback();
      }
      throw e;
    } finally {
      session.close();
    }
  }

  public Monkey loadMonkey(long id){
      Session session = sessionFactory.openSession();
      Transaction tx = null;
      try {
       tx = session.beginTransaction();
       Monkey monkey=(Monkey)session.get(Monkey.class,new Long(id));
       Hibernate.initialize(monkey.getImages());
       tx.commit();
      return monkey;
    }catch (RuntimeException e) {
      if (tx != null) {
        tx.rollback();
      }
      throw e;
    } finally {
      session.close();
    }
  }

   public void test() {
      Set images=new HashSet();
      images.add("image1.jpg");
      images.add("image4.jpg");
      images.add("image2.jpg");
      images.add("image5.jpg");
      
      Monkey monkey=new Monkey("Tom",21,images);
      saveMonkey(monkey);
      
      monkey=loadMonkey(1);
      printMonkey(monkey);  

  }

  private void printMonkey(Monkey monkey){
     System.out.println(monkey.getImages().getClass().getName());
     Iterator it=monkey.getImages().iterator();
     while(it.hasNext()){
        String fileName=(String)it.next();
        System.out.println(monkey.getName()+" "+fileName);
     }
  }
  public static void main(String args[]){
    new BusinessService().test();
    sessionFactory.close();
  }
}

drop database if exists SAMPLEDB;
create database SAMPLEDB;
use SAMPLEDB;

create table MONKEYS (
   ID bigint not null,
   NAME varchar(15),
   AGE int, 
   primary key (ID)
);

create table IMAGES(
   MONKEY_ID bigint not null,
   FILENAME varchar(15) not null,
   primary key (MONKEY_ID,FILENAME)
);

alter table IMAGES add index IDX_MONKEY(MONKEY_ID), add constraint FK_MONKEY foreign key (MONKEY_ID) references MONKEYS(ID);

5.

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

<hibernate-configuration>
    <session-factory>
        <property name="dialect">
            org.hibernate.dialect.MySQLDialect
        </property>
        <property name="connection.driver_class">
            com.mysql.jdbc.Driver
        </property>
        <property name="connection.url">
            jdbc:mysql://localhost:3306/sampledb
        </property>
        <property name="connection.username">
            root
        </property>
        <property name="connection.password">
            1234
        </property>

        <property name="show_sql">true</property>

        <mapping resource="mypack/Monkey.hbm.xml" />
    </session-factory>
</hibernate-configuration>