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>