Java/Hibernate/Hibernate Session

Session Disconnect And Reconnect

   <source lang="java">

///////////////////////////////////////////////////////////////////////// import java.util.*; import java.sql.*; import org.hibernate.*; import org.hibernate.cfg.*; import org.hibernate.criterion.*; public class Main {

 public static void main(String[] args) {
   HibernateUtil.setup("create table Supplier ( id int, name VARCHAR);");
   HibernateUtil.setup("create table Product ( id int, name VARCHAR, description VARCHAR, price double,supplierId int);");
   
   prepareData();
       SessionFactory factory = new Configuration().configure().buildSessionFactory();
       Session session = factory.openSession();
       Query query = session.createQuery("from Product order by name");
       List list = query.list();
       Iterator i = list.iterator();
       while(i.hasNext()) {
          Product p = (Product)i.next();
          System.out.println(p.getName());
       }
       System.out.println("Step 1.");
       //session.close();
       
       session.disconnect();
       session.reconnect();
       query = session.createQuery("from Product order by name");
       list = query.list();
       i = list.iterator();
       while(i.hasNext()) {
          Product p = (Product)i.next();
          System.out.println(p.getName());
       }
       System.out.println("Step 2.");
   
       HibernateUtil.checkData("select * from Supplier");
       HibernateUtil.checkData("select * from Product");
 }
   static public void displaySupplierList(List list) {
       Iterator iter = list.iterator();
       if (!iter.hasNext()) {
           System.out.println("No suppliers to display.");
           return;
       }        
       while (iter.hasNext()) {
           Supplier supplier = (Supplier) iter.next();
           String msg = supplier.getName();
           System.out.println(msg);
       }
   }

 private static void prepareData(){
       Session session = HibernateUtil.currentSession();
       Supplier supplier1 = new Supplier();
       supplier1.setName("Supplier Name 1");
       session.save(supplier1);
       
       Supplier supplier2 = new Supplier();
       supplier2.setName("Supplier Name 2");
       session.save(supplier2);        
       
       Product product1 = new Product("Product 1","Name for Product 1", 2.0);
       product1.setSupplier(supplier1);
       supplier1.getProducts().add(product1);
       session.save(product1);
       
       Product product12 = new Product("Product 2","Name for Product 2", 22.0);
       product12.setSupplier(supplier1);
       supplier1.getProducts().add(product12);        
       session.save(product12);
       
       Product product2 = new Product("Product 3", "Name for Product 3", 30.0);
       product2.setSupplier(supplier2);
       supplier2.getProducts().add(product2);
       session.save(product2);
       
       session.flush();
       HibernateUtil.closeSession();
 }

}

///////////////////////////////////////////////////////////////////////// public class Product {

   private int id;
   private Supplier supplier;
   
   private String name;
   private String description;
   private double price;
   
   public Product()
   {
       super();
   }
   
   public Product(String name, String description, double price)
   {
       super();
       this.name = name;
       this.description = description;
       this.price = price;
   }
   
   public String getDescription()
   {
       return description;
   }
   public void setDescription(String description)
   {
       this.description = description;
   }
   public int getId()
   {
       return id;
   }
   public void setId(int id)
   {
       this.id = id;
   }
   public String getName()
   {
       return name;
   }
   public void setName(String name)
   {
       this.name = name;
   }

   public Supplier getSupplier()
   {
       return supplier;
   }
   public void setSupplier(Supplier supplier)
   {
       this.supplier = supplier;
   }
   
   public double getPrice()
   {
       return price;
   }
   public void setPrice(double price)
   {
       this.price = price;
   }

}

///////////////////////////////////////////////////////////////////////// import java.util.ArrayList; import java.util.List; public class Supplier {

   private int id;
   private String name;
   private List products = new ArrayList();
   
   public int getId()
   {
       return id;
   }
   public void setId(int id)
   {
       this.id = id;
   }
   public String getName()
   {
       return name;
   }
   public void setName(String name)
   {
       this.name = name;
   }
   public List getProducts()
   {
       return products;
   }
   public void setProducts(List products)
   {
       this.products = products;
   }

}

      </source>
   
  
 
  

Use Two Sessions

   <source lang="java">

///////////////////////////////////////////////////////////////////////// import java.util.*; import org.hibernate.*; import org.hibernate.criterion.*; public class Main {

 public static void main(String[] args) {
   HibernateUtil.setup("create table EVENTS ( uid int, name VARCHAR, start_Date date, duration int);");
   
   // hibernate code start
       HibernateFactory.buildSessionFactory();
       Session session = HibernateFactory.openSession();
       Session session2 = HibernateFactory.openSession();
       Event event = new Event();
       event.setName("Name");
       session.save(event);
       session.flush();
       Event event2 = (Event) session2.load(Event.class, event.getId());
       System.out.println(event2.getName());
       
       HibernateUtil.checkData("select uid, name from events");        
   // hibernate code end
 }
 

}

///////////////////////////////////////////////////////////////////////// <?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="Event" table="events">
       <id name="id" column="uid" type="long">
           <generator class="increment"/>
       </id>
       <property name="name" type="string"/>
       <property name="startDate" column="start_date" type="date"/>
       <property name="duration" type="integer"/>
   </class>

</hibernate-mapping>

///////////////////////////////////////////////////////////////////////// import java.io.Serializable; import java.util.Date; import java.util.Set; import java.util.LinkedHashSet; public class Event implements Serializable {

   private Long id;
   private int duration;
   private String name;
   private Date startDate;
   public Event() {
   }
   public Event(String name) {
       this.name = name;
   }
   /**
    * @hibernate.id generator-class="native" column="uid"
    * @return
    */
   public Long getId() { return id; }
   public void setId(Long id) { this.id = id; }
   /**
    * @hibernate.property column="name"
    * @return
    */
   public String getName() { return name; }
   public void setName(String name) { this.name = name;   }
   /**
    * @hibernate.property column="start_date"
    * @return
    */
   public Date getStartDate() { return startDate; }
   public void setStartDate(Date startDate) { this.startDate = startDate; }
   /**
    * @hibernate.property column="duration"
    * @return
    */
   public int getDuration() { return duration; }
   public void setDuration(int duration) { this.duration = duration; }

}

///////////////////////////////////////////////////////////////////////// /**

* Represents Exceptions thrown by the Data Access Layer.
*/

public class DataAccessLayerException extends RuntimeException {

   public DataAccessLayerException() {
   }
   public DataAccessLayerException(String message) {
       super(message);
   }
   public DataAccessLayerException(Throwable cause) {
       super(cause);
   }
   public DataAccessLayerException(String message, Throwable cause) {
       super(message, cause);
   }

}

      </source>