Java/Hibernate/Criteria Projection
Criteria: Projection Criteria
<source lang="java">
///////////////////////////////////////////////////////////////////////// import java.util.*; import java.sql.*; import org.hibernate.*; 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(); Session session = HibernateUtil.currentSession(); Criteria crit = session.createCriteria(Product.class); ProjectionList projList = Projections.projectionList(); projList.add(Projections.property("name")); projList.add(Projections.property("description")); crit.setProjection(projList); List results = crit.list(); displayObjectsList(results); HibernateUtil.checkData("select * from Supplier"); HibernateUtil.checkData("select * from Product"); } static public void displayObjectsList(List list) { Iterator iter = list.iterator(); if (!iter.hasNext()) { System.out.println("No objects to display."); return; } while (iter.hasNext()) { System.out.println("New object"); Object[] obj = (Object[]) iter.next(); for (int i=0;i<obj.length;i++) { System.out.println(obj[i]); } } }
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; }
}
///////////////////////////////////////////////////////////////////////// <?xml version="1.0" encoding="utf-8"?> <!DOCTYPE hibernate-mapping
PUBLIC "-//Hibernate/Hibernate Mapping DTD//EN" "http://hibernate.sourceforge.net/hibernate-mapping-3.0.dtd">
<hibernate-mapping>
<class name="Supplier"> <id name="id" type="int"> <generator class="increment"/> </id> <property name="name" type="string"/> <bag name="products" inverse="true" cascade="all,delete-orphan"> <key column="supplierId"/> <one-to-many class="Product"/> </bag>
</class>
</hibernate-mapping>
///////////////////////////////////////////////////////////////////////// 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>
Criteria: Row Count Criteria
<source lang="java">
///////////////////////////////////////////////////////////////////////// import java.util.*; import java.sql.*; import org.hibernate.*; 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(); Session session = HibernateUtil.currentSession(); Criteria crit = session.createCriteria(Product.class); crit.setProjection(Projections.rowCount()); List results = crit.list(); displayObjectList(results); HibernateUtil.checkData("select * from Supplier"); HibernateUtil.checkData("select * from Product"); } static public void displayObjectList(List list) { Iterator iter = list.iterator(); if (!iter.hasNext()) { System.out.println("No objects to display."); return; } while (iter.hasNext()) { Object obj = iter.next(); System.out.println(obj); } } 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; }
}
///////////////////////////////////////////////////////////////////////// <?xml version="1.0" encoding="utf-8"?> <!DOCTYPE hibernate-mapping
PUBLIC "-//Hibernate/Hibernate Mapping DTD//EN" "http://hibernate.sourceforge.net/hibernate-mapping-3.0.dtd">
<hibernate-mapping>
<class name="Supplier"> <id name="id" type="int"> <generator class="increment"/> </id> <property name="name" type="string"/> <bag name="products" inverse="true" cascade="all,delete-orphan"> <key column="supplierId"/> <one-to-many class="Product"/> </bag>
</class>
</hibernate-mapping>
/////////////////////////////////////////////////////////////////////////
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>