Java/Hibernate/Hibernate Transaction
Hibernate Transaction With Try Catch
<source lang="java">
///////////////////////////////////////////////////////////////////////// import java.io.Serializable; import java.util.*; import org.hibernate.*; import org.hibernate.cfg.*; import org.hibernate.criterion.*; import org.hibernate.event.*; import org.hibernate.event.def.*; public class Main {
public static void main(String[] args) throws Exception { HibernateUtil.setup("create table grouptable (id int,name varchar);"); HibernateUtil.setup("create table story (id int,info varchar,idx int,parent_id int);"); Session session = HibernateUtil.currentSession(); Group sp = new Group("Group Name"); ArrayList list = new ArrayList(); list.add(new Story("Story Name 1")); list.add(new Story("Story Name 2")); sp.setStories(list); Transaction transaction = null; try { transaction = session.beginTransaction(); session.save(sp); transaction.rumit(); } catch (Exception e) { if (transaction != null) { transaction.rollback(); throw e; } } finally { session.close(); } HibernateUtil.checkData("select * from grouptable"); HibernateUtil.checkData("select * from story"); }
}
///////////////////////////////////////////////////////////////////////// import java.util.*; public class Story {
private int id; private String info; public Story(){ } public Story(String info) { this.info = info; } public void setId(int i) { id = i; } public int getId() { return id; } public void setInfo(String n) { info = n; } public String getInfo() { return info; }
}
///////////////////////////////////////////////////////////////////////// import java.util.*; public class Group {
private int id; private String name; private List stories; public Group(){ } public Group(String name) { this.name = name; } public void setId(int i) { id = i; } public int getId() { return id; } public void setName(String n) { name = n; } public String getName() { return name; } public void setStories(List l) { stories = l; } public List getStories() { return stories; }
}
///////////////////////////////////////////////////////////////////////// <?xml version="1.0" encoding="UTF-8"?> <!DOCTYPE hibernate-mapping
PUBLIC "-//Hibernate/Hibernate Mapping DTD//EN" "http://hibernate.sourceforge.net/hibernate-mapping-2.0.dtd">
<hibernate-mapping>
<class name="Group" table="grouptable"> <id name="id" unsaved-value="0"> <generator class="increment"/> </id> <list name="stories" cascade="all"> <key column="parent_id"/> <index column="idx"/> <one-to-many class="Story"/> </list> <property name="name" type="string"/> </class> <class name="Story" table="story"> <id name="id" unsaved-value="0"> <generator class="increment"/> </id> <property name="info"/> </class>
</hibernate-mapping>
///////////////////////////////////////////////////////////////////////// import java.sql.Connection; import java.sql.DriverManager; import java.sql.Statement; import java.sql.ResultSet; import java.sql.ResultSetMetaData; import org.hibernate.HibernateException; import org.hibernate.Session; import org.hibernate.SessionFactory; import org.hibernate.cfg.Configuration; public class HibernateUtil {
public static final SessionFactory sessionFactory; static { try { // Create the SessionFactory from hibernate.cfg.xml sessionFactory = new Configuration().configure().buildSessionFactory(); } catch (Throwable ex) { // Make sure you log the exception, as it might be swallowed System.err.println("Initial SessionFactory creation failed." + ex); throw new ExceptionInInitializerError(ex); } } public static final ThreadLocal session = new ThreadLocal(); public static Session currentSession() throws HibernateException { Session s = (Session) session.get(); // Open a new Session, if this thread has none yet if (s == null) { s = sessionFactory.openSession(); // Store it in the ThreadLocal variable session.set(s); } return s; } public static void closeSession() throws HibernateException { Session s = (Session) session.get(); if (s != null) s.close(); session.set(null); } static Connection conn; static Statement st; public static void setup(String sql) { try { // Step 1: Load the JDBC driver. Class.forName("org.hsqldb.jdbcDriver"); System.out.println("Driver Loaded."); // Step 2: Establish the connection to the database. String url = "jdbc:hsqldb:data/tutorial"; conn = DriverManager.getConnection(url, "sa", ""); System.out.println("Got Connection."); st = conn.createStatement(); st.executeUpdate(sql); } catch (Exception e) { System.err.println("Got an exception! "); e.printStackTrace(); System.exit(0); } } public static void checkData(String sql) { try { HibernateUtil.outputResultSet(st .executeQuery(sql));
// conn.close();
} catch (Exception e) { e.printStackTrace(); } } public static void outputResultSet(ResultSet rs) throws Exception{ ResultSetMetaData metadata = rs.getMetaData(); int numcols = metadata.getColumnCount(); String[] labels = new String[numcols]; int[] colwidths = new int[numcols]; int[] colpos = new int[numcols]; int linewidth; for (int i = 0; i < numcols; i++) { labels[i] = metadata.getColumnLabel(i + 1); // get its label System.out.print(labels[i]+" "); } System.out.println("------------------------"); while (rs.next()) { for (int i = 0; i < numcols; i++) { Object value = rs.getObject(i + 1); if(value == null){ System.out.print(" "); }else{ System.out.print(value.toString().trim()+" "); } } System.out.println(" "); } }
}
///////////////////////////////////////////////////////////////////////// <?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="connection.driver_class">org.hsqldb.jdbcDriver</property> <property name="connection.url">jdbc:hsqldb:data/tutorial</property> <property name="connection.username">sa</property> <property name="connection.password"></property> <property name="connection.pool_size">1</property> <property name="dialect">org.hibernate.dialect.HSQLDialect</property> <property name="show_sql">true</property> <mapping resource="Group.hbm.xml"/> </session-factory>
</hibernate-configuration>
</source>
Transaction Rollback Illustration
<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(); Product p = null; Session session = factory.openSession(); Transaction tx = session.beginTransaction(); p = (Product)session.createQuery("from Product where name="Product 1"").uniqueResult(); tx.rumit(); System.out.println("Username of p acquired from DB... " + p.getName()); System.out.println("Begin transaction:"); tx = session.beginTransaction(); System.out.println("Change name of p"); p.setName("quentin"); System.out.println("Username of p before rollback... " + p.getName()); tx.rollback(); System.out.println("Username of p after rollback... " + p.getName()); tx = session.beginTransaction(); System.out.println("About to refresh p!"); session.refresh(p); System.out.println("Username of p after refresh... " + p.getName()); tx.rumit(); System.out.println("Username of p after commit... " + p.getName()); 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; }
}
/////////////////////////////////////////////////////////////////////////
<?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; }
}
///////////////////////////////////////////////////////////////////////// <?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="connection.driver_class">org.hsqldb.jdbcDriver</property> <property name="connection.url">jdbc:hsqldb:data/tutorial</property> <property name="connection.username">sa</property> <property name="connection.password"></property> <property name="connection.pool_size">1</property> <property name="dialect">org.hibernate.dialect.HSQLDialect</property> <property name="show_sql">true</property> <mapping resource="Product.hbm.xml"/> <mapping resource="Supplier.hbm.xml"/> </session-factory>
</hibernate-configuration>
</source>