Java/Hibernate/Class Hiearchy Mapping
Class Hierachy Mapping Table Per Class
<source lang="java">
///////////////////////////////////////////////////////////////////////// <?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="Book" table="cd" discriminator-value="cd"> <id name="id" type="integer" unsaved-value="0"> <generator class="increment"/> </id> <discriminator column="cd_type" type= "string"/> <property name="title"/> <property name="artist"/> <property name="purchasedate" type="date"/> <property name="cost" type="double"/> <subclass name="SpecialEditionBook" discriminator-value="SpecialEditionBook"> <property name="newfeatures" type="string"/> </subclass> <subclass name="InternationalBook" discriminator-value="InternationalBook"> <property name="languages"/> <property name="region"/> </subclass> </class> </hibernate-mapping>
///////////////////////////////////////////////////////////////////////// import java.io.*; import java.util.*;
public class Book { int id; String title; String artist; Date purchaseDate; double cost; public Book() { } public Book(String title, String artist, Date purchaseDate, double cost) { this.title = title; this.artist = artist; this.purchaseDate = purchaseDate; this.cost = cost; } public void setId(int id) { this.id = id; } public int getId(){ return id; } public void setTitle(String title) { this.title = title; } public String getTitle() { return title; } public void setArtist(String artist) { this.artist = artist; } public String getArtist() { return artist; } public void setPurchasedate(Date purchaseDate) { this.purchaseDate = purchaseDate; } public Date getPurchasedate() { return purchaseDate; } public void setCost(double cost) { this.cost = cost; } public double getCost() { return cost; } }
///////////////////////////////////////////////////////////////////////// <?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="Book.hbm.xml"/> </session-factory>
</hibernate-configuration> ///////////////////////////////////////////////////////////////////////// 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(" "); } }
}
/////////////////////////////////////////////////////////////////////////
import java.util.*; public class InternationalBook extends Book {
private String languages; private int region; public InternationalBook() { } public InternationalBook(String title, String artist, Date purchaseDate, double cost, String language, int region) { super(title, artist, purchaseDate, cost); languages = language; this.region = region; } public void setLanguages(String s) { languages = s; } public String getLanguages() { return languages; } public void setRegion(int i) { region = i; } public int getRegion() { return region; }
}
///////////////////////////////////////////////////////////////////////// log4j.rootCategory=WARN, console log4j.appender.console=org.apache.log4j.ConsoleAppender log4j.appender.console.layout=org.apache.log4j.PatternLayout log4j.appender.console.layout.ConversionPattern=%-4r [%t] %-5p %c %x - %m%n log4j.appender.stdout.Target=System.out
///////////////////////////////////////////////////////////////////////// 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 cd(id int,title varchar,artist varchar,purchasedate date,cost double,newfeatures varchar,languages varchar,region int,cd_type varchar);");
Session session = HibernateUtil.currentSession(); Book cd = new Book("Book", "R", new Date(), 9.99); SpecialEditionBook secd = new SpecialEditionBook("sBook", "R", new Date(), 9.99, "W"); InternationalBook icd = new InternationalBook("IBook", "R", new Date(), 9.99, "S", 4); session.save(cd); session.save(secd); session.save(icd); session.flush(); session.close(); HibernateUtil.checkData("select * from cd"); }
}
///////////////////////////////////////////////////////////////////////// import java.util.*; public class SpecialEditionBook extends Book {
private String newfeatures; public SpecialEditionBook() { } public SpecialEditionBook(String title, String artist, Date purchaseDate, double cost, String features) { super(title, artist, purchaseDate, cost); newfeatures = features; } public void setNewfeatures(String s) { newfeatures = s; } public String getNewfeatures() { return newfeatures; }
}
</source>
Class Hierarchy Mapping Table Per Concrete Class
<source lang="java">
///////////////////////////////////////////////////////////////////////// import java.io.*; import java.util.*;
public class Book { int id; String title; String artist; Date purchaseDate; double cost; public Book() { } public Book(String title, String artist, Date purchaseDate, double cost) { this.title = title; this.artist = artist; this.purchaseDate = purchaseDate; this.cost = cost; } public void setId(int id) { this.id = id; } public int getId(){ return id; } public void setTitle(String title) { this.title = title; } public String getTitle() { return title; } public void setArtist(String artist) { this.artist = artist; } public String getArtist() { return artist; } public void setPurchasedate(Date purchaseDate) { this.purchaseDate = purchaseDate; } public Date getPurchasedate() { return purchaseDate; } public void setCost(double cost) { this.cost = cost; } public double getCost() { return cost; } }
///////////////////////////////////////////////////////////////////////// <?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="Book.hbm.xml"/> </session-factory>
</hibernate-configuration>
///////////////////////////////////////////////////////////////////////// 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(" "); } }
}
///////////////////////////////////////////////////////////////////////// import java.util.*; public class InternationalBook extends Book {
private String languages; private int region; public InternationalBook() { } public InternationalBook(String title, String artist, Date purchaseDate, double cost, String language, int region) { super(title, artist, purchaseDate, cost); languages = language; this.region = region; } public void setLanguages(String s) { languages = s; } public String getLanguages() { return languages; } public void setRegion(int i) { region = i; } public int getRegion() { return region; }
}
/////////////////////////////////////////////////////////////////////////
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 cd(id int,title varchar,artist varchar,purchasedate date,cost double);"); HibernateUtil.setup("create table secd(id int,title varchar,artist varchar,purchasedate date,cost double,newfeatures varchar);"); HibernateUtil.setup("create table icd(id int,title varchar,artist varchar,purchasedate date,cost double,languages varchar,region int);");
Session session = HibernateUtil.currentSession(); Book cd = new Book("Book", "R", new Date(), 9.99); SpecialEditionBook secd = new SpecialEditionBook("sBook", "R", new Date(), 9.99, "W"); InternationalBook icd = new InternationalBook("IBook", "R", new Date(), 9.99, "S", 4); session.save(cd); session.save(secd); session.save(icd); session.flush(); session.close(); HibernateUtil.checkData("select * from cd"); HibernateUtil.checkData("select * from secd"); HibernateUtil.checkData("select * from icd"); }
}
///////////////////////////////////////////////////////////////////////// import java.util.*; public class SpecialEditionBook extends Book {
private String newfeatures; public SpecialEditionBook() { } public SpecialEditionBook(String title, String artist, Date purchaseDate, double cost, String features) { super(title, artist, purchaseDate, cost); newfeatures = features; } public void setNewfeatures(String s) { newfeatures = s; } public String getNewfeatures() { return newfeatures; }
}
///////////////////////////////////////////////////////////////////////// <?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="Book" table="cd" discriminator-value="cd"> <id name="id" type="integer" unsaved-value="0"> <generator class="increment"/> </id> <property name="title"/> <property name="artist"/> <property name="purchasedate" type="date"/> <property name="cost" type="double"/> </class> <class name="SpecialEditionBook" table="secd"> <id name="id" type="integer" unsaved-value="0"> <generator class="increment"/> </id> <property name="title"/> <property name="artist"/> <property name="purchasedate" type="date"/> <property name="cost" type="double"/> <property name="newfeatures" type="string"/> </class> <class name="InternationalBook" table="icd"> <id name="id" type="integer" unsaved-value="0"> <generator class="increment"/> </id> <property name="title"/> <property name="artist"/> <property name="purchasedate" type="date"/> <property name="cost" type="double"/> <property name="languages"/> <property name="region"/> </class>
</hibernate-mapping>
/////////////////////////////////////////////////////////////////////////
</source>
ClassHierchy Mapping Table Per Sub class
<source lang="java">
///////////////////////////////////////////////////////////////////////// <?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="Book" table="cd"> <id name="id" type="integer" unsaved-value="0"> <generator class="increment"/> </id> <property name="title"/> <property name="artist"/> <property name="purchasedate" type="date"/> <property name="cost" type="double"/> <joined-subclass name="SpecialEditionBook" table="secd"> <key column="id"/> <property name="newfeatures" type="string"/> </joined-subclass> <joined-subclass name="InternationalBook" table="icd"> <key column="id"/> <property name="languages"/> <property name="region"/> </joined-subclass> </class>
</hibernate-mapping>
/////////////////////////////////////////////////////////////////////////
import java.io.*;
import java.util.*;
public class Book { int id; String title; String artist; Date purchaseDate; double cost; public Book() { } public Book(String title, String artist, Date purchaseDate, double cost) { this.title = title; this.artist = artist; this.purchaseDate = purchaseDate; this.cost = cost; } public void setId(int id) { this.id = id; } public int getId(){ return id; } public void setTitle(String title) { this.title = title; } public String getTitle() { return title; } public void setArtist(String artist) { this.artist = artist; } public String getArtist() { return artist; } public void setPurchasedate(Date purchaseDate) { this.purchaseDate = purchaseDate; } public Date getPurchasedate() { return purchaseDate; } public void setCost(double cost) { this.cost = cost; } public double getCost() { return cost; } }
///////////////////////////////////////////////////////////////////////// <?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="Book.hbm.xml"/> </session-factory>
</hibernate-configuration> ///////////////////////////////////////////////////////////////////////// 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(" "); } }
}
/////////////////////////////////////////////////////////////////////////
import java.util.*; public class InternationalBook extends Book {
private String languages; private int region; public InternationalBook() { } public InternationalBook(String title, String artist, Date purchaseDate, double cost, String language, int region) { super(title, artist, purchaseDate, cost); languages = language; this.region = region; } public void setLanguages(String s) { languages = s; } public String getLanguages() { return languages; } public void setRegion(int i) { region = i; } public int getRegion() { return region; }
}
///////////////////////////////////////////////////////////////////////// log4j.rootCategory=WARN, console log4j.appender.console=org.apache.log4j.ConsoleAppender log4j.appender.console.layout=org.apache.log4j.PatternLayout log4j.appender.console.layout.ConversionPattern=%-4r [%t] %-5p %c %x - %m%n log4j.appender.stdout.Target=System.out
///////////////////////////////////////////////////////////////////////// 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 cd(id int,title varchar,artist varchar,purchasedate date,cost double);"); HibernateUtil.setup("create table secd(id int,newfeatures varchar);"); HibernateUtil.setup("create table icd(id int,languages varchar,region int);"); Session session = HibernateUtil.currentSession(); Book cd = new Book("Book", "R", new Date(), 9.99); SpecialEditionBook secd = new SpecialEditionBook("sBook", "R", new Date(), 9.99, "W"); InternationalBook icd = new InternationalBook("IBook", "R", new Date(), 9.99, "S", 4); session.save(cd); session.save(secd); session.save(icd); session.flush(); session.close(); HibernateUtil.checkData("select * from cd"); }
}
///////////////////////////////////////////////////////////////////////// import java.util.*; public class SpecialEditionBook extends Book {
private String newfeatures; public SpecialEditionBook() { } public SpecialEditionBook(String title, String artist, Date purchaseDate, double cost, String features) { super(title, artist, purchaseDate, cost); newfeatures = features; } public void setNewfeatures(String s) { newfeatures = s; } public String getNewfeatures() { return newfeatures; }
}
</source>