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>
