Java/JPA/One to One Mapping
Содержание
BiDirection One To One Mappoing
<source lang="java">
File: Address.java import javax.persistence.CascadeType; import javax.persistence.Entity; import javax.persistence.Id; import javax.persistence.OneToOne; @Entity public class Address {
@Id private int id; private String street; private String city; private String state; private String zip; @OneToOne(cascade=CascadeType.ALL) private Student student; public int getId() { return id; } public void setId(int id) { this.id = id; } public String getStreet() { return street; } public void setStreet(String address) { this.street = address; } public String getCity() { return city; } public void setCity(String city) { this.city = city; } public String getState() { return state; } public void setState(String state) { this.state = state; } public String getZip() { return zip; } public void setZip(String zip) { this.zip = zip; } public Student getStudent() { return student; } public void setStudent(Student student) { this.student = student; } public String toString() { return "Address id: " + getId() + ", street: " + getStreet() + ", city: " + getCity() + ", state: " + getState() + ", zip: " + getZip(); }
}
File: Helper.java import java.sql.Connection; import java.sql.DriverManager; import java.sql.ResultSet; import java.sql.ResultSetMetaData; import java.sql.Statement; public class Helper {
public static void checkData() throws Exception { Class.forName("org.hsqldb.jdbcDriver"); Connection conn = DriverManager.getConnection("jdbc:hsqldb:data/tutorial", "sa", ""); Statement st = conn.createStatement(); ResultSet mrs = conn.getMetaData().getTables(null, null, null, new String[] { "TABLE" }); while (mrs.next()) { String tableName = mrs.getString(3); System.out.println("\n\n\n\nTable Name: "+ tableName); ResultSet rs = st.executeQuery("select * from " + tableName); ResultSetMetaData metadata = rs.getMetaData(); while (rs.next()) { System.out.println(" Row:"); for (int i = 0; i < metadata.getColumnCount(); i++) { System.out.println(" Column Name: "+ metadata.getColumnLabel(i + 1)+ ", "); System.out.println(" Column Type: "+ metadata.getColumnTypeName(i + 1)+ ": "); Object value = rs.getObject(i + 1); System.out.println(" Column Value: "+value+"\n"); } } } }
}
File: Main.java import java.util.List; import javax.persistence.EntityManager; import javax.persistence.EntityManagerFactory; import javax.persistence.Persistence; import javax.persistence.Query; public class Main {
static EntityManagerFactory emf = Persistence.createEntityManagerFactory("JPAService"); static EntityManager em = emf.createEntityManager(); public static void main(String[] a) throws Exception { em.getTransaction().begin(); Student student = new Student(); student.setName("Joe"); Address address = new Address(); address.setCity("city"); address.setStudent(student); //em.persist(address); student.setAddress(address); em.persist(student); em.flush(); em.getTransaction().rumit(); Query query = em.createQuery("SELECT e FROM Address e"); List<Address> list = (List<Address>) query.getResultList(); System.out.println(list.get(0).getStudent()); em.close(); emf.close(); Helper.checkData(); }
}
File: Student.java import javax.persistence.CascadeType; import javax.persistence.Entity; import javax.persistence.Id; import javax.persistence.OneToOne; @Entity public class Student {
@Id private int id; private String name; @OneToOne(cascade=CascadeType.ALL) private Address address; 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 Address getAddress() { return address; } public void setAddress(Address address) { this.address = address; } public String toString() { return "\n\nID:" + id + "\nName:" + name + "\n\n"; }
}
File: persistence.xml
<persistence xmlns="http://java.sun.ru/xml/ns/persistence"
xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xsi:schemaLocation="http://java.sun.ru/xml/ns/persistence http://java.sun.ru/xml/ns/persistence/persistence" version="1.0"> <persistence-unit name="JPAService" transaction-type="RESOURCE_LOCAL"> <properties> <property name="hibernate.dialect" value="org.hibernate.dialect.HSQLDialect"/> <property name="hibernate.hbm2ddl.auto" value="update"/> <property name="hibernate.connection.driver_class" value="org.hsqldb.jdbcDriver"/> <property name="hibernate.connection.username" value="sa"/> <property name="hibernate.connection.password" value=""/> <property name="hibernate.connection.url" value="jdbc:hsqldb:data/tutorial"/> </properties> </persistence-unit>
</persistence>
</source>
Mark Entity RelationShip As One To One
<source lang="java">
File: Address.java import javax.persistence.Entity; import javax.persistence.GeneratedValue; import javax.persistence.GenerationType; import javax.persistence.Id; import javax.persistence.TableGenerator; @Entity public class Address {
@TableGenerator(name = "Address_Gen", table = "ID_GEN", pkColumnName = "GEN_NAME", valueColumnName = "GEN_VAL", pkColumnValue = "Addr_Gen", initialValue = 10000, allocationSize = 100) @Id @GeneratedValue(strategy = GenerationType.TABLE, generator = "Address_Gen") private int id; private String street; private String city; private String state; private String zip; public int getId() { return id; } public void setId(int id) { this.id = id; } public String getStreet() { return street; } public void setStreet(String address) { this.street = address; } public String getCity() { return city; } public void setCity(String city) { this.city = city; } public String getState() { return state; } public void setState(String state) { this.state = state; } public String getZip() { return zip; } public void setZip(String zip) { this.zip = zip; } public String toString() { return "Address id: " + getId() + ", street: " + getStreet() + ", city: " + getCity() + ", state: " + getState() + ", zip: " + getZip(); }
}
File: Professor.java import javax.persistence.Entity; import javax.persistence.GeneratedValue; import javax.persistence.GenerationType; import javax.persistence.Id; import javax.persistence.OneToOne; import javax.persistence.TableGenerator; @Entity public class Professor {
@TableGenerator(name = "Emp_Gen", table = "ID_GEN", pkColumnName = "GEN_NAME", valueColumnName = "GEN_VAL") @Id @GeneratedValue(strategy = GenerationType.TABLE, generator = "Emp_Gen") private int id; private String name; private long salary; @OneToOne private Address address; 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 long getSalary() { return salary; } public void setSalary(long salary) { this.salary = salary; } public Address getAddress() { return address; } public void setAddress(Address address) { this.address = address; } public String toString() { return "Professor id: " + getId() + " name: " + getName() + " salary: " + getSalary(); }
}
File: ProfessorService.java import java.util.Collection; import javax.persistence.EntityManager; import javax.persistence.Query; public class ProfessorService {
protected EntityManager em; public ProfessorService(EntityManager em) { this.em = em; }
public Professor createProfessor(String name, long salary, String street, String city, String state, String zip) { Professor emp = new Professor(); emp.setName(name); emp.setSalary(salary); Address addr = new Address(); addr.setStreet(street); addr.setCity(city); addr.setState(state); addr.setZip(zip); emp.setAddress(addr); em.persist(emp); em.persist(addr); return emp; } public void removeProfessor(int id) { Professor emp = findProfessor(id); if (emp != null) { em.remove(emp); } } public Professor raiseProfessorSalary(int id, long raise) { Professor emp = em.find(Professor.class, id); if (emp != null) { emp.setSalary(emp.getSalary() + raise); } return emp; } public Professor findProfessor(int id) { return em.find(Professor.class, id); } public Collection<Professor> findAllProfessors() { Query query = em.createQuery("SELECT e FROM Professor e"); return (Collection<Professor>) query.getResultList(); }
}
File: JPAUtil.java import java.io.Reader; import java.sql.Connection; import java.sql.DriverManager; import java.sql.ResultSet; import java.sql.ResultSetMetaData; import java.sql.Statement; public class JPAUtil {
Statement st; public JPAUtil() throws Exception{ Class.forName("org.hsqldb.jdbcDriver"); System.out.println("Driver Loaded."); String url = "jdbc:hsqldb:data/tutorial"; Connection conn = DriverManager.getConnection(url, "sa", ""); System.out.println("Got Connection."); st = conn.createStatement(); } public void executeSQLCommand(String sql) throws Exception { st.executeUpdate(sql); } public void checkData(String sql) throws Exception { ResultSet rs = st.executeQuery(sql); ResultSetMetaData metadata = rs.getMetaData(); for (int i = 0; i < metadata.getColumnCount(); i++) { System.out.print("\t"+ metadata.getColumnLabel(i + 1)); } System.out.println("\n----------------------------------"); while (rs.next()) { for (int i = 0; i < metadata.getColumnCount(); i++) { Object value = rs.getObject(i + 1); if (value == null) { System.out.print("\t "); } else { System.out.print("\t"+value.toString().trim()); } } System.out.println(""); } }
}
File: Main.java import javax.persistence.EntityManager; import javax.persistence.EntityManagerFactory; import javax.persistence.Persistence; public class Main {
public static void main(String[] a) throws Exception { JPAUtil util = new JPAUtil(); EntityManagerFactory emf = Persistence.createEntityManagerFactory("ProfessorService"); EntityManager em = emf.createEntityManager(); ProfessorService service = new ProfessorService(em); em.getTransaction().begin(); Professor emp = service.createProfessor("name", 100, "street", "city", "state", "zip"); em.getTransaction().rumit(); System.out.println("Persisted " + emp); util.checkData("select * from Professor"); util.checkData("select * from ADDRESS"); util.checkData("select * from ID_GEN"); em.close(); emf.close(); }
}
File: persistence.xml <persistence xmlns="http://java.sun.ru/xml/ns/persistence"
xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xsi:schemaLocation="http://java.sun.ru/xml/ns/persistence http://java.sun.ru/xml/ns/persistence/persistence" version="1.0"> <persistence-unit name="JPAService" transaction-type="RESOURCE_LOCAL"> <properties> <property name="hibernate.dialect" value="org.hibernate.dialect.HSQLDialect"/> <property name="hibernate.hbm2ddl.auto" value="update"/> <property name="hibernate.connection.driver_class" value="org.hsqldb.jdbcDriver"/> <property name="hibernate.connection.username" value="sa"/> <property name="hibernate.connection.password" value=""/> <property name="hibernate.connection.url" value="jdbc:hsqldb:data/tutorial"/> </properties> </persistence-unit>
</persistence>
</source>
One To One Bidirectional
<source lang="java">
File: ParkingSpace.java
import javax.persistence.Entity; import javax.persistence.GeneratedValue; import javax.persistence.GenerationType; import javax.persistence.Id; import javax.persistence.OneToOne; @Entity public class ParkingSpace {
@Id @GeneratedValue(strategy=GenerationType.IDENTITY) private int id; private int lot; private String location; @OneToOne(mappedBy="parkingSpace") private Professor employee; public int getId() { return id; } public void setId(int id) { this.id = id; } public int getLot() { return lot; } public void setLot(int lot) { this.lot = lot; } public String getLocation() { return location; } public void setLocation(String deptName) { this.location = deptName; } public String toString() { return "ParkingSpace id: " + getId() + " lot: " + getLot() + ", location: " + getLocation(); }
}
File: Professor.java
import javax.persistence.Entity; import javax.persistence.GeneratedValue; import javax.persistence.GenerationType; import javax.persistence.Id; import javax.persistence.JoinColumn; import javax.persistence.OneToOne; @Entity public class Professor {
@Id @GeneratedValue(strategy=GenerationType.IDENTITY) private int id; private String name; private long salary; @OneToOne @JoinColumn(name="PSPACE_ID") private ParkingSpace parkingSpace; 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 long getSalary() { return salary; } public void setSalary(long salary) { this.salary = salary; } public ParkingSpace getParkingSpace() { return parkingSpace; } public void setParkingSpace(ParkingSpace parkingSpace) { this.parkingSpace = parkingSpace; } public String toString() { return "Professor id: " + getId() + " name: " + getName() + " with " + getParkingSpace(); }
}
File: ProfessorService.java import java.util.Collection; import javax.persistence.EntityManager; import javax.persistence.Query; public class ProfessorService {
protected EntityManager em; public ProfessorService(EntityManager em) { this.em = em; } public Professor createProfessor(String name, long salary) { Professor emp = new Professor(); emp.setName(name); emp.setSalary(salary); em.persist(emp); return emp; } public Professor setProfessorParkingSpace(int empId, int spaceId) { Professor emp = em.find(Professor.class, empId); ParkingSpace pSpace = em.find(ParkingSpace.class, spaceId); emp.setParkingSpace(pSpace); return emp; } public Collection<Professor> findAllProfessors() { Query query = em.createQuery("SELECT e FROM Professor e"); return (Collection<Professor>) query.getResultList(); } public ParkingSpace createParkingSpace(int lot, String location) { ParkingSpace space = new ParkingSpace(); space.setLot(lot); space.setLocation(location); em.persist(space); return space; } public Collection<ParkingSpace> findAllParkingSpaces() { Query query = em.createQuery("SELECT p FROM ParkingSpace p"); return (Collection<ParkingSpace>) query.getResultList(); }
}
File: JPAUtil.java import java.io.Reader; import java.sql.Connection; import java.sql.DriverManager; import java.sql.ResultSet; import java.sql.ResultSetMetaData; import java.sql.Statement; public class JPAUtil {
Statement st; public JPAUtil() throws Exception{ Class.forName("org.hsqldb.jdbcDriver"); System.out.println("Driver Loaded."); String url = "jdbc:hsqldb:data/tutorial"; Connection conn = DriverManager.getConnection(url, "sa", ""); System.out.println("Got Connection."); st = conn.createStatement(); } public void executeSQLCommand(String sql) throws Exception { st.executeUpdate(sql); } public void checkData(String sql) throws Exception { ResultSet rs = st.executeQuery(sql); ResultSetMetaData metadata = rs.getMetaData(); for (int i = 0; i < metadata.getColumnCount(); i++) { System.out.print("\t"+ metadata.getColumnLabel(i + 1)); } System.out.println("\n----------------------------------"); while (rs.next()) { for (int i = 0; i < metadata.getColumnCount(); i++) { Object value = rs.getObject(i + 1); if (value == null) { System.out.print("\t "); } else { System.out.print("\t"+value.toString().trim()); } } System.out.println(""); } }
}
File: Main.java import java.util.Collection; import javax.persistence.EntityManager; import javax.persistence.EntityManagerFactory; import javax.persistence.Persistence; public class Main {
public static void main(String[] a) throws Exception { JPAUtil util = new JPAUtil(); EntityManagerFactory emf = Persistence.createEntityManagerFactory("ProfessorService"); EntityManager em = emf.createEntityManager(); ProfessorService service = new ProfessorService(em); em.getTransaction().begin(); Professor emp = service.createProfessor("empName", 100); ParkingSpace pSpace = service.createParkingSpace(1, "location"); Professor emp1 = service.setProfessorParkingSpace(emp.getId(), pSpace.getId()); Collection<Professor> emps = service.findAllProfessors(); if (emps.isEmpty()) { System.out.println("No Professors found "); } else { System.out.println("Found Professors: "); for (Professor emp2 : emps) { System.out.println(emp2); } } Collection<ParkingSpace> pSpaces = service.findAllParkingSpaces(); if (pSpaces.isEmpty()) { System.out.println("No ParkingSpaces found "); } else { System.out.println("Found ParkingSpaces:"); for (ParkingSpace pSpace1 : pSpaces) { System.out.println(pSpace1); } } util.checkData("select * from Professor"); util.checkData("select * from ParkingSpace"); em.getTransaction().rumit(); em.close(); emf.close(); }
}
File: persistence.xml
<persistence xmlns="http://java.sun.ru/xml/ns/persistence"
xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xsi:schemaLocation="http://java.sun.ru/xml/ns/persistence http://java.sun.ru/xml/ns/persistence/persistence" version="1.0"> <persistence-unit name="JPAService" transaction-type="RESOURCE_LOCAL"> <properties> <property name="hibernate.dialect" value="org.hibernate.dialect.HSQLDialect"/> <property name="hibernate.hbm2ddl.auto" value="update"/> <property name="hibernate.connection.driver_class" value="org.hsqldb.jdbcDriver"/> <property name="hibernate.connection.username" value="sa"/> <property name="hibernate.connection.password" value=""/> <property name="hibernate.connection.url" value="jdbc:hsqldb:data/tutorial"/> </properties> </persistence-unit>
</persistence>
</source>
One To One MappedBy
<source lang="java">
File: ParkingSpace.java
import javax.persistence.Entity; import javax.persistence.Id; import javax.persistence.OneToOne; import javax.persistence.PrimaryKeyJoinColumn; import javax.persistence.Table; @Entity public class ParkingSpace {
@Id private int id; private int lot; private String location; @OneToOne @PrimaryKeyJoinColumn private Professor employee; public int getId() { return id; } public void setId(int id) { this.id = id; } public int getLot() { return lot; } public void setLot(int lot) { this.lot = lot; } public String getLocation() { return location; } public void setLocation(String deptName) { this.location = deptName; } public Professor getProfessor() { return employee; } public void setProfessor(Professor employee) { this.employee = employee; } public String toString() { return "ParkingSpace id: " + getId() + " lot: " + getLot() + ", location: " + getLocation(); }
}
File: Professor.java
import javax.persistence.Entity; import javax.persistence.Id; import javax.persistence.OneToOne; @Entity public class Professor {
@Id private int id; private String name; private long salary; @OneToOne(mappedBy="employee") private ParkingSpace parkingSpace; 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 long getSalary() { return salary; } public void setSalary(long salary) { this.salary = salary; } public ParkingSpace getParkingSpace() { return parkingSpace; } public void setParkingSpace(ParkingSpace parkingSpace) { this.parkingSpace = parkingSpace; } public String toString() { return "Professor id: " + getId() + " name: " + getName() + " with " + getParkingSpace(); }
}
File: ProfessorService.java import java.util.Collection; import javax.persistence.EntityManager; import javax.persistence.Query; public class ProfessorService {
protected EntityManager em; public ProfessorService(EntityManager em) { this.em = em; } public Professor createProfessor(int id, String name, long salary) { Professor emp = new Professor(); emp.setId(id); emp.setName(name); emp.setSalary(salary); em.persist(emp); return emp; } public Collection<Professor> findAllProfessors() { Query query = em.createQuery("SELECT e FROM Professor e"); return (Collection<Professor>) query.getResultList(); } public ParkingSpace createParkingSpace(Professor emp, int lot, String location) { ParkingSpace space = new ParkingSpace(); space.setId(emp.getId()); space.setLot(lot); space.setLocation(location); emp.setParkingSpace(space); space.setProfessor(emp); em.persist(space); return space; } public Collection<ParkingSpace> findAllParkingSpaces() { Query query = em.createQuery("SELECT p FROM ParkingSpace p"); return (Collection<ParkingSpace>) query.getResultList(); }
}
File: JPAUtil.java import java.io.Reader; import java.sql.Connection; import java.sql.DriverManager; import java.sql.ResultSet; import java.sql.ResultSetMetaData; import java.sql.Statement; public class JPAUtil {
Statement st; public JPAUtil() throws Exception{ Class.forName("org.hsqldb.jdbcDriver"); System.out.println("Driver Loaded."); String url = "jdbc:hsqldb:data/tutorial"; Connection conn = DriverManager.getConnection(url, "sa", ""); System.out.println("Got Connection."); st = conn.createStatement(); } public void executeSQLCommand(String sql) throws Exception { st.executeUpdate(sql); } public void checkData(String sql) throws Exception { ResultSet rs = st.executeQuery(sql); ResultSetMetaData metadata = rs.getMetaData(); for (int i = 0; i < metadata.getColumnCount(); i++) { System.out.print("\t"+ metadata.getColumnLabel(i + 1)); } System.out.println("\n----------------------------------"); while (rs.next()) { for (int i = 0; i < metadata.getColumnCount(); i++) { Object value = rs.getObject(i + 1); if (value == null) { System.out.print("\t "); } else { System.out.print("\t"+value.toString().trim()); } } System.out.println(""); } }
}
File: Main.java import java.util.Collection; import javax.persistence.EntityManager; import javax.persistence.EntityManagerFactory; import javax.persistence.Persistence; public class Main {
public static void main(String[] a) throws Exception { JPAUtil util = new JPAUtil(); EntityManagerFactory emf = Persistence.createEntityManagerFactory("ProfessorService"); EntityManager em = emf.createEntityManager(); ProfessorService service = new ProfessorService(em); em.getTransaction().begin(); Professor emp = service.createProfessor(1, "empName", 100L); service.createParkingSpace(emp, 1, "location"); System.out.println("Created " + emp); Collection<Professor> emps = service.findAllProfessors(); if (emps.isEmpty()) { System.out.println("No Professors found "); } else { System.out.println("Found Professors:"); for (Professor emp1 : emps) { System.out.println(emp1); } } Collection<ParkingSpace> pSpaces = service.findAllParkingSpaces(); if (pSpaces.isEmpty()) { System.out.println("No ParkingSpaces found "); } else { System.out.println("Found ParkingSpaces:"); for (ParkingSpace pSpace : pSpaces) { System.out.println(pSpace); } } util.checkData("select * from Professor"); util.checkData("select * from ParkingSpace"); em.getTransaction().rumit(); em.close(); emf.close(); }
}
File: persistence.xml
<persistence xmlns="http://java.sun.ru/xml/ns/persistence"
xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xsi:schemaLocation="http://java.sun.ru/xml/ns/persistence http://java.sun.ru/xml/ns/persistence/persistence" version="1.0"> <persistence-unit name="JPAService" transaction-type="RESOURCE_LOCAL"> <properties> <property name="hibernate.dialect" value="org.hibernate.dialect.HSQLDialect"/> <property name="hibernate.hbm2ddl.auto" value="update"/> <property name="hibernate.connection.driver_class" value="org.hsqldb.jdbcDriver"/> <property name="hibernate.connection.username" value="sa"/> <property name="hibernate.connection.password" value=""/> <property name="hibernate.connection.url" value="jdbc:hsqldb:data/tutorial"/> </properties> </persistence-unit>
</persistence>
</source>
One To One Mapping Based On Table Based ID
<source lang="java">
File: Address.java import javax.persistence.Entity; import javax.persistence.GeneratedValue; import javax.persistence.GenerationType; import javax.persistence.Id; import javax.persistence.TableGenerator; @Entity public class Address {
@TableGenerator(name = "Address_Gen", table = "ID_GEN", pkColumnName = "GEN_NAME", valueColumnName = "GEN_VAL", pkColumnValue = "Addr_Gen", initialValue = 10000, allocationSize = 100) @Id @GeneratedValue(strategy = GenerationType.TABLE, generator = "Address_Gen") private int id; private String street; private String city; private String state; private String zip; public int getId() { return id; } public void setId(int id) { this.id = id; } public String getStreet() { return street; } public void setStreet(String address) { this.street = address; } public String getCity() { return city; } public void setCity(String city) { this.city = city; } public String getState() { return state; } public void setState(String state) { this.state = state; } public String getZip() { return zip; } public void setZip(String zip) { this.zip = zip; } public String toString() { return "Address id: " + getId() + ", street: " + getStreet() + ", city: " + getCity() + ", state: " + getState() + ", zip: " + getZip(); }
}
File: Student.java import javax.persistence.Entity; import javax.persistence.GeneratedValue; import javax.persistence.GenerationType; import javax.persistence.Id; import javax.persistence.OneToOne; import javax.persistence.TableGenerator; @Entity public class Student {
@TableGenerator(name = "Emp_Gen", table = "ID_GEN", pkColumnName = "GEN_NAME", valueColumnName = "GEN_VAL") @Id @GeneratedValue(strategy = GenerationType.TABLE, generator = "Emp_Gen") private int id; private String name; @OneToOne private Address address; 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 Address getAddress() { return address; } public void setAddress(Address address) { this.address = address; } public String toString() { return "\n\nID:" + id + "\nName:" + name + "\n\n"; }
}
File: Main.java import java.sql.Timestamp; import java.util.List; import java.util.UUID; import javax.persistence.EntityManager; import javax.persistence.EntityManagerFactory; import javax.persistence.Persistence; import javax.persistence.Query; public class Main {
static EntityManagerFactory emf = Persistence.createEntityManagerFactory("JPAService"); static EntityManager em = emf.createEntityManager(); public static void main(String[] a) throws Exception { em.getTransaction().begin(); Student student = new Student(); student.setName("Joe"); Address address = new Address(); em.persist(address); student.setAddress(address); em.persist(student); em.flush(); em.getTransaction().rumit(); Query query = em.createQuery("SELECT e FROM Student e"); List<Student> list = (List<Student>) query.getResultList(); System.out.println(list); em.close(); emf.close(); Helper.checkData(); }
}
File: Helper.java import java.sql.Connection; import java.sql.DriverManager; import java.sql.ResultSet; import java.sql.ResultSetMetaData; import java.sql.Statement; public class Helper {
public static void checkData() throws Exception { Class.forName("org.hsqldb.jdbcDriver"); Connection conn = DriverManager.getConnection("jdbc:hsqldb:data/tutorial", "sa", ""); Statement st = conn.createStatement(); ResultSet mrs = conn.getMetaData().getTables(null, null, null, new String[] { "TABLE" }); while (mrs.next()) { String tableName = mrs.getString(3); System.out.println("\n\n\n\nTable Name: "+ tableName); ResultSet rs = st.executeQuery("select * from " + tableName); ResultSetMetaData metadata = rs.getMetaData(); while (rs.next()) { System.out.println(" Row:"); for (int i = 0; i < metadata.getColumnCount(); i++) { System.out.println(" Column Name: "+ metadata.getColumnLabel(i + 1)+ ", "); System.out.println(" Column Type: "+ metadata.getColumnTypeName(i + 1)+ ": "); Object value = rs.getObject(i + 1); System.out.println(" Column Value: "+value+"\n"); } } } }
}
File: persistence.xml
<persistence xmlns="http://java.sun.ru/xml/ns/persistence"
xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xsi:schemaLocation="http://java.sun.ru/xml/ns/persistence http://java.sun.ru/xml/ns/persistence/persistence" version="1.0"> <persistence-unit name="JPAService" transaction-type="RESOURCE_LOCAL"> <properties> <property name="hibernate.dialect" value="org.hibernate.dialect.HSQLDialect"/> <property name="hibernate.hbm2ddl.auto" value="update"/> <property name="hibernate.connection.driver_class" value="org.hsqldb.jdbcDriver"/> <property name="hibernate.connection.username" value="sa"/> <property name="hibernate.connection.password" value=""/> <property name="hibernate.connection.url" value="jdbc:hsqldb:data/tutorial"/> </properties> </persistence-unit>
</persistence>
</source>
One To One Mapping: Lazy load
<source lang="java">
File: ParkingSpace.java
import javax.persistence.Entity; import javax.persistence.GeneratedValue; import javax.persistence.GenerationType; import javax.persistence.Id; import javax.persistence.Table; @Entity public class ParkingSpace {
@Id @GeneratedValue(strategy=GenerationType.IDENTITY) private int id; private int lot; private String location; public int getId() { return id; } public void setId(int id) { this.id = id; } public int getLot() { return lot; } public void setLot(int lot) { this.lot = lot; } public String getLocation() { return location; } public void setLocation(String deptName) { this.location = deptName; } public String toString() { return "ParkingSpace id: " + getId() + " lot: " + getLot() + ", location: " + getLocation(); }
}
File: Professor.java
import static javax.persistence.FetchType.LAZY; import javax.persistence.Entity; import javax.persistence.GeneratedValue; import javax.persistence.GenerationType; import javax.persistence.Id; import javax.persistence.OneToOne; @Entity public class Professor {
@Id @GeneratedValue(strategy=GenerationType.IDENTITY) private int id; private String name; private long salary; @OneToOne(fetch=LAZY) private ParkingSpace parkingSpace; 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 long getSalary() { return salary; } public void setSalary(long salary) { this.salary = salary; } public ParkingSpace getParkingSpace() { return parkingSpace; } public void setParkingSpace(ParkingSpace parkingSpace) { this.parkingSpace = parkingSpace; } public String toString() { return "Professor id: " + getId() + " name: " + getName() + " with " + getParkingSpace(); }
}
File: ProfessorService.java import java.util.Collection; import javax.persistence.EntityManager; import javax.persistence.Query; public class ProfessorService {
protected EntityManager em; public ProfessorService(EntityManager em) { this.em = em; } public Professor createProfessor(String name, long salary) { Professor emp = new Professor(); emp.setName(name); emp.setSalary(salary); em.persist(emp); return emp; } public Professor setProfessorParkingSpace(int empId, int spaceId) { Professor emp = em.find(Professor.class, empId); ParkingSpace pSpace = em.find(ParkingSpace.class, spaceId); emp.setParkingSpace(pSpace); return emp; } public Collection<Professor> findAllProfessors() { Query query = em.createQuery("SELECT e FROM Professor e"); return (Collection<Professor>) query.getResultList(); } public ParkingSpace createParkingSpace(int lot, String location) { ParkingSpace space = new ParkingSpace(); space.setLot(lot); space.setLocation(location); em.persist(space); return space; } public Collection<ParkingSpace> findAllParkingSpaces() { Query query = em.createQuery("SELECT p FROM ParkingSpace p"); return (Collection<ParkingSpace>) query.getResultList(); }
}
File: JPAUtil.java import java.io.Reader; import java.sql.Connection; import java.sql.DriverManager; import java.sql.ResultSet; import java.sql.ResultSetMetaData; import java.sql.Statement; public class JPAUtil {
Statement st; public JPAUtil() throws Exception{ Class.forName("org.hsqldb.jdbcDriver"); System.out.println("Driver Loaded."); String url = "jdbc:hsqldb:data/tutorial"; Connection conn = DriverManager.getConnection(url, "sa", ""); System.out.println("Got Connection."); st = conn.createStatement(); } public void executeSQLCommand(String sql) throws Exception { st.executeUpdate(sql); } public void checkData(String sql) throws Exception { ResultSet rs = st.executeQuery(sql); ResultSetMetaData metadata = rs.getMetaData(); for (int i = 0; i < metadata.getColumnCount(); i++) { System.out.print("\t"+ metadata.getColumnLabel(i + 1)); } System.out.println("\n----------------------------------"); while (rs.next()) { for (int i = 0; i < metadata.getColumnCount(); i++) { Object value = rs.getObject(i + 1); if (value == null) { System.out.print("\t "); } else { System.out.print("\t"+value.toString().trim()); } } System.out.println(""); } }
}
File: Main.java import java.util.Collection; import javax.persistence.EntityManager; import javax.persistence.EntityManagerFactory; import javax.persistence.Persistence; public class Main {
public static void main(String[] a) throws Exception { JPAUtil util = new JPAUtil(); EntityManagerFactory emf = Persistence.createEntityManagerFactory("ProfessorService"); EntityManager em = emf.createEntityManager(); ProfessorService service = new ProfessorService(em); em.getTransaction().begin(); Professor emp = service.createProfessor("empName", 100L); ParkingSpace pSpace = service.createParkingSpace(1, "location"); emp = service.setProfessorParkingSpace(emp.getId(), pSpace.getId()); Collection<Professor> emps = service.findAllProfessors(); if (emps.isEmpty()) { System.out.println("No Professors found "); } else { System.out.println("Found Professors:"); for (Professor emp1 : emps) { System.out.println(emp1); } } Collection<ParkingSpace> pSpaces = service.findAllParkingSpaces(); if (pSpaces.isEmpty()) { System.out.println("No ParkingSpaces found "); } else { System.out.println("Found ParkingSpaces:"); for (ParkingSpace pSpace1 : pSpaces) { System.out.println(pSpace1); } } util.checkData("select * from Professor"); util.checkData("select * from ParkingSpace"); em.getTransaction().rumit(); em.close(); emf.close(); }
}
File: persistence.xml
<persistence xmlns="http://java.sun.ru/xml/ns/persistence"
xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xsi:schemaLocation="http://java.sun.ru/xml/ns/persistence http://java.sun.ru/xml/ns/persistence/persistence" version="1.0"> <persistence-unit name="JPAService" transaction-type="RESOURCE_LOCAL"> <properties> <property name="hibernate.dialect" value="org.hibernate.dialect.HSQLDialect"/> <property name="hibernate.hbm2ddl.auto" value="update"/> <property name="hibernate.connection.driver_class" value="org.hsqldb.jdbcDriver"/> <property name="hibernate.connection.username" value="sa"/> <property name="hibernate.connection.password" value=""/> <property name="hibernate.connection.url" value="jdbc:hsqldb:data/tutorial"/> </properties> </persistence-unit>
</persistence>
</source>
One To One Unidirectional Mapping
<source lang="java">
File: ParkingSpace.java
import javax.persistence.Entity; import javax.persistence.GeneratedValue; import javax.persistence.GenerationType; import javax.persistence.Id; import javax.persistence.Table; @Entity public class ParkingSpace {
@Id @GeneratedValue(strategy=GenerationType.IDENTITY) private int id; private int lot; private String location; public int getId() { return id; } public void setId(int id) { this.id = id; } public int getLot() { return lot; } public void setLot(int lot) { this.lot = lot; } public String getLocation() { return location; } public void setLocation(String deptName) { this.location = deptName; } public String toString() { return "ParkingSpace id: " + getId() + " lot: " + getLot() + ", location: " + getLocation(); }
}
File: Professor.java
import javax.persistence.Entity; import javax.persistence.GeneratedValue; import javax.persistence.GenerationType; import javax.persistence.Id; import javax.persistence.JoinColumn; import javax.persistence.OneToOne; @Entity public class Professor {
@Id @GeneratedValue(strategy=GenerationType.IDENTITY) private int id; private String name; private long salary; @OneToOne @JoinColumn(name="PSPACE_ID") private ParkingSpace parkingSpace; 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 long getSalary() { return salary; } public void setSalary(long salary) { this.salary = salary; } public ParkingSpace getParkingSpace() { return parkingSpace; } public void setParkingSpace(ParkingSpace parkingSpace) { this.parkingSpace = parkingSpace; } public String toString() { return "Professor id: " + getId() + " name: " + getName() + " with " + getParkingSpace(); }
}
File: ProfessorService.java import java.util.Collection; import javax.persistence.EntityManager; import javax.persistence.Query; public class ProfessorService {
protected EntityManager em; public ProfessorService(EntityManager em) { this.em = em; } public Professor createProfessor(String name, long salary) { Professor emp = new Professor(); emp.setName(name); emp.setSalary(salary); em.persist(emp); return emp; } public Professor setProfessorParkingSpace(int empId, int spaceId) { Professor emp = em.find(Professor.class, empId); ParkingSpace pSpace = em.find(ParkingSpace.class, spaceId); emp.setParkingSpace(pSpace); return emp; } public Collection<Professor> findAllProfessors() { Query query = em.createQuery("SELECT e FROM Professor e"); return (Collection<Professor>) query.getResultList(); } public ParkingSpace createParkingSpace(int lot, String location) { ParkingSpace space = new ParkingSpace(); space.setLot(lot); space.setLocation(location); em.persist(space); return space; } public Collection<ParkingSpace> findAllParkingSpaces() { Query query = em.createQuery("SELECT p FROM ParkingSpace p"); return (Collection<ParkingSpace>) query.getResultList(); }
}
File: JPAUtil.java import java.io.Reader; import java.sql.Connection; import java.sql.DriverManager; import java.sql.ResultSet; import java.sql.ResultSetMetaData; import java.sql.Statement; public class JPAUtil {
Statement st; public JPAUtil() throws Exception{ Class.forName("org.hsqldb.jdbcDriver"); System.out.println("Driver Loaded."); String url = "jdbc:hsqldb:data/tutorial"; Connection conn = DriverManager.getConnection(url, "sa", ""); System.out.println("Got Connection."); st = conn.createStatement(); } public void executeSQLCommand(String sql) throws Exception { st.executeUpdate(sql); } public void checkData(String sql) throws Exception { ResultSet rs = st.executeQuery(sql); ResultSetMetaData metadata = rs.getMetaData(); for (int i = 0; i < metadata.getColumnCount(); i++) { System.out.print("\t"+ metadata.getColumnLabel(i + 1)); } System.out.println("\n----------------------------------"); while (rs.next()) { for (int i = 0; i < metadata.getColumnCount(); i++) { Object value = rs.getObject(i + 1); if (value == null) { System.out.print("\t "); } else { System.out.print("\t"+value.toString().trim()); } } System.out.println(""); } }
}
File: Main.java import java.util.Collection; import javax.persistence.EntityManager; import javax.persistence.EntityManagerFactory; import javax.persistence.Persistence; public class Main {
public static void main(String[] a) throws Exception { JPAUtil util = new JPAUtil(); EntityManagerFactory emf = Persistence.createEntityManagerFactory("ProfessorService"); EntityManager em = emf.createEntityManager(); ProfessorService service = new ProfessorService(em); em.getTransaction().begin(); Professor emp = service.createProfessor("empName", 100); ParkingSpace pSpace = service.createParkingSpace(1, "location"); Professor emp1 = service.setProfessorParkingSpace(emp.getId(), pSpace.getId()); Collection<Professor> emps = service.findAllProfessors(); if (emps.isEmpty()) { System.out.println("No Professors found "); } else { System.out.println("Found Professors: "); for (Professor emp2 : emps) { System.out.println(emp2); } } Collection<ParkingSpace> pSpaces = service.findAllParkingSpaces(); if (pSpaces.isEmpty()) { System.out.println("No ParkingSpaces found "); } else { System.out.println("Found ParkingSpaces:"); for (ParkingSpace pSpace1 : pSpaces) { System.out.println(pSpace1); } } util.checkData("select * from Professor"); util.checkData("select * from ParkingSpace"); em.getTransaction().rumit(); em.close(); emf.close(); }
}
File: persistence.xml
<persistence xmlns="http://java.sun.ru/xml/ns/persistence"
xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xsi:schemaLocation="http://java.sun.ru/xml/ns/persistence http://java.sun.ru/xml/ns/persistence/persistence" version="1.0"> <persistence-unit name="JPAService" transaction-type="RESOURCE_LOCAL"> <properties> <property name="hibernate.dialect" value="org.hibernate.dialect.HSQLDialect"/> <property name="hibernate.hbm2ddl.auto" value="update"/> <property name="hibernate.connection.driver_class" value="org.hsqldb.jdbcDriver"/> <property name="hibernate.connection.username" value="sa"/> <property name="hibernate.connection.password" value=""/> <property name="hibernate.connection.url" value="jdbc:hsqldb:data/tutorial"/> </properties> </persistence-unit>
</persistence>
</source>
Retrieve One To One Mapped Entity
<source lang="java">
File: Address.java import javax.persistence.Entity; import javax.persistence.Id; @Entity public class Address {
@Id private int id; private String street; private String city; private String state; private String zip; public int getId() { return id; } public void setId(int id) { this.id = id; } public String getStreet() { return street; } public void setStreet(String address) { this.street = address; } public String getCity() { return city; } public void setCity(String city) { this.city = city; } public String getState() { return state; } public void setState(String state) { this.state = state; } public String getZip() { return zip; } public void setZip(String zip) { this.zip = zip; } public String toString() { return "Address id: " + getId() + ", street: " + getStreet() + ", city: " + getCity() + ", state: " + getState() + ", zip: " + getZip(); }
}
File: Student.java import javax.persistence.Entity; import javax.persistence.Id; import javax.persistence.OneToOne; @Entity public class Student {
@Id private int id; private String name; @OneToOne private Address address; 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 Address getAddress() { return address; } public void setAddress(Address address) { this.address = address; } public String toString() { return "\n\nID:" + id + "\nName:" + name + "\n\n"; }
}
File: Main.java import java.sql.Timestamp; import java.util.List; import java.util.UUID; import javax.persistence.EntityManager; import javax.persistence.EntityManagerFactory; import javax.persistence.Persistence; import javax.persistence.Query; public class Main {
static EntityManagerFactory emf = Persistence.createEntityManagerFactory("JPAService"); static EntityManager em = emf.createEntityManager(); public static void main(String[] a) throws Exception { em.getTransaction().begin(); Student student = new Student(); student.setName("Joe"); Address address = new Address(); em.persist(address); student.setAddress(address); em.persist(student); em.flush(); em.getTransaction().rumit(); Query query = em.createQuery("SELECT e FROM Student e"); List<Student> list = (List<Student>) query.getResultList(); System.out.println(list.get(0).getAddress()); em.close(); emf.close(); Helper.checkData(); }
}
File: Helper.java import java.sql.Connection; import java.sql.DriverManager; import java.sql.ResultSet; import java.sql.ResultSetMetaData; import java.sql.Statement; public class Helper {
public static void checkData() throws Exception { Class.forName("org.hsqldb.jdbcDriver"); Connection conn = DriverManager.getConnection("jdbc:hsqldb:data/tutorial", "sa", ""); Statement st = conn.createStatement(); ResultSet mrs = conn.getMetaData().getTables(null, null, null, new String[] { "TABLE" }); while (mrs.next()) { String tableName = mrs.getString(3); System.out.println("\n\n\n\nTable Name: "+ tableName); ResultSet rs = st.executeQuery("select * from " + tableName); ResultSetMetaData metadata = rs.getMetaData(); while (rs.next()) { System.out.println(" Row:"); for (int i = 0; i < metadata.getColumnCount(); i++) { System.out.println(" Column Name: "+ metadata.getColumnLabel(i + 1)+ ", "); System.out.println(" Column Type: "+ metadata.getColumnTypeName(i + 1)+ ": "); Object value = rs.getObject(i + 1); System.out.println(" Column Value: "+value+"\n"); } } } }
}
File: persistence.xml
<persistence xmlns="http://java.sun.ru/xml/ns/persistence"
xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xsi:schemaLocation="http://java.sun.ru/xml/ns/persistence http://java.sun.ru/xml/ns/persistence/persistence" version="1.0"> <persistence-unit name="JPAService" transaction-type="RESOURCE_LOCAL"> <properties> <property name="hibernate.dialect" value="org.hibernate.dialect.HSQLDialect"/> <property name="hibernate.hbm2ddl.auto" value="update"/> <property name="hibernate.connection.driver_class" value="org.hsqldb.jdbcDriver"/> <property name="hibernate.connection.username" value="sa"/> <property name="hibernate.connection.password" value=""/> <property name="hibernate.connection.url" value="jdbc:hsqldb:data/tutorial"/> </properties> </persistence-unit>
</persistence>
</source>