Source Code : One To One Unidirectional Mapping

Java Is Open Source Programming Language You Can Download From Java and Java Libraries From http://www.oracle.com. Click Here to download
We provide this code related to title for you to solve your developing problem easily. Libraries which is import in this program you can download from http://www.oracle.com. Click Here or search from google with Libraries Name you get jar file related it

One To One Unidirectional Mapping

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("	"+ metadata.getColumnLabel(i + 1)); 
    }
    System.out.println("
----------------------------------");

    while (rs.next()) {
      for (int i = 0; i < metadata.getColumnCount(); i++) {
        Object value = rs.getObject(i + 1);
        if (value == null) {
          System.out.print("	       ");
        } else {
          System.out.print("	"+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().commit();
    em.close();
    emf.close();
  }
}




File: persistence.xml

<persistence xmlns="http://java.sun.com/xml/ns/persistence"
             xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
             xsi:schemaLocation="http://java.sun.com/xml/ns/persistence http://java.sun.com/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>

           
       

Thank with us