Java tutorial
File:Address.java
import javax.persistence.Column;
import javax.persistence.Embeddable;
@Embeddable
public class Address {
private String street;
private String city;
private String state;
@Column(name="ZIP_CODE")
private String zip;
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 street: " + getStreet() +
", city: " + getCity() +
", state: " + getState() +
", zip: " + getZip();
}
}
File:Company.java
import javax.persistence.Embedded;
import javax.persistence.Entity;
import javax.persistence.Id;
@Entity
public class Company {
@Id private String name;
@Embedded
private Address address;
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 "Company name: " + getName() +
" at " + getAddress();
}
}
File:Professor.java
import javax.persistence.Embedded;
import javax.persistence.Entity;
import javax.persistence.Id;
@Entity
public class Professor {
@Id private int id;
private String name;
private long salary;
@Embedded 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() +
" with " + getAddress();
}
}
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 createProfessorAndAddress(int id, String name, long salary, String street,
String city, String state, String zip) {
Professor emp = new Professor();
emp.setId(id);
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);
return emp;
}
public Company createCompanyAndAddress(String name,
String street, String city, String state, String zip) {
Company c = new Company();
c.setName(name);
Address addr = new Address();
addr.setStreet(street);
addr.setCity(city);
addr.setState(state);
addr.setZip(zip);
c.setAddress(addr);
em.persist(c);
return c;
}
public Collection<Professor> findAllProfessors() {
Query query = em.createQuery("SELECT e FROM Professor e");
return (Collection<Professor>) query.getResultList();
}
public Collection<Company> findAllCompanies() {
Query query = em.createQuery("SELECT e FROM Company e");
return (Collection<Company>) 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();
service.createProfessorAndAddress(1, "name", 100, "street", "city", "state", "zip");
service.createCompanyAndAddress("Name", "Street", "City", "State", "Zip");
System.out.println("Professors and Addresses:");
for (Professor emp : service.findAllProfessors()) {
System.out.println(emp);
}
for (Company c : service.findAllCompanies()) {
System.out.println(c);
}
util.checkData("select * from Professor");
util.checkData("select * from Company");
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>