File: Main.java
import java.util.Date; import java.util.List; import javax.persistence.EntityManager; import javax.persistence.EntityManagerFactory; import javax.persistence.FlushModeType; 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(); Query query = em.createQuery("SELECT d FROM Student e JOIN e.department d"); System.out.println(query.getResultList()); em.getTransaction().commit(); em.close(); emf.close(); Helper.checkData(); } }
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: Department.java
import java.util.HashSet; import java.util.Set; import javax.persistence.Entity; import javax.persistence.Id; import javax.persistence.OneToMany; @Entity public class Department { @Id private int id; private String name; @OneToMany(mappedBy="department") private Set<Student> students = new HashSet<Student>(); public int getId() { return id; } public void setId(int deptNo) { this.id = deptNo; } public String getName() { return name; } public void setName(String deptName) { this.name = deptName; } public Set<Student> getStudents() { return students; } public String toString() { return "Department no: " + getId() + ", name: " + getName(); } }
File: Phone.java
import javax.persistence.Entity; import javax.persistence.Id; import javax.persistence.OneToOne; @Entity public class Phone { @Id private long id; private String number; private String type; @OneToOne Student student; public long getId() { return id; } public void setId(long id) { this.id = id; } public String getNumber() { return number; } public void setNumber(String phoneNo) { this.number = phoneNo; } public String getType() { return type; } public void setType(String phoneType) { this.type = phoneType; } public Student getStudent() { return student; } public void setStudent(Student student) { this.student = student; } public String toString() { return "Phone id: " + getId() + ", no: " + getNumber() + ", type: " + getType(); } }
File: Project.java
import java.util.ArrayList; import java.util.Collection; import javax.persistence.Entity; import javax.persistence.Id; import javax.persistence.Inheritance; import javax.persistence.ManyToMany; @Entity public class Project { @Id protected int id; protected String name; @ManyToMany protected Collection<Student> students = new ArrayList<Student>(); public int getId() { return id; } public void setId(int projectNo) { this.id = projectNo; } public String getName() { return name; } public void setName(String projectName) { this.name = projectName; } public Collection<Student> getStudents() { return students; } public void addStudent(Student student) { if (!getStudents().contains(student)) { getStudents().add(student); } if (!student.getProjects().contains(this)) { student.getProjects().add(this); } } public String toString() { return getClass().getName().substring(getClass().getName().lastIndexOf('.')+1) + " no: " + getId() + ", name: " + getName(); } }
File: Student.java
import java.util.ArrayList; import java.util.Collection; import java.util.Date; import javax.persistence.Entity; import javax.persistence.Id; import javax.persistence.ManyToMany; import javax.persistence.ManyToOne; import javax.persistence.OneToMany; import javax.persistence.OneToOne; import javax.persistence.Temporal; import javax.persistence.TemporalType; @Entity public class Student { @Id private int id; private String name; private long salary; @Temporal(TemporalType.DATE) private Date startDate; @OneToOne private Address address; @OneToMany(mappedBy="student") private Collection<Phone> phones = new ArrayList<Phone>(); @ManyToOne private Department department; @ManyToOne private Student manager; @OneToMany(mappedBy="manager") private Collection<Student> directs = new ArrayList<Student>(); @ManyToMany(mappedBy="students") private Collection<Project> projects = new ArrayList<Project>(); public int getId() { return id; } public void setId(int empNo) { this.id = empNo; } 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 Date getStartDate() { return startDate; } public void setStartDate(Date startDate) { this.startDate = startDate; } public Collection<Phone> getPhones() { return phones; } public void addPhone(Phone phone) { if (!getPhones().contains(phone)) { getPhones().add(phone); if (phone.getStudent() != null) { phone.getStudent().getPhones().remove(phone); } phone.setStudent(this); } } public Department getDepartment() { return department; } public void setDepartment(Department department) { if (this.department != null) { this.department.getStudents().remove(this); } this.department = department; this.department.getStudents().add(this); } public Collection<Student> getDirects() { return directs; } public void addDirect(Student student) { if (!getDirects().contains(student)) { getDirects().add(student); if (student.getManager() != null) { student.getManager().getDirects().remove(student); } student.setManager(this); } } public Student getManager() { return manager; } public void setManager(Student manager) { this.manager = manager; } public Collection<Project> getProjects() { return projects; } public void addProject(Project project) { if (!getProjects().contains(project)) { getProjects().add(project); } if (!project.getStudents().contains(this)) { project.getStudents().add(this); } } public Address getAddress() { return address; } public void setAddress(Address address) { this.address = address; } public String toString() { return "Student " + getId() + ": name: " + getName() + ", salary: " + getSalary() + ", phones: " + getPhones() + ", managerNo: " + ((getManager() == null) ? null : getManager().getId()) + ", deptNo: " + ((getDepartment() == null) ? null : getDepartment().getId()); } }
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.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>