Hibernate Component Mapping Annotation

Component dependent object:

A component is a contained object that is persisted as a value type and not an entity reference. The term “component” refers to the object-oriented notion of composition and not to architecture-level components.

Historically Hibernate called these components. JPA calls them embeddables. Either way the concept is the same: a composition of values. For example we might have a Name class that is a composition of first-name and last-name, or an Address class that is a composition of street, city, postal code, etc.

The @Embeddable annotation is used to specify embeddable types. Like basic types, embeddable types do not have any identity, being managed by their owning entity.

The @Embedded annotation is used to specify that a given entity attribute represents an embeddable type.

Component Annotation @Embedded mapping

POJO CLASSES

Student.java

package com.vaannila.student;
import javax.persistence.Column;
import javax.persistence.Embedded;
import javax.persistence.Entity;
import javax.persistence.GeneratedValue;
import javax.persistence.Id;
import javax.persistence.Table;
@Entity
@Table(name = "student")
public class Student {
  private long studentId;
  private String studentName;
  private Address studentAddress;
  public Student() {
  }
  public Student(String studentName, Address studentAddress) {
    this.studentName = studentName;
    this.studentAddress = studentAddress;
  }
  @Id
  @GeneratedValue
  @Column(name = "STUDENT_ID")
  public long getStudentId() {
    return this.studentId;
  }
  public void setStudentId(long studentId) {
    this.studentId = studentId;
  }
  @Column(name = "STUDENT_NAME", nullable = false, length = 100)
  public String getStudentName() {
    return this.studentName;
  }
  public void setStudentName(String studentName) {
    this.studentName = studentName;
  }
  @Embedded
  public Address getStudentAddress() {
    return this.studentAddress;
  }
  public void setStudentAddress(Address studentAddress) {
    this.studentAddress = studentAddress;
  }
}

Address.java

package com.vaannila.student;
import javax.persistence.Column;
import javax.persistence.Embeddable;
@Embeddable
public class Address {
  private String street;
  private String city;
  private String state;
  private String zipcode;
  public Address() {
  }
  public Address(String street, String city, String state, String zipcode) {
    this.street = street;
    this.city = city;
    this.state = state;
    this.zipcode = zipcode;
  }
  @Column(name = "ADDRESS_STREET", nullable = false, length = 250)
  public String getStreet() {
    return this.street;
  }
  public void setStreet(String street) {
    this.street = street;
  }
  @Column(name = "ADDRESS_CITY", nullable = false, length = 50)
  public String getCity() {
    return this.city;
  }
  public void setCity(String city) {
    this.city = city;
  }
  @Column(name = "ADDRESS_STATE", nullable = false, length = 50)
  public String getState() {
    return this.state;
  }
  public void setState(String state) {
    this.state = state;
  }
  @Column(name = "ADDRESS_ZIPCODE", nullable = false, length = 10)
  public String getZipcode() {
    return this.zipcode;
  }
  public void setZipcode(String zipcode) {
    this.zipcode = zipcode;
  }
}

Saving Objects to Component mapping

public void insertStudent(Student student) {
    Session s = getSession();
    Transaction transaction = s.beginTransaction();
    s.save(student);
    transaction.commit();
  }

Retrieving Objects from Component Mapping (session.get())

public Student getStudent(long id) {
    Student sd = null;
    Session s = getSession();
    sd = (Student) s.get(Student.class, id);
    return sd;
}

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Hibernate Component Mapping Annotation