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.
Component xml mapping
Student.hbm.xml
<?xml version="1.0"?>
<!DOCTYPE hibernate-mapping PUBLIC
"-//Hibernate/Hibernate Mapping DTD 3.0//EN"
"http://hibernate.sourceforge.net/hibernate-mapping-3.0.dtd">
<hibernate-mapping>
<class name="com.candidjava.hibernate.Student" table="Student_component">
<id name="studentId" type="long" column="STUDENT_ID">
<generator class="increment" />
</id>
<property name="studentName" type="string" not-null="true"
column="STUDENT_NAME" />
<component name="studentAddress" class="com.candidjava.hibernate.Address">
<property name="street" column="ADDRESS_STREET" type="string"
length="250" />
<property name="city" column="ADDRESS_CITY" type="string"
length="50" />
<property name="state" column="ADDRESS_STATE" type="string"
length="50" />
<property name="zipcode" column="ADDRESS_ZIPCODE" type="string"
length="10" />
</component>
</class>
</hibernate-mapping>
Pojo classes
Student.java
package com.candidjava.hibernate;
public class Student implements java.io.Serializable {
private static final long serialVersionUID = 1L;
private long studentId;
private String studentName;
private Address studentAddress;
public long getStudentId() {
return studentId;
}
public void setStudentId(long studentId) {
this.studentId = studentId;
}
public String getStudentName() {
return studentName;
}
public void setStudentName(String studentName) {
this.studentName = studentName;
}
public Address getStudentAddress() {
return studentAddress;
}
public void setStudentAddress(Address studentAddress) {
this.studentAddress = studentAddress;
}
}Address.java
package com.candidjava.hibernate;
public class Address implements java.io.Serializable {
private static final long serialVersionUID = 1L;
private long addressId;
private String street;
private String city;
private String state;
private String zipcode;
public long getAddressId() {
return addressId;
}
public void setAddressId(long addressId) {
this.addressId = addressId;
}
public String getStreet() {
return street;
}
public void setStreet(String street) {
this.street = street;
}
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 getZipcode() {
return zipcode;
}
public void setZipcode(String zipcode) {
this.zipcode = zipcode;
}
public Address() {
}
}
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;
}Download Example
