Hibernate: How specify custom sequence generator class name using annotations?
please refer the custom-id-generator-in-hibernate this may help you. In this example, I am creating the sequence number by taking MAX number from primary key table called pk_table.
Employee Class looks as follows.
@Entity
@Table(name="EMPLOYEE")
public class Employee {
@Id
@GenericGenerator(name = "sequence_emp_id", strategy = "com.supportmycode.model.EmployeeIdGenerator")
@GeneratedValue(generator = "sequence_emp_id")
@Column(name="employee_id")
private String employeeId;
@Column(name="firstname")
private String firstname;
@Column(name="lastname")
private String lastname;
@Column(name="birth_date")
private Date birthDate;
@Column(name="cell_phone")
private String cellphone;
//Getter and Setter methods.
}
EmployeeIdGenerator class looks as follows
public class EmployeeIdGenerator implements IdentifierGenerator {
public Serializable generate(SessionImplementor session, Object object)
throws HibernateException {
String prefix = "EMP";
Connection connection = session.connection();
try {
PreparedStatement ps = connection
.prepareStatement("SELECT MAX(value) as value from hibernate_tutorial.pk_table");
ResultSet rs = ps.executeQuery();
if (rs.next()) {
int id = rs.getInt("value");
String code = prefix + new Integer(id).toString();
System.out.println("Generated Stock Code: " + code);
return code;
}
} catch (SQLException e) {
e.printStackTrace();
}
return null;
}
}
Here, we have Implemented the interface IdentifierGenerator
to override the function generate(SessionImplementor session, Object object)
. the statement SELECT MAX(value) as value from hibernate_tutorial.pk_table
will get the MAX number from the table pk_table. And then we prefix the MAX number with the string "EMP".
Output looks as follows:
EMPLOYEE
------------------------------------------------------------
employee_id | birth_date | cell_phone | firstname | lastname
------------------------------------------------------------
EMP1 | 2014-08-22 | 111 | Nina | Mayers
please find below set of code which i have used in project for the same.
@Id
@GeneratedValue(strategy = GenerationType.SEQUENCE, generator = "XyzIdGenerator")
@GenericGenerator(name = "XyzIdGenerator",
strategy = "com.mycompany.myapp.id.BigIntegerSequenceGenerator",
parameters = {
@Parameter(name = "sequence", value = "xyz_id_sequence")
})
public BigInteger getId()
{
return id;
}
package com.mycompany.myapp.id;
import org.hibernate.id.SequenceGenerator;
...
public class BigIntegerSequenceGenerator
extends SequenceGenerator
{
@Override
public Serializable generate(SessionImplementor session, Object obj)
{
...
}
}