hibernate criteria Distinct Result Example
In This example search the result according to Criteria Restriction and like condition. The DISTINCT_ROOT_ENTITY field is ensures that each row of results is a distinct instance of the root entity.
In This example search the result according to Criteria Restriction and like condition. The DISTINCT_ROOT_ENTITY field is ensures that each row of results is a distinct instance of the root entity.hibernate criteria Distinct Result Example
In this Example, We will discuss about hibernate criteria query, In this example we create a criteria instance and implement the factory methods for obtaining certain built-in Criterion types method. In This example search the result according to Criteria Restriction and like condition. The DISTINCT_ROOT_ENTITY field is ensures that each row of results is a distinct instance of the root entity.
Here is the simple Example code files.
CriteriaDistincExample.java
package roseindia;
import java.util.Iterator;
import java.util.List;
import org.hibernate.Criteria;
import org.hibernate.HibernateException;
import org.hibernate.Session;
import org.hibernate.criterion.Restrictions;
import roseindia.bean.User;
import roseindia.util.HibernateUtil;
public class CriteriaDistincExample {
public static void main(String[] args) {
Session session = HibernateUtil.getSessionFactory().openSession();
User user = null;
try {
// Creating a Criteria instance
Criteria crit = session.createCriteria(User.class);
crit.add(Restrictions.like("empName", "Gyan%"));
crit.add(Restrictions.gt("expInMonth", 50));
crit.setResultTransformer(Criteria.DISTINCT_ROOT_ENTITY);
List list = crit.list();
Iterator itr = list.iterator();
while (itr.hasNext()) {
user = (User) itr.next();
System.out.println("EmpId: " + user.getEmpId());
System.out.printf("\t");
System.out.println("EmpName: " + user.getEmpName());
System.out.printf("\t");
System.out.println("EmpAddr: " + user.getEmpAddr());
System.out.printf("\t");
System.out.println("ExpInMonth: " + user.getExpInMonth());
}
} catch (HibernateException e) {
e.printStackTrace();
} finally {
session.close();
}
}
}
The bean class is as follows.
package roseindia.bean;
import java.util.Date;
public class User implements java.io.Serializable {
private static final long serialVersionUID = 1L;
private long Id = 0;
private int empId = 0;
private String empName = null;
private String empAddr = null;
private String empPhone = null;
private String empEmail = null;
private Date empDOB = null;
private int expInMonth = 0;
private double empSalary = 0.0;
public User() {
}
public User(int empId ,String empName, String empAddr, String empPhone,
String empEmail, Date empDOB, int expInMonth, double empSalary) {
this.empId=empId;
this.empName = empName;
this.empAddr = empAddr;
this.empPhone = empPhone;
this.empEmail = empEmail;
this.empDOB = empDOB;
this.expInMonth = expInMonth;
this.empSalary = empSalary;
}
public long getId() {
return Id;
}
public void setId(long id) {
Id = id;
}
public int getEmpId() {
return empId;
}
public void setEmpId(int empId) {
this.empId = empId;
}
public String getEmpName() {
return empName;
}
public void setEmpName(String empName) {
this.empName = empName;
}
public String getEmpAddr() {
return empAddr;
}
public void setEmpAddr(String empAddr) {
this.empAddr = empAddr;
}
public String getEmpPhone() {
return empPhone;
}
public void setEmpPhone(String empPhone) {
this.empPhone = empPhone;
}
public String getEmpEmail() {
return empEmail;
}
public void setEmpEmail(String empEmail) {
this.empEmail = empEmail;
}
public Date getEmpDOB() {
return empDOB;
}
public void setEmpDOB(Date empDOB) {
this.empDOB = empDOB;
}
public int getExpInMonth() {
return expInMonth;
}
public void setExpInMonth(int expInMonth) {
this.expInMonth = expInMonth;
}
public double getEmpSalary() {
return empSalary;
}
public void setEmpSalary(double empSalary) {
this.empSalary = empSalary;
}
@Override
public String toString() {
return "User [empAddr=" + empAddr + ", empDOB=" + empDOB
+ ", empEmail=" + empEmail + ", empId=" + empId + ", empName="
+ empName + ", empPhone=" + empPhone + ", empSalary="
+ empSalary + ", expInMonth=" + expInMonth + "]";
}
}
We use the following code to insert the values in the database table using mapping file.
DataInsert.java
package roseindia;
import java.util.Date;
import org.hibernate.HibernateException;
import org.hibernate.Session;
import org.hibernate.Transaction;
import roseindia.bean.User;
import roseindia.util.HibernateUtil;
public class DataInsert {
public static void main(String[] args) {
Session session = HibernateUtil.getSessionFactory().openSession();
Transaction transaction = null;
User user = null;
try {
transaction = session.beginTransaction();
for (int i = 0; i < 10; i++) {
user = new User( 1 * i,"Gyan " + i, "NEW DELHI" + i,
"68784654654" + i, "[email protected]" + i, new Date(),
12 * i, 15398.00 * i);
session.save(user);
}
transaction.commit();
} catch (HibernateException e) {
transaction.rollback();
e.printStackTrace();
} finally {
session.close();
}
}
}
The database table mapping is in the file User.hbm.xml and hibernate configuration file is hibernate.cfg.xml.
hibernate.cfg.xml
<?xml version='1.0' encoding='utf-8'?> <!DOCTYPE hibernate-configuration PUBLIC "-//Hibernate/Hibernate Configuration DTD 3.0//EN" "http://hibernate.sourceforge.net/hibernate-configuration-3.0.dtd"> <hibernate-configuration> <session-factory> <!-- Database connection settings --> <property name="connection.driver_class">com.mysql.jdbc.Driver</property> <property name="connection.url">jdbc:mysql://localhost:3306/test</property> <property name="connection.username">root</property> <property name="connection.password"></property> <!-- JDBC connection pool (use the built-in) --> <property name="connection.pool_size">10</property> <!-- SQL dialect --> <property name="dialect">org.hibernate.dialect.MySQLDialect</property> <!-- Enable Hibernate's automatic session context management --> <property name="current_session_context_class">thread</property> <!-- Disable the second-level cache --> <property name="cache.provider_class">org.hibernate.cache.NoCacheProvider</property> <!-- Echo all executed SQL to stdout --> <property name="show_sql">true</property> <!-- Drop and re-create the database schema on startup --> <property name="hbm2ddl.auto">update</property> <mapping resource="roseindia/bean/User.hbm.xml" /> </session-factory> </hibernate-configuration>
The User.hbm.xml file is as follows-
<?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="roseindia.bean.User" table="EMPLOYEE"> <id name="Id" type="long" column="ID"> <generator class="native" /> </id> <property name="empId" type="int" length="100" not-null="false" column="EMP_ID" /> <property name="empName" type="java.lang.String" length="100" not-null="false" column="EMP_NAME" /> <property name="empAddr" type="java.lang.String" length="100" not-null="false" column="EMP_ADDR" /> <property name="empPhone" type="java.lang.String" length="100" not-null="false" column="EMP_PHONE" /> <property name="empEmail" type="java.lang.String" length="100" not-null="false" column="EMP_EMAIL" /> <property name="empDOB" type="java.util.Date" not-null="false" column="EMP_DOB" /> <property name="expInMonth" type="int" not-null="false" column="EXP_IN_MONTH" /> <property name="empSalary" type="double" not-null="false" column="EMP_SALARY" /> </class> </hibernate-mapping>
The HibernateUtil.java is as follows, is used to get the SessionFactory object to open session.
package roseindia.util;
import org.hibernate.SessionFactory;
import org.hibernate.cfg.Configuration;
public class HibernateUtil {
private static final SessionFactory sessionFactory;
static {
try {
sessionFactory = new Configuration().configure()
.buildSessionFactory();
} catch (Throwable ex) {
System.err.println("Initial SessionFactory creation failed." + ex);
throw new ExceptionInInitializerError(ex);
}
}
public static SessionFactory getSessionFactory() {
return sessionFactory;
}
}
This example give the output the values from the table according to the criteria defined.
The structure of the database table is as follows:
The resultant query generated by hibernate is as follows which produces the output as follows
Hibernate: select this_.ID as ID0_0_, this_.EMP_ID as EMP2_0_0_, this_.EMP_NAME as EMP3_0_0_, this_.EMP_ADDR as EMP4_0_0_, this_.EMP_PHONE as EMP5_0_0_, this_.EMP_EMAIL as EMP6_0_0_, this_.EMP_DOB as EMP7_0_0_, this_.EXP_IN_MONTH as EXP8_0_0_, this_.EMP_SALARY as EMP9_0_0_ from EMPLOYEE this_ where this_.EMP_NAME like ? and this_.EXP_IN_MONTH>?
