JPA Locate Function

In this section, you will learn about the JPA locate() function. This method returns the index of search string in specified string. String positions are 1-based.

JPA Locate Function

JPA Locate Function

     

In this section, you will learn about the JPA locate() function. This method returns the index of search string in specified string. String positions are 1-based. If string is not found then it returns "0".

JPA locate Function:

Query query=
em.createQuery("SELECT st FROM Student st WHERE LOCATE('i',st.sname)=2");

This query retrieves the sname from student table which have "i" position is equal to "2".

For JPA Locate application, you need the following artifacts:

  1. Database Table: student
  2. Model Class: Student.java
  3. Main Class: JPALocateFunction.java

Database Table: student

CREATE TABLE `student` ( 
`id` int(11) NOT NULL auto_increment, 
`sname` varchar(100) NOT NULL, 
`sroll` int(11) NOT NULL, 
`scourse` varchar(10) NOT NULL, 
PRIMARY KEY (`id`) 

Model Class: Student.java

/**

*/
package roseindia;

import javax.persistence.Column;
import javax.persistence.Entity;
import javax.persistence.GeneratedValue;
import javax.persistence.Id;
import javax.persistence.NamedQueries;
import javax.persistence.NamedQuery;
import javax.persistence.Table;

/**
* @author Administrator
*
*/
@Entity
@Table(name="student")

public class Student {

@Id
@GeneratedValue
private int id;

/**
* @return the id
*/
public int getId() {
return id;
}

/**
* @param id the id to set
*/
public void setId(int id) {
this.id = id;
}

@Column(name="sname", length=100,nullable=false)
private String sname;

/**
* @return the sname
*/
public String getSname() {
return sname;
}

/**
* @param sname the sname to set
*/
public void setSname(String sname) {
this.sname = sname;
}

@Column(name="sroll",nullable=false)
private int sroll;

/**
* @return the sroll
*/
public int getSroll() {
return sroll;
}

/**
* @param sroll the sroll to set
*/
public void setSroll(int sroll) {
this.sroll = sroll;
}

@Column(name="scourse",length=10,nullable=false)
private String scourse;

/**
* @return the scourse
*/
public String getScourse() {
return scourse;
}

/**
* @param scourse the scourse to set
*/
public void setScourse(String scourse) {
this.scourse = scourse;
}

}

Main Class: JPALocateFunction.java

/**
* 
*/
package roseindia;

import java.util.Iterator;
import java.util.List;

import javax.persistence.EntityManager;
import javax.persistence.EntityManagerFactory;
import javax.persistence.EntityTransaction;
import javax.persistence.Persistence;
import javax.persistence.Query;

/**
* @author Administrator
*
*/
public class JPALocateFunction {

/**
* @param args
*/
public static void main(String[] args) {
// TODO Auto-generated method stub

EntityManagerFactory emf=Persistence.createEntityManagerFactory("jpa");
EntityManager em=emf.createEntityManager();
try{
EntityTransaction entr=em.getTransaction();
entr.begin();
Query query=em.createQuery("SELECT st FROM Student st WHERE LOCATE('i',st.sname)=2");
List stuList=query.getResultList();
Iterator stuIterator=stuList.iterator();
while(stuIterator.hasNext()){
Student st=(Student)stuIterator.next();
System.out.print("sname:"+st.getSname());
System.out.println();
}
entr.commit();
}
finally{
em.close();
}
}
}

Output:

log4j:WARN No appenders could be found for logger
(org.hibernate.cfg.annotations.Version).

log4j:WARN Please initialize the log4j system properly.

Hibernate: select student0_.id as id0_, student0_.scourse as
scourse0_, student0_.sname as sname0_, student0_.sroll as
sroll0_ from student student0_ where locate('i', student0_.sname)=2

sname:VINOD

sname:Vinit

 

Student table records: