JPA read data from database example
In this section, you will learn how to retrieve data
from database using JPA. Create a "JPARead.java" file and follows the
following steps to reading data from database.
- Again, you create a "JPARead.java" file
- Put the following text in this file.
- Read code (JPARead.java):
/**
*
*/
package roseindia;
import java.util.Iterator;
import java.util.List;
import javax.persistence.EntityManager;
import javax.persistence.EntityManagerFactory;
import javax.persistence.Persistence;
import javax.persistence.Query;
/**
* @author Administrator
*
*/
public class JPARead {
/**
* @param args
*/
public static void main(String[] args) {
// TODO Auto-generated method stub
EntityManagerFactory emf =
Persistence.createEntityManagerFactory("jpa");
EntityManager em = emf.createEntityManager();
try{
em.getTransaction().begin();
//Select all the record from student table
Query query = em.createQuery("SELECT st FROM Student st");
List lst = query.getResultList();
Iterator it = lst.iterator();
while (it.hasNext()){
Student student = (Student) it.next();
System.out.print("Id:"+student.getId());
System.out.print(" Name:"+student.getSname());
System.out.println(" Course:"+student.getScourse());
}
em.getTransaction().commit();
}
catch(Exception e){
System.out.println(e.getMessage());
}
finally{
em.close();
}
}
} |
4.Run and get the output in Console window.
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