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.