Question

Is it possible to use PersistenceContext as annotation for JPA in a normal JAVA class? If not, can you please tell me how to use the PersistenceContext without any annotation?

Answer 1

Yes, you can use @PersistenceContext in any Java class. However, you must specify annotation-config in your Spring configuration, as in the following example:

<?xml version="1.0" encoding="UTF-8"?>
<beans xmlns="http://www.springframework.org/schema/beans" 
    xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
    xmlns:context="http://www.springframework.org/schema/context"
    xsi:schemaLocation="
        http://www.springframework.org/schema/beans http://www.springframework.org/schema/beans/spring-beans-3.0.xsd
        http://www.springframework.org/schema/context http://www.springframework.org/schema/context/spring-context-3.0.xsd">

    <context:annotation-config/>
</beans>

Once you have that specified, you can use @PersistenceContext as follows:

package com.sample.dao.impl

import java.util.List;

import javax.persistence.EntityManager;
import javax.persistence.Query;

import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.beans.factory.annotation.Qualifier;

public class CustomerDaoImpl {

    @PersistenceContext
    private EntityManager em;

    public Customer getCustomerByName(String customerName) {
        Query query = em.createQuery("SELECT c FROM Customer c WHERE c.name = ?1");
        query.setParameter(1, customerName);
        List<Customer> results = query.getResultList();
        if (results.size() > 0) {
            return results.get(0);
        }
        return null;
    }
}