How to initialize persistence.xml at the beginning of the program?

Question

I’m making a insert within a Postgresql database, however, as I have to test what connection to the database I will make, I end up having to configure the access based on each environment.

The problem is that I did it in a not very good way, since for each insertion I set up the bank again.

How can I load this setting only once, not at each insertion? I can’t leave the password hardcoded in the code as well.

What I’m currently doing:

import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.stereotype.Service;

import javax.persistence.*;
import java.util.Date;
import java.util.HashMap;
import java.util.Map;

@Service
public class ConteudoService extends AbstractService {
@Autowired
private ConteudoRepository conteudoRepository;

public EntityTransaction insertInDb(String something, String somethingElse) {

    Map<String, String> env = System.getenv();
    Map<String, Object> configOverrides = new HashMap<>();

    // Trocando as configurações do persistance.xml
    for(Map.Entry<String, String> entry: env.entrySet()) {
        if (entry.getKey().contains("DATABASE_URL")) {
            configOverrides.put("javax.persistence.jdbc.url", env.get(entry.getValue()));
        } else if (entry.getKey().contains("DATABASE_USER")) {
            configOverrides.put("javax.persistence.jdbc.user", env.get(entry.getValue()));
        } else if (entry.getKey().contains("DATABASE_PASSWORD")) {
            configOverrides.put("javax.persistence.jdbc.password", env.get(entry.getValue()));
        }
    }

    // Cria um factory dando override nas variáveis.
    EntityManagerFactory factory = Persistence.createEntityManagerFactory("default", configOverrides);
    EntityManager conteudoManager = factory.createEntityManager();

    Query query = conteudoManager.createNativeQuery("INSERT INTO something(" +
            "SOMETHING," +
            "SOMETHING_ELSE)" +
            " VALUES (" +
            ":something," +
            ":somethingElse)");

    conteudoManager.getTransaction().begin();

    query.setParameter("something", something);
    query.setParameter("somethingElse", somethingElse);
    query.executeUpdate();
    return conteudoManager.getTransaction();

}

public Conteudo getContent() {
    return conteudoRepository.getContent();
}

My persistence.xml:

<?xml version="1.0" encoding="UTF-8"?>
<persistence version="2.0" xmlns="http://java.sun.com/xml/ns/persistence"
             xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
             xsi:schemaLocation="http://java.sun.com/xml/ns/persistence
             http://java.sun.com/xml/ns/persistence/persistence_2_0.xsd">
    <persistence-unit name="default" transaction-type="RESOURCE_LOCAL">
        <provider>org.hibernate.ejb.HibernatePersistence</provider>
        <properties>
            <property name="hibernate.dialect" value="org.hibernate.dialect.PostgreSQLDialect" />
            <property name="javax.persistence.jdbc.url" value="url" />
            <property name="javax.persistence.jdbc.driver" value="org.postgresql.Driver" />
            <property name="javax.persistence.jdbc.password" value="password" />
            <property name="javax.persistence.jdbc.user" value="login" />
            <property name="hibernate.hbm2ddl.auto" value="update" />
            <property name="hibernate.show_sql" value="true"/>
            <property name="hibernate.format_sql" value="true"/>
        </properties>
    </persistence-unit>
</persistence>