Как создать подключение к БД через persistence.xml?

<persistence>
  <persistence-unit name="MyPU">
    <properties>
      <property name="javax.persistence.jdbc.driver" value="org.postgresql.Driver" />
      <property name="javax.persistence.jdbc.url" value="jdbc:postgresql://localhost:5432/somedb" />
      <property name="javax.persistence.jdbc.user" value="user" />
      <property name="javax.persistence.jdbc.password" value="password" />

      <property name="hibernate.dialect" value="org.hibernate.dialect.PostgreSQL96Dialect"/>
      <property name="hibernate.hbm2ddl.auto" value="update" />
    </properties>
  </persistence-unit>
</persistence>