Do I need to include classes mapped in persistence.xml? Java-Eclipse-Maven-Hibernate-H2database

Question

I’m trying to set up a Maven project in Eclipse with Hibernate and H2 Database. So I’m trying to understand the persistence.xml settings, which I had to create.

One question is: do I need to include the classes I’m going to map in this persistence.xml? I took an example from the internet that has:

<persistence 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"
    version="2.0">

 <persistence-unit name="tarefas">

   <!-- provedor/implementacao do JPA -->
   <provider>org.hibernate.jpa.HibernatePersistenceProvider</provider>

   <!-- entidade mapeada -->
   <class>br.com.caelum.tarefas.modelo.Tarefa</class>

   <properties>
    <!-- dados da conexao -->
     <property name="javax.persistence.jdbc.driver" 
             value="com.mysql.jdbc.Driver" />
    <property name="javax.persistence.jdbc.url" 
            value="jdbc:mysql://localhost/fj21" />
    <property name="javax.persistence.jdbc.user" 
            value="root" />
    <property name="javax.persistence.jdbc.password" 
            value="<SENHA DO BANCO AQUI>" />

     <!--  propriedades do hibernate -->
     <property name="hibernate.dialect" 
            value="org.hibernate.dialect.MySQL5InnoDBDialect" />
    <property name="hibernate.show_sql" value="true" />
    <property name="hibernate.format_sql" value="true" />

    <!--  atualiza o banco, gera as tabelas se for preciso -->
    <property name="hibernate.hbm2ddl.auto" value="update" />

   </properties>
 </persistence-unit>
</persistence>

It has an attribute/tag "class" that indicates the Java class to be mapped. I have to do this with all classes in my project?:

2- Another question is: if the above answer is yes, how does it work to indicate the relative path of the class relative to the location of my persistence.xml?

For example: see where . class and persistence.xmlareare in my project. How I point out the location of . class in persistence attributes?

Answer 1

You can map entities in two ways:

1 with the tag class, as you mentioned:

<class>caminho.inteiro.do.pacote.NomeDaEntidade</class>

2 with the annotation @Entity:

@Entity public class NomeDaEntidade { ... }

Answering the second question, how to inform the FQN - Full Qualified Name for the tag class, Hibernate knows exactly where the class is.