A library to work with Hibernate by fluent API. This library hasn't dependencies, except Hibernate libraries. It requires Java 1.6 and above. It can be used with Hibernate 5 and Hibernate 4.
<dependency>
<groupId>com.github.v-ladynev</groupId>
<artifactId>fluent-hibernate-core</artifactId>
<version>0.3.1</version>
</dependency>All versions in the Maven repository: fluent-hibernate-core
compile 'com.github.v-ladynev:fluent-hibernate-core:0.3.1'If you want to use the library with Hibernate 4, you can consider to exclude a transitive dependency to Hibernate 5. For example, using Gradle:
compile('com.github.v-ladynev:fluent-hibernate-core:0.3.1') {
exclude group: 'org.hibernate'
}fluent-hibrnate has features which can be used with plain Hibernate or Spring code without a library infrastructure.
The library can be used for a quick entities scanning. You will need just the library jar, without additional dependencies. Just download the library using Download section and use EntityScanner:
For Hibernate 4 and Hibernate 5
Configuration configuration = new Configuration();
EntityScanner.scanPackages("my.com.entities", "my.com.other.entities")
.addTo(configuration);
SessionFactory sessionFactory = configuration.buildSessionFactory();Using a new Hibernate 5 bootstrapping API
List<Class<?>> classes = EntityScanner
.scanPackages("my.com.entities", "my.com.other.entities").result();
MetadataSources metadataSources = new MetadataSources();
for (Class<?> annotatedClass : classes) {
metadataSources.addAnnotatedClass(annotatedClass);
}
SessionFactory sessionFactory = metadataSources.buildMetadata()
.buildSessionFactory();It generates table and column names with underscores, like ImprovedNamingStrategy from Hibernate 4 and Hibernate 3, and constraint names
(unique, foreign key) as well. Apart those, it has a lot of configurable interesting features
like: plural table names, table and column prefixes, embedded column prefixes via the custom @FluentName annotation, automatic name restriction (by removing the vowels) and others.
Just download the library using Download section and use Hibernate5NamingStrategy:
Configuration configuration = new Configuration();
configuration.setImplicitNamingStrategy(new Hibernate5NamingStrategy());
SessionFactory sessionFactory = configuration.configure().buildSessionFactory();Using strategy options for a tables prefix and a names restriction except the join table names
Configuration configuration = new Configuration();
configuration.setImplicitNamingStrategy(
new Hibernate5NamingStrategy(StrategyOptions.builder().tablePrefix("acps")
.restrictLength(50).restrictJoinTableNames(false).build()));
SessionFactory sessionFactory = configuration.configure().buildSessionFactory();Using Spring
<bean id="sessionFactory" class="org.springframework.orm.hibernate5.LocalSessionFactoryBean">
<property name="implicitNamingStrategy">
<bean class="com.github.fluent.hibernate.cfg.strategy.hibernate5.Hibernate5NamingStrategy">
<property name="options">
<bean class="com.github.fluent.hibernate.cfg.strategy.StrategyOptions">
<property name="tablePrefix" value="acps" />
<property name="maxLength" value="50" />
<property name="restrictJoinTableNames" value="false" />
</bean>
</property>
</bean>
</property>
</bean>It is imposible to use Hibernate 4 naming strategies, for an example org.hibernate.cfg.ImprovedNamingStrategy, with Hibernate 5 (HHH-10155). To continue using ImprovedNamingStrategy functionality with Hibernate 5
ImprovedNamingStrategyHibernate5 can be used. Apart an ImprovedNamingStrategy behaviour, ImprovedNamingStrategyHibernate5 provides generation of foreign key and unique constraint names like Hibernate 4 does (with some limitations, see below).
Just pass ImprovedNamingStrategyHibernate5 to the Hibernate 5 configuration. ImprovedNamingStrategyHibernate5 implements the ImplicitNamingStrategy interface, so you can place it everywhere ImplicitNamingStrategy can be placed.
For an example, using Configuration:
Configuration configuration = new Configuration();
configuration.setImplicitNamingStrategy(ImprovedNamingStrategyHibernate5.INSTANCE);
SessionFactory sessionFactory = configuration.configure().buildSessionFactory();ImprovedNamingStrategyHibernate5 can be used with JPA configuration as well.
Keep in mind, that ImprovedNamingStrategyHibernate5 has some limitations are described below. I think, that these
limitations can be encountered in rarely situations. If you have problems with these situations fill free to create an issue or make a pull request.
I used ImprovedNamingStrategyHibernate5Test to test the strategy. To check an ImprovedNamingStrategy behaviour with Hibernate 4 I used this unit test: ImprovedNamingStrategyTest.
Foreign key and unique constraint names are generated by Hibernate 5 are slightly different from ones are generated by Hibernate 4.
I implement a Hibernate 4 behaviour in ImprovedNamingStrategyHibernate5, but Hibernate 5 doesn't always use a naming strategy to generate unique constraint names. For an, example: a unique constraint for @OneToMany annotation using a join table and @Column(unique = true) don't use ImplicitNamingStrategy. You need to delete such unique constraint names yourself, before Hibernate 5 will update a schema.
Hibernate 5 doesn't use a naming strategy to generate such names, because of an issue. Hiibernate 5 generates DTYPE name for the discriminator column. Hibernate 4 uses ImprovedNamingStrategy#columnName() to convert DTYPE to dtype. You need to provide explicit names in such situation.
Hibernate 5 doesn't use a naming strategy to generate such names, because of an issue. Hibernate 5 generates booksOrdered_ORDER, opposite books_ordered_order is generated by Hibernate 4 ImprovedNamingStrategy. You need to provide explicit names in such situation.
Hibernate 5 doesn't use a naming strategy to generate such names, because of an issue. Hibernate 5 generates booksMap_KEY, opposite books_map_key is generated by Hibernate 4 ImprovedNamingStrategy. You need to provide explicit names in such situation.
There are some methods in the ImplicitNamingStrategy are not used by Hibernate 5 to generate names. And there are some methods for which I can't represent unit tests. All these methods throw UnsupportedOperationException. The list of methods below
Identifier determineTenantIdColumnName(ImplicitTenantIdColumnNameSource source);
Identifier determineIdentifierColumnName(ImplicitIdentifierColumnNameSource source);
Identifier determinePrimaryKeyJoinColumnName(ImplicitPrimaryKeyJoinColumnNameSource source);
Identifier determineAnyDiscriminatorColumnName(ImplicitAnyDiscriminatorColumnNameSource source);
Identifier determineAnyKeyColumnName(ImplicitAnyKeyColumnNameSource source);This adapter can be used to adapt Hibernate 4 naming strategies to Hibernate 5 ImplicitNamingStrategy. ImprovedNamingStrategy for Hibernate 5 is builded on top of it. So it has the same limitations.
You can use the adapter by this way:
Configuration configuration = new Configuration();
configuration.setImplicitNamingStrategy(new Hibernate4To5NamingStrategyAdapter(EJB3NamingStrategy.INSTANCE));
SessionFactory sessionFactory = configuration.configure().buildSessionFactory();It can be used with JPA configuration as well. Probably, you will need to extend Hibernate4To5NamingStrategyAdapter similar as ImprovedNamingStrategyHibernate5 extends it.
It is a custom transformer like Transformers.aliasToBean(SomeDto.class), but with the nested projections support.
Just download the library using Download section and use FluentHibernateResultTransformer.
Load User only with login and department.name fields
@Entity
@Table(name = "users")
public class User {
@Id
@Column(name = "pid")
private Long pid;
@Column(name = "login")
private String login;
@ManyToOne
@JoinColumn(name = "fk_department")
private Department department;
}
@Entity
@Table(name = "departments")
public class Department {
@Id
@Column(name = "pid")
private Long pid;
@Column(name = "name")
private String name;
}
Criteria criteria = session.createCriteria(User.class, "u");
criteria.createAlias("u.department", "d", JoinType.LEFT_OUTER_JOIN);
criteria.setProjection(Projections.projectionList()
.add(Projections.property("u.login").as("login"))
.add(Projections.property("d.name").as("department.name")));
List<User> users = criteria
.setResultTransformer(new FluentHibernateResultTransformer(User.class))
.list();Please, don't forget to specify projection aliases.
It is impossible with Hibernate 5 to use Transformers.aliasToBean(SomeDto.class) the same way as
it is used with Hibernate 3 — without the aliases with the quotes (a more deep explanation), but it is possible using FluentHibernateResultTransformer. This code works pretty well:
List<User> users = session.createSQLQuery("select login from users")
.setResultTransformer(new FluentHibernateResultTransformer(User.class))
.list();The transformer can be used for a native SQL with the nested projections (opposite HQL). It is need to use the aliases with the quotes in this case:
String sql = "select u.login, d.name as \"department.name\" "
+ "from users u left outer join departments d on u.fk_department = d.pid";
List<User> users = session.createSQLQuery(sql)
.setResultTransformer(new FluentHibernateResultTransformer(User.class))
.list();Sometimes it is convenient using complex search criteries to add an alias multiple times. In such situations Hibernate generates the org.hibernate.QueryException: duplicate alias exception . There is a utility class to solve this problem: Aliases. This code with alias duplicates working without errors:
Criteria criteria = session.createCriteria(User.class, "u");
Aliases aliases = Aliases.create()
.add("u.department", "d", JoinType.LEFT_OUTER_JOIN)
.add("u.department", "d", JoinType.LEFT_OUTER_JOIN);
criteria.add(Restrictions.isNotNull("d.name"));
aliases.addToCriteria(criteria);
List<User> users = criteria.list();Get all users
List<User> users = H.<User> request(User.class).list();Getting a user with a login my_login
final String loginToFind = "my_login";
User user = H.<User> request(User.class).eq("login", loginToFind).first();Get all users, but only with login and id properties are filled (other properties will be null).
List<User> users = H.<User> request(User.class).proj("login").proj("id")
.transform(User.class).list();- A console project with a lot of query examples
- A console project using Spring to configure fluent-hibernate
- A simply console Eclipse project. This project uses Hibernate 5 and MySQL. It has a very simply Eclipse structure (without Gradle stuff).
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