Does Hibernate always need a setter when there is a getter?

Question

We have some Hibernate getter methods annotated with both @Column and @Basic.

We get an exception if we don't have the corresponding setter. Why is this?

In our case we are deriving the value returned from the getter (to get stored in the DB) and the setter has no functional purpose. So we just have an empty method to get around the error condition..

Just autogenerate model objects. Eclipse, Dali and/or Hibernatetools can do this in a few clicks. No need to spend hours on writing getters/setters nor worrying about its correctness and presence. — BalusC, Apr 20 '10 at 17:42

score 85 · Accepted Answer · answered Apr 20 '10 at 17:28

As others have mentioned, if you annotate a property getter method, then Hibernate uses the setter when reading values from the database. Basically, Hibernate assumes that anything that it is writing to the database will eventually need to be read from the database. This implies that if you annotate a getter, then it needs to call a setter when reading the object from the database.

You can make the setter private (Hibernate will use reflection to access the setter). This is great way to preserve the contract of your class while still using Hibernate for relational mapping.

If the field is derived from other properties in the class, then why are you storing it in the database? You can use the @Transient annotation to mark the field that it shouldn't be stored in the database. You can even use the @Formula annotation to have Hibernate derive the field for you (it does this by using the formula in the query it sends to the database).

`@Transient` annotation on the getter is all that is needed – mirelon Feb 19 '14 at 15:00 — mirelon, Feb 19 '14 at 15:00

score 12 · Answer 2 · edited Jan 18 '17 at 07:36

12

You should annotate your classes with the @Entity(access = AccessType.FIELD) and annotate your attributes. This should solve your problem. The setter is the best way to support refactoring. And what's the problem with having the little setter there.

edited Jan 18 '17 at 07:36

naXa stands with Ukraine

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answered Apr 20 '10 at 16:19

khmarbaise

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Just put the annotations to the attributes instead of the getter then it should work as well (Read the annotation doc about Access Type). – khmarbaise Apr 20 '10 at 16:22
No problem with having the setter per se.. it's just extra code.. we are only using Hibernate to write to the db, never to read.. – Marcus Leon Apr 20 '10 at 17:19
2

Bear in mind that changing the access type from property to field can have side effect. Hibernate will no longer use the getters and setters, but will access the fields directly via reflection, meaning if you have any special logic in your getters and setters, it will no longer be called. – Jherico Apr 20 '10 at 18:19
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I feel like they should never even have special logic implemented ;) – chzbrgla Feb 22 '12 at 15:52
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it shows me an error . it look like @Entity don't have any parameter name access. – Saif Nov 15 '14 at 07:37
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@Saif In this post not javax.persistence.Entity was mentioned, but org.hibernate.annotations.Entity. But after 4.1 version of Hibernate it's deprecated, so you could us @javax.persistence.Access(javax.persistence.AccessType.FIELD) – AlexB Apr 21 '17 at 08:16

score 10 · Answer 3 · edited Mar 12 '19 at 21:00

10

Set access="field" if you do not want to use setters:

<class name="com.demo.hibernate.Country" table="country">
  <id name="countryId" column="id" type="int">
    <generator class="increment" />
  </id>
  <property name="name" column="name" access="field" type="string" />
  <property name="countryCode" column="country_code" access="field" type="string" />
</class>

edited Mar 12 '19 at 21:00

Michael

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answered Dec 01 '14 at 21:11

vsingh

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score 1 · Answer 4 · answered Apr 20 '10 at 16:12

1

Hibernate uses set method to initialize the entity which you're reading from your DB.

Maybe, if you make access modifiers of entity fields default or protected or public then Hibernate will initialize fields directly without using setter (I read something about it but I'm not sure that it works). But using setter is much more preferred way.

answered Apr 20 '10 at 16:12

Roman

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The thing is we are only writing data to the db, never reading.. but I guess Hibernate doesn't know that ;) – Marcus Leon Apr 20 '10 at 17:18
Unfortunatelly no, "private" modifier doesn't force Hibernate to use setters :( – Andremoniy Oct 18 '13 at 10:43

score -1 · Answer 5 · answered Apr 20 '10 at 16:23

-1

If you don't use setters and use private attributes, Hibernate would have to retrieve Fields by reflection and do field.setAccessible(true). I don't think Hibernate does that.

I don't really know if we can tell to Hibernate to do that, but as far as i remember, default config is using setters... Put a log/sysout on a set and you'll see that it uses the setter.

answered Apr 20 '10 at 16:23

Sebastien Lorber

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-1 because if the field or property is private, Hibernate does exactly that (use field.setAccessible(true)). – Jim Hurne Apr 20 '10 at 17:29
Actually i'm pretty sure that while using JPA / entity beans with all private attributes, hibernate (3.4 i think) was using the setter... But perhaps if there is no setter it does that... don't know... – Sebastien Lorber Apr 21 '10 at 09:20

Does Hibernate always need a setter when there is a getter?

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