What is the easiest way to ignore a JPA field during persistence

Question

I m essentially looking for a   Ignore  type annotation with which I can stop a particular field from being persisted  How can this be achieved

User · Answer

To ignore a field  annotate it with  Transient so it will not be mapped by hibernate   but then jackson will not serialize the field when converting to JSON   If you need mix JPA with JSON omit by JPA but still include in Jackson  use  JsonInclude     JsonInclude    Transient private String token    TIP   You can also use JsonInclude Include NON NULL and hide fields in JSON during deserialization when token    null    JsonInclude JsonInclude Include NON NULL   Transient private String token

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Apparently  using Hibernate5Module  the  Transient will not be serialize if using ObjectMapper  Removing will make it work  import javax persistence Transient   import org junit Test   import com fasterxml jackson annotation JsonInclude Include  import com fasterxml jackson core JsonProcessingException  import com fasterxml jackson databind ObjectMapper   import lombok Builder  import lombok Getter  import lombok Setter  import lombok extern slf4j Slf4j    Slf4j public class TransientFieldTest         Test     public void Print Json   throws JsonProcessingException            ObjectMapper objectEntityMapper   new ObjectMapper              objectEntityMapper registerModule new Hibernate5Module             objectEntityMapper setSerializationInclusion Include NON NULL            log info  quot object     quot   objectEntityMapper writeValueAsString                     SampleTransient builder                                   id  quot id quot                                   transientField  quot transientField quot                                   build                   Getter      Setter      Builder     private static class SampleTransient            private String id            Transient         private String transientField           private String nullField

User · Answer

Sometimes you want to    Serialize a column Ignore column from being persisted    Use  Column name    columnName   insertable   false  updatable   false   A good scenario is when a certain column is automatically calculated by using other column values

User · Answer

To ignore a field  annotate it with  Transient so it will not be mapped by hibernate  Source  Hibernate Annotations

User · Answer

Transient complies with your needs

User · Answer

To complete the above answers  I had the case using an XML mapping file where neither the  Transient nor transient worked    I had to put the transient information in the xml file    lt attributes gt             lt transient name  field    gt   lt  attributes gt

User · Answer

None of the above answers worked for me using Hibernate 5 2 10  Jersey 2 25 1 and Jackson 2 8 9  I finally found the answer  sort of  they reference hibernate4module but it works for 5 too  here  None of the Json annotations worked at all with  Transient  Apparently Jackson2 is  smart  enough to kindly ignore stuff marked with  Transient unless you explicitly tell it not to  The key was to add the hibernate5 module  which I was using to deal with other Hibernate annotations  and disable the USE TRANSIENT ANNOTATION feature in my Jersey Application   ObjectMapper jacksonObjectMapper   new ObjectMapper    Hibernate5Module jacksonHibernateModule   new Hibernate5Module    jacksonHibernateModule disable Hibernate5Module Feature USE TRANSIENT ANNOTATION   jacksonObjectMapper registerModule jacksonHibernateModule       Here is the dependency for the Hibernate5Module    lt dependency gt       lt groupId gt com fasterxml jackson datatype lt  groupId gt       lt artifactId gt jackson-datatype-hibernate5 lt  artifactId gt       lt version gt 2 8 9 lt  version gt   lt  dependency gt

User · Answer

There are multiple solutions depending on the entity attribute type  Basic attributes Consider you have the following account table   The account table is mapped to the Account entity like this   Entity name    quot Account quot   public class Account         Id     private Long id        ManyToOne     private User owner       private String iban       private long cents       private double interestRate       private Timestamp createdOn        Transient     private double dollars        Transient     private long interestCents        Transient     private double interestDollars        PostLoad     private void postLoad             this dollars   cents   100D           long months   createdOn toLocalDateTime                until LocalDateTime now    ChronoUnit MONTHS           double interestUnrounded       interestRate   100D     cents   months     12          this interestCents   BigDecimal valueOf interestUnrounded               setScale 0  BigDecimal ROUND HALF EVEN  longValue             this interestDollars   interestCents   100D               Getters and setters omitted for brevity    The basic entity attributes are mapped to table columns  so properties like id  iban  cents are basic attributes  But the dollars  interestCents  and interestDollars are computed properties  so you annotate them with  Transient to exclude them from SELECT  INSERT  UPDATE  and DELETE SQL statements   So  for basic attributes  you need to use  Transient in order to exclude a given property from being persisted   Associations Assuming you have the following post and post comment tables   You want to map the latestComment association in the Post entity to the latest PostComment entity that was added  To do that  you can use the  JoinFormula annotation   Entity name    quot Post quot    Table name    quot post quot   public class Post          Id     private Long id        private String title         ManyToOne fetch   FetchType LAZY       JoinFormula  quot   quot             quot SELECT pc id  quot             quot FROM post comment pc  quot             quot WHERE pc post id   id  quot             quot ORDER BY pc created on DESC  quot             quot LIMIT 1 quot         quot   quot       private PostComment latestComment          Getters and setters omitted for brevity    When fetching the Post entity  you can see that the latestComment is fetched  but if you want to modify it  the change is going to be ignored   So  for associations  you can use  JoinFormula to ignore the write operations while still allowing reading the association    MapsId Another way to ignore associations that are already mapped by the entity identifier is to use  MapsId  For instance  consider the following one-to-one table relationship   The PostDetails entity is mapped like this   Entity name    quot PostDetails quot    Table name    quot post details quot   public class PostDetails          Id     private Long id         Column name    quot created on quot       private Date createdOn         Column name    quot created by quot       private String createdBy         OneToOne fetch   FetchType LAZY       MapsId     private Post post        public PostDetails            public PostDetails String createdBy            createdOn   new Date            this createdBy   createdBy                Getters and setters omitted for brevity    Notice that both the id attribute and the post association map the same database column  which is the post details Primary Key column  To exclude the id attribute  the  MapsId annotation will tell Hibernate that the post association takes care of the table Primary Key column value   So  when the entity identifier and an association share the same column  you can use  MapsId to ignore the entity identifier attribute and use the association instead   Using insertable   false  updatable   false Another option is to use insertable   false  updatable   false for the association which you want to be ignored by Hibernate  For instance  we can map the previous one-to-one association like this   Entity name    quot PostDetails quot    Table name    quot post details quot   public class PostDetails         Id      Column name    quot post id quot       private Long id        Column name    quot created on quot       private Date createdOn        Column name    quot created by quot       private String createdBy        OneToOne      JoinColumn name    quot post id quot   insertable   false  updatable   false      private Post post         Getters and setters omitted for brevity      public void setPost Post post            this post   post          if  post    null                this id   post getId                       The insertable and updatable attributes of the  JoinColumn annotation will instruct Hibernate to ignore the post association since the entity identifier takes care of the post id Primary Key column

User · Answer

use  Transient to make JPA ignoring the field  but  Jackson will not serialize that field as well  to solve just add  JsonProperty an example  Transient  JsonProperty private boolean locked

User · Answer

This answer comes a little late  but it completes the response   In order to avoid a field from an entity to be persisted in DB one can use one of the two mechanisms    Transient - the JPA annotation marking a field as not persistable  transient keyword in java  Beware - using this keyword  will prevent the field to be used with any serialization mechanism from java  So  if the field must be serialized you d better use just the  Transient annotation

[java] What is the easiest way to ignore a JPA field during persistence?

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