What's wrong with my custom type for JPA/Hibernate?

Question

My custom type is (no default constructor!):

package com.XXX.common;
public class Email implements Serializable {
  private String e;
  public Email(String str) {
    e = str;
  }
}

My entity in Hibernate 3.5.6:

package com.XXX.persistence;
import com.XXX.common;
@Entity
@TypeDef(
  name = "email",
  defaultForType = Email.class,
  typeClass = Email.class
)
public class User {
  @Id private Integer id;
  @Type(type = "email")
  private Email email;
}

Hibernate says:

org.hibernate.MappingException: Could not determine type for:
com.XXX.common.Email, at table: user, for columns: 
[org.hibernate.mapping.Column(email)]

What am I doing wrong?

Answer 1

typeClass must point to something that extends UserType (this handler class contains the mapping from and to the database).

Answer 2

My custom type is (no default constructor!) (...)

A custom type must implement one of the interfaces from org.hibernate.usertype (implementing UserType would be enough for your specific example), your Email class is NOT a custom type. In other words, you'll need to create some EmailType class that Hibernate will use to persist a field or property of type Email.

PS: There is IMO not much value at wrapping a String with a class but let's say it was an example.

References

• Hibernate Core Reference Guide
  • 5.2.3. Custom value types

Resources

• Hibernate CompositeUserType and Annotations
• user_type examples on the Hibernate Wiki