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EclipseLink/UserGuide/JPA/Basic JPA Development/Mapping/Basic Mappings/Default Conversions and Converters/TypeConverter


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Elug api package icon.png Key API

@TypeConverter

@TypeConverter is an EclipseLink-specific annotation. You can use it to specify an org.eclipse.persistence.mappings.converters.TypeConversionConverter for modification of the data value(s) during the reading and writing of a mapped attribute.

 
 @Target({TYPE, METHOD, FIELD})
 @Retention(RUNTIME)
 public @interface TypeConverter {
    String name();
    Class dataType() default void.class;
    Class objectType() default void.class;
 }
@TypeConverter Annotation Attributes
Attribute Description Default Required?
name Set this attribute to the String name for your converter. Ensure that this name is unique across the persistence unit. Yes
dataType Set this attribute to the type stored in the database. void.class1 No
objectType Set the value of this attribute to the type stored on the entity. void.class1 No

1 The default is inferred from the type of the persistence field or property.


The following example shows how to use the @TypeConverter annotation to convert the Double value stored in the database to a Float value stored in the entity.

Example: @TypeConverter Annotation
 @Entity
 public class Employee implements Serializable{
     ...
     @TypeConverter (
         name="doubleToFloat",
         dataType=Double.class,
         objectType=Float.class,
     )
     @Convert("doubleToFloat")
     public Number getGradePointAverage() {
         return gradePointAverage;
     }
     ...
 }



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Version: 2.1.0
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