JPA 2.1 - How to implement an Attribute Converter (http://www.thoughts-on-java.org/2013/10/jpa-21-how-to-implement-type-converter.html)

ColorConverter.java

package blog.thoughts.on.java.jpa21.converter;

import java.awt.Color;

import javax.persistence.AttributeConverter;
import javax.persistence.Converter;

@Converter
public class ColorConverter implements AttributeConverter<Color, String> {

 private static final String SEPARATOR = "\\|";

 /**
  * Convert Color object to a String 
  * with format red|green|blue|alpha
  */
 @Override
 public String convertToDatabaseColumn(Color color) {
  StringBuilder sb = new StringBuilder();
  sb.append(color.getRed()).append(SEPARATOR)
     .append(color.getGreen())
     .append(SEPARATOR)
     .append(color.getBlue())
     .append(SEPARATOR)
     .append(color.getAlpha());
  return sb.toString();
 }

 /**
  * Convert a String with format red|green|blue|alpha
  * to a Color object
  */
 @Override
 public Color convertToEntityAttribute(String colorString) {
  String[] rgb = colorString.split(SEPARATOR);
  return new Color(Integer.parseInt(rgb[0]), 
      Integer.parseInt(rgb[1]),
      Integer.parseInt(rgb[2]), 
      Integer.parseInt(rgb[3]));
 }

}

RectangleEntity.java

@Entity
public class RectangleEntity
{

   @Id
   @GeneratedValue(strategy = GenerationType.IDENTITY)
   private Integer id;

   @Column
   private Integer x;

   @Column
   private Integer y;

   @Column
   @Convert(converter = ColorConverter.class)
   private Color color;

   ...
}