Copy specific fields by using BeanUtils.copyProperties?

Question

springframework.beans.BeanUtils is very useful to copy objects, and I use the \"ignoreProperties\" option frequently. However, sometimes I want to copy only spe

Answer 1

You can use the BeanWrapper technology. Here's a sample implementation:

public static void copyProperties(Object src, Object trg, Iterable props) {

    BeanWrapper srcWrap = PropertyAccessorFactory.forBeanPropertyAccess(src);
    BeanWrapper trgWrap = PropertyAccessorFactory.forBeanPropertyAccess(trg);

    props.forEach(p -> trgWrap.setPropertyValue(p, srcWrap.getPropertyValue(p)));

}

Or, if you really, really want to use BeanUtils, here's a solution. Invert the logic, gather excludes by comparing the full property list with the includes:

public static void copyProperties2(Object src, Object trg, Set props) {
    String[] excludedProperties = 
            Arrays.stream(BeanUtils.getPropertyDescriptors(src.getClass()))
                  .map(PropertyDescriptor::getName)
                  .filter(name -> !props.contains(name))
                  .toArray(String[]::new);

    BeanUtils.copyProperties(src, trg, excludedProperties);
}