BeanUtils not works for chain setter

Question

e.g.

class tester
{
    @Test
    public void testBeanUtils() throws InvocationTargetException, IllegalAccessException, NoSuchMethodException
    {
        S         


        

Answer 1

In my project we use chained accessors across the board, so setting chain=false was not an option. I ended up writing my own introspector, which is similar to the one recommended by @mthielcke, and may be registered in the same way.

Introspector

import org.apache.commons.beanutils.BeanIntrospector;
import org.apache.commons.beanutils.IntrospectionContext;

import java.beans.IntrospectionException;
import java.beans.Introspector;
import java.beans.PropertyDescriptor;
import java.lang.reflect.Method;
import java.lang.reflect.Modifier;
import java.util.HashMap;
import java.util.Locale;
import java.util.Map;
import java.util.stream.Stream;

import lombok.extern.slf4j.Slf4j;

/**
 * Allows {@link org.apache.commons.beanutils.BeanUtils#copyProperties(Object, Object)} to copy properties across beans whose
 * properties have been made fluent through Lombok
 * {@link lombok.experimental.Accessors}, {@link lombok.Setter} and {@link lombok.Getter} annotations.
 *
 * @author izilotti
 */
@Slf4j
public class LombokPropertyBeanIntrospector implements BeanIntrospector {

    /**
     * Performs introspection. This method scans the current class's methods for property write and read methods which have been
     * created by the Lombok annotations.
     *
     * @param context The introspection context.
     */
    @Override
    public void introspect(final IntrospectionContext context) {
        getLombokMethods(context).forEach((propertyName, methods) -> {
            if (methods[0] != null && methods[1] != null) {
                final PropertyDescriptor pd = context.getPropertyDescriptor(propertyName);
                try {
                    if (pd == null) {
                        PropertyDescriptor descriptor = new PropertyDescriptor(propertyName, methods[1], methods[0]);
                        context.addPropertyDescriptor(descriptor);
                    }
                } catch (final IntrospectionException e) {
                    log.error("Error creating PropertyDescriptor for {}. Ignoring this property.", propertyName, e);
                }
            }
        });
    }

    private Map getLombokMethods(IntrospectionContext context) {
        Map lombokPropertyMethods = new HashMap<>(); // property name, write, read
        Stream.of(context.getTargetClass().getMethods())
                .filter(this::isNotJavaBeanMethod)
                .forEach(method -> {
                    if (method.getReturnType().isAssignableFrom(context.getTargetClass()) && method.getParameterCount() == 1) {
                        log.debug("Found mutator {} with parameter {}", method.getName(), method.getParameters()[0].getName());
                        final String propertyName = propertyName(method);
                        addWriteMethod(lombokPropertyMethods, propertyName, method);
                    } else if (!method.getReturnType().equals(Void.TYPE) && method.getParameterCount() == 0) {
                        log.debug("Found accessor {} with no parameter", method.getName());
                        final String propertyName = propertyName(method);
                        addReadMethod(lombokPropertyMethods, propertyName, method);
                    }
                });
        return lombokPropertyMethods;
    }

    private void addReadMethod(Map lombokPropertyMethods, String propertyName, Method readMethod) {
        if (!lombokPropertyMethods.containsKey(propertyName)) {
            Method[] writeAndRead = new Method[2];
            lombokPropertyMethods.put(propertyName, writeAndRead);
        }
        lombokPropertyMethods.get(propertyName)[1] = readMethod;
    }

    private void addWriteMethod(Map lombokPropertyMethods, String propertyName, Method writeMethod) {
        if (!lombokPropertyMethods.containsKey(propertyName)) {
            Method[] writeAndRead = new Method[2];
            lombokPropertyMethods.put(propertyName, writeAndRead);
        }
        lombokPropertyMethods.get(propertyName)[0] = writeMethod;
    }

    private String propertyName(final Method method) {
        final String methodName = method.getName();
        return (methodName.length() > 1) ? Introspector.decapitalize(methodName) : methodName.toLowerCase(Locale.ENGLISH);
    }

    private boolean isNotJavaBeanMethod(Method method) {
        return !isGetter(method) || isSetter(method);
    }

    private boolean isGetter(Method method) {
        if (Modifier.isPublic(method.getModifiers()) && method.getParameterTypes().length == 0) {
            if (method.getName().matches("^get[A-Z].*") && !method.getReturnType().equals(Void.TYPE)) {
                return true;
            }
            return method.getName().matches("^is[A-Z].*") && method.getReturnType().equals(Boolean.TYPE);
        }
        return false;
    }

    private boolean isSetter(Method method) {
        return Modifier.isPublic(method.getModifiers())
                && method.getReturnType().equals(Void.TYPE)
                && method.getParameterTypes().length == 1
                && method.getName().matches("^set[A-Z].*");
    }

}

Registration

PropertyUtils.addBeanIntrospector(new LombokPropertyBeanIntrospector());
BeanUtils.copyProperties(dest, origin);