SpringのBeanUtils.copyPropertiesメソッド

public abstract class BeanUtils {

    //      

    public static void copyProperties(Object source, Object target) throws BeansException {
        copyProperties(source, target, null, (String[]) null);
    }

    public static void copyProperties(Object source, Object target, Class> editable) throws BeansException {
        copyProperties(source, target, editable, (String[]) null);
    }

    public static void copyProperties(Object source, Object target, String... ignoreProperties) throws BeansException {
        copyProperties(source, target, null, ignoreProperties);
    }

    private static void copyProperties(Object source, Object target,
            @Nullable Class> editable, 
            @Nullable String... ignoreProperties 
            ) throws BeansException {

        Assert.notNull(source, "Source must not be null");
        Assert.notNull(target, "Target must not be null");

        Class> actualEditable = target.getClass();
        if (editable != null) {
            if (!editable.isInstance(target)) {
                throw new IllegalArgumentException("Target class [" + target.getClass().getName() +
                        "] not assignable to Editable class [" + editable.getName() + "]");
            }
            actualEditable = editable;
        }
        //  target     ，    class   
        PropertyDescriptor[] targetPds = getPropertyDescriptors(actualEditable);
        //       
        List ignoreList = (ignoreProperties != null ? Arrays.asList(ignoreProperties) : null);

        //  target     
        for (PropertyDescriptor targetPd : targetPds) {
            //     
            Method writeMethod = targetPd.getWriteMethod();
            if (writeMethod != null && (ignoreList == null || !ignoreList.contains(targetPd.getName()))) {
                //  target    ，  source     
                PropertyDescriptor sourcePd = getPropertyDescriptor(source.getClass(), targetPd.getName());
                if (sourcePd != null) {
                    //  source      
                    Method readMethod = sourcePd.getReadMethod();
                    //                       ，        
                    if (readMethod != null &&
                            ClassUtils.isAssignable(writeMethod.getParameterTypes()[0], readMethod.getReturnType())) {
                        try {
                            //       public ，   accessible=true
                            if (!Modifier.isPublic(readMethod.getDeclaringClass().getModifiers())) {
                                readMethod.setAccessible(true);
                            }
                            Object value = readMethod.invoke(source);
                            //       public ，   accessible=true
                            if (!Modifier.isPublic(writeMethod.getDeclaringClass().getModifiers())) {
                                writeMethod.setAccessible(true);
                            }
                            //target.setXXX(source.getXXX())
                            writeMethod.invoke(target, value);
                        }
                        catch (Throwable ex) {
                            throw new FatalBeanException(
                                    "Could not copy property '" + targetPd.getName() + "' from source to target", ex);
                        }
                    }
                }
            }
        }
    }

    public static PropertyDescriptor[] getPropertyDescriptors(Class> clazz) throws BeansException {
        CachedIntrospectionResults cr = CachedIntrospectionResults.forClass(clazz);
        return cr.getPropertyDescriptors();
    }
}