BeanUtils.copyProperties() 所有的空值不复制

第一种情况： 所有为空值的属性都不copy
直接上代码吧~

public class UpdateUtil {
    /**
     * 所有为空值的属性都不copy
     *
     * @param source
     * @param target
     */
    public static void copyNullProperties(Object source, Object target) {
        BeanUtils.copyProperties(source, target, getNullField(source));
    }

    /**
     * 获取属性中为空的字段
     *
     * @param target
     * @return
     */
    private static String[] getNullField(Object target) {
        BeanWrapper beanWrapper = new BeanWrapperImpl(target);
        PropertyDescriptor[] propertyDescriptors = beanWrapper.getPropertyDescriptors();
        Set notNullFieldSet = new HashSet<>();
        if (propertyDescriptors.length > 0) {
            for (PropertyDescriptor p : propertyDescriptors) {
                String name = p.getName();
                Object value = beanWrapper.getPropertyValue(name);
                if (Objects.isNull(value)) {
                    notNullFieldSet.add(name);
                }
            }
        }
        String[] notNullField = new String[notNullFieldSet.size()];
        return notNullFieldSet.toArray(notNullField);
    }

    public static void main(String[] args) {
        TopMenuConfigEntity topMenuConfigEntity1 = new TopMenuConfigEntity();
        topMenuConfigEntity1.setWardCode("cat");
        topMenuConfigEntity1.setTitle("animal");

        TopMenuConfigEntity topMenuConfigEntity2 = new TopMenuConfigEntity();
        topMenuConfigEntity2.setWardCode("dog");

        UpdateUtil.copyNullProperties(topMenuConfigEntity2,topMenuConfigEntity1);

        System.out.println(topMenuConfigEntity1.getTitle());
    }
}

执行main 方法后，topMenuConfigEntity1的title还是为原来的“animal”值，没有被topMenuConfigEntity2 的空值覆盖。

第二种情况：
原对象的属性有值，复制时指定某些字段不复制
调BeanUtils的这个方法

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

 public static void main(String[] args) {
        TopMenuConfigEntity topMenuConfigEntity1 = new TopMenuConfigEntity();
        topMenuConfigEntity1.setWardCode("cat");
        topMenuConfigEntity1.setTitle("animal");
        topMenuConfigEntity1.setCreateTime(new Date());

        TopMenuConfigEntity topMenuConfigEntity2 = new TopMenuConfigEntity();

        String[] ignoreArray = new String[]{"title","createTime"};
        BeanUtils.copyProperties(topMenuConfigEntity2,topMenuConfigEntity1,ignoreArray);
        System.out.println("title : "+topMenuConfigEntity2.getTitle() +";createTime :" + topMenuConfigEntity2.getCreateTime());

    }

topMenuConfigEntity2的title 和createTime为null,没有复制