java jpa save method for assisting tools

Method java jpa save data tools

• Since some fields jpa method alone is not updated, Save method may update a data, but has the drawback that it will also update the field is empty up.
  If there is a utility class may be a non-empty data entity class findOne jpa mapped onto the data, and then save, it will be a lot easier as follows:

import com.alibaba.druid.util.StringUtils;
import org.springframework.beans.BeanUtils;
import org.springframework.beans.BeanWrapper;
import org.springframework.beans.BeanWrapperImpl;
import java.beans.PropertyDescriptor;
import java.util.HashSet;
import java.util.Objects;
import java.util.Set;

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<String> 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) {
        IdNameVo newvo=  new IdNameVo();
        newvo.setId("1");
        newvo.setName("更新后的实体类");
        newvo.setLevel(1);
        newvo.setParentId("0");
        IdNameVo old=  new IdNameVo();
        old.setId("1");
        old.setName("更新前的实体类");
        old.setLevel(2);
        old.setParentId("1");
        old.setIdx(4);
        old.setCode("123");
        System.out.println(old);
        UpdateUtil.copyNullProperties(newvo,old);
        System.out.println(old);
		//然后直接jpa的save(vo2)就可以了
    }
}

The resulting output is:

IdNameVo (id = 1, name = entity class before update, the parentId =. 1, Level = 2, IDX =. 4, Children = [], code = 123, coupon = null, couponId = null, PromotionId = null,
promotionType = null , searchType = null)
IdNameVo (ID =. 1, name entity class = updated, parentId = 0, level = 1 , idx = 4, children = [], code = 123, coupon = null, couponId = null, promotionId = null,
promotionType = null, searchType = null)