java 对象复制 java对象复制非空属性

//1、使用更新对象的非空值去覆盖待更新对象
StringUtils.copyPropertiesIgnoreNull(device, dev);   //用device对象去覆盖dev对象


复制属性：将attr实体中的属性一一拷贝给attrEntity 实体，名字要一致。
eg:

@Override
public void saveAttr(AttrVo attr) {
    AttrEntity attrEntity = new AttrEntity();
    BeanUtils.copyProperties(attr, attrEntity);
    this.save(attrEntity);
}


eg:

@Override
    public void deleteRelation(AttrGroupRelationVo[] vos) {
//        relationDao.delete(new QueryWrapper<>().eq("attr_id", 1L).eq("attr_group_id", 1L));
        List<AttrAttrgroupRelationEntity> entities = Arrays.asList(vos).stream().map((item) -> {
            AttrAttrgroupRelationEntity relationEntity = new AttrAttrgroupRelationEntity();
            BeanUtils.copyProperties(item, relationEntity);
            return relationEntity;
        }).collect(Collectors.toList());
        relationDao.deleteBatchRelation(entities);
    }

//源码

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

//2、使用更新对象的非空值去覆盖待更新对象
实体拷贝：

UserDTO o = BeanUtil.copyProperties(user, UserDTO.class);

@Data
public class UserDTO {
private Long id;
    private String nickName;
    private String icon;
}

@Data
@EqualsAndHashCode(callSuper = false)
@Accessors(chain = true)
@TableName("tb_user")
public class User implements Serializable {

private static final long serialVersionUID = 1L;

    /**
     * 主键
     */
    @TableId(value = "id", type = IdType.AUTO)
private Long id;

    /**
     * 手机号码
     */
    private String phone;

    /**
     * 密码，加密存储
     */
    private String password;

    /**
     * 昵称，默认是随机字符
     */
    private String nickName;

    /**
     * 用户头像
     */
    private String icon = "";

    /**
     * 创建时间
     */
    private LocalDateTime createTime;

    /**
     * 更新时间
     */
    private LocalDateTime updateTime;


}