『博客开发日记』之获取通知列表接口的实现

本文最后更新于 2026年5月28日 晚上

获取通知列表接口的实现

获取通知列表接口的需求

这是前台获取通知列表的接口

前台仅展示已发布通知；未登录用户只能看全体通知，登录用户还能看发给自己的指定通知

如果是指定用户的话通知只能是指定的用户才能看到

按发布时间倒序排序

分页查询

查询发布人的名字并回填

如果当前用户已登录，再查询并回填阅读状态

未读优先，已读在后；同状态下保持发布时间倒序

代码实现

前期准备

用 EasyCode 插件生成需要的文件

在 NoticeController 中添加接口

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/**
 * 前台通知相关接口
 */
@RestController
@Api(tags = "通知", description = "前台通知相关接口")
public class NoticeController
{
    @Autowired
    private NoticeService noticeService;

    @GetMapping("/notice/list")
    @SystemLog(businessName = "获取通知列表接口")
    @ApiOperation(value = "获取通知列表接口", notes = "分页查询通知列表", response = PageVo.class)
    @ApiImplicitParams({
            @ApiImplicitParam(name = "pageNum", value = "页号", dataType = "int", paramType = "query"),
            @ApiImplicitParam(name = "pageSize", value = "每页数量", dataType = "int", paramType = "query")
    })
    public ResponseResult<PageVo> getNoticeList(Integer pageNum, Integer pageSize)
    {
        return noticeService.getNoticeList(pageNum, pageSize);
    }

}

创建 BlogNoticeListVo 

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/**
 * 前台通知Vo
 */
@Data
@AllArgsConstructor
@NoArgsConstructor
@Accessors(chain = true)
@ApiModel(description = "前台通知列表响应对象")
public class BlogNoticeListVo
{
    @ApiModelProperty(value = "通知id", example = "6")
    private Long id;

    @ApiModelProperty(value = "通知标题", example = "这里是标题")
    private String title;

    @ApiModelProperty(value = "通知内容", example = "这里是内容")
    private String content;

    @ApiModelProperty(value = "通知类型（关联字典编码：notice_type）", example = "系统维护")
    private Integer type;

    @ApiModelProperty(value = "通知等级（字典code：notice_level）", example = "M")
    private String level;

    @TableField(exist = false)
    @ApiModelProperty(value = "读取状态（0: 未读, 1: 已读）", example = "0")
    private String isRead;

    @ApiModelProperty(value = "发布人名字", example = "云梦泽")
    private String publisherName;

    @TableField(fill = FieldFill.INSERT_UPDATE)
    @ApiModelProperty(value = "发布时间", example = "2024-01-01 12:00:00")
    private Date publishTime;
}

添加常量

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/**
 *  目标类型：指定用户
 */
public static final String TARGET_TYPE_IS_SPECIFIED = "2";

在 NoticeServiceImpl 中

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@Autowired
private SysNoticeUserService sysNoticeUserService;

@Autowired
private SysUserService sysUserService;

//获取通知列表
@Override
public ResponseResult<PageVo> getNoticeList(Integer pageNum, Integer pageSize)
{
    Long userId = SecurityUtils.getUserId();

    //前台仅展示已发布通知；未登录用户只能看全体通知，登录用户还能看发给自己的指定通知
    LambdaQueryWrapper<SysNotice> queryWrapper = new LambdaQueryWrapper<>();
    queryWrapper.eq(SysNotice::getStatus, SystemConstants.NOTICE_STATUS_PUBLISHED)
            .eq(SysNotice::getDelFlag, SystemConstants.STATUS_NORMAL);
    if (userId == null) {
        queryWrapper.eq(SysNotice::getTargetType, SystemConstants.TARGET_TYPE_IS_ALL);
    } else {
        queryWrapper.and(wrapper -> wrapper
                .eq(SysNotice::getTargetType, SystemConstants.TARGET_TYPE_IS_ALL)
                .or(orWrapper -> orWrapper
                        .eq(SysNotice::getTargetType, SystemConstants.TARGET_TYPE_IS_SPECIFIED)
                        .apply("find_in_set({0}, target_user_ids)", userId)));
    }

    //按发布时间倒序排序
    queryWrapper.orderByDesc(SysNotice::getPublishTime);

    //分页查询
    Page<SysNotice> page = new Page<>(pageNum, pageSize);
    this.page(page, queryWrapper);

    List<SysNotice> noticeList = page.getRecords();

    //实体转换为Vo
    List<BlogNoticeListVo> noticeListVos = BeanCopyUtils.copyBeanList(noticeList, BlogNoticeListVo.class);

    //查询发布人的名字并回填
    List<Long> publisherIds = noticeList.stream()
            .map(SysNotice::getPublisherId)
            .filter(Objects::nonNull)
            .distinct()
            .collect(Collectors.toList());
    Map<Long, String> publisherNameMap = new HashMap<>();
    if (!publisherIds.isEmpty()) {
        List<SysUser> publisherList = sysUserService.listByIds(publisherIds);
        publisherNameMap = publisherList.stream()
                .collect(Collectors.toMap(SysUser::getId, user -> StringUtils.hasText(user.getNickname()) ? user.getNickname() : user.getUsername(), (oldVal, newVal) -> oldVal));
    }

    //查询指定接收人的名字并回填
    Map<Long, String> targetUserNameMap = new HashMap<>();
    List<Long> targetUserIds = noticeList.stream()
            .filter(notice -> SystemConstants.TARGET_TYPE_IS_SPECIFIED.equals(notice.getTargetType()))
            .map(SysNotice::getTargetUserIds)
            .filter(StringUtils::hasText)
            .flatMap(targetUserIdsStr -> Arrays.stream(targetUserIdsStr.split(",")))
            .map(String::trim)
            .filter(StringUtils::hasText)
            .map(Long::valueOf)
            .distinct()
            .collect(Collectors.toList());
    if (!targetUserIds.isEmpty()) {
        List<SysUser> targetUserList = sysUserService.listByIds(targetUserIds);
        targetUserNameMap = targetUserList.stream()
                .collect(Collectors.toMap(SysUser::getId, user -> StringUtils.hasText(user.getNickname()) ? user.getNickname() : user.getUsername(), (oldVal, newVal) -> oldVal));
    }

    //将接收人名字集合封装进 VO
    for (int i = 0; i < noticeList.size(); i++)
    {
        SysNotice notice = noticeList.get(i);
        BlogNoticeListVo noticeListVo = noticeListVos.get(i);
        noticeListVo.setPublisherName(publisherNameMap.get(notice.getPublisherId()));
        noticeListVo.setTargetUserIds(notice.getTargetUserIds());
        if (SystemConstants.TARGET_TYPE_IS_SPECIFIED.equals(notice.getTargetType()) && StringUtils.hasText(notice.getTargetUserIds())) {
            List<String> targetNames = Arrays.stream(notice.getTargetUserIds().split(","))
                    .map(String::trim)
                    .filter(StringUtils::hasText)
                    .map(Long::valueOf)
                    .map(targetUserNameMap::get)
                    .filter(StringUtils::hasText)
                    .collect(Collectors.toList());
            noticeListVo.setTargetName(targetNames);
        }
    }

    //默认未读
    for (BlogNoticeListVo noticeListVo : noticeListVos) {
        noticeListVo.setIsRead(SystemConstants.NOTICE_NOT_READ);
    }

    //如果当前用户已登录，再查询并回填阅读状态
    if (userId != null && !noticeList.isEmpty()) {
        List<Long> noticeIds = noticeList.stream().map(SysNotice::getId).collect(Collectors.toList());
        List<SysNoticeUser> noticeUserList = sysNoticeUserService.list(new LambdaQueryWrapper<SysNoticeUser>()
                .eq(SysNoticeUser::getUserId, userId)
                .in(SysNoticeUser::getNoticeId, noticeIds));

        Map<Long, String> noticeReadMap = noticeUserList.stream()
                .collect(Collectors.toMap(SysNoticeUser::getNoticeId, SysNoticeUser::getIsRead, (oldVal, newVal) -> oldVal));

        for (BlogNoticeListVo noticeListVo : noticeListVos) {
            noticeListVo.setIsRead(noticeReadMap.getOrDefault(noticeListVo.getId(), SystemConstants.NOTICE_NOT_READ));
        }
        
        //未读优先，已读在后；同状态下保持发布时间倒序
        noticeListVos.sort(Comparator.comparing((BlogNoticeListVo vo) -> SystemConstants.NOTICE_IS_READ.equals(vo.getIsRead()))
                .thenComparing(BlogNoticeListVo::getPublishTime, Comparator.nullsLast(Comparator.reverseOrder())));
    }

    PageVo pageVo = new PageVo(noticeListVos, page.getTotal());
    return ResponseResult.okResult(pageVo);
}

PS:该系列只做为作者学习开发项目做的笔记用

不一定符合读者来学习，仅供参考

预告

后续会记录博客的开发过程

每次学习会做一份笔记来进行发表

“一花一世界，一叶一菩提”

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欢迎访问我的个人网站：https://hgt12.github.io/

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『博客开发日记』之获取通知列表接口的实现
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作者
云梦泽
发布于
2026年5月28日
更新于
2026年5月28日
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