问答社区-关注列表、粉丝列表
需求：
业务层
- 查询某个用户关注的人，支持分页
- 查询某个用户的粉丝，支持分页
表现层
- 处理“查询关注的人”、“查询粉丝”请求
- 编写“查询关注的人”、“查询粉丝”模板
1、followService新增，查询粉丝列表、关注列表的方法，返回list
//查询某用户关注的人
public List<Map<String, Object>> findFollowees(int userId, int offset, int limit) {
String followeeKey = RedisKeyUtil.getFolloweeKey(userId, ENTITY_TYPE_USER);
Set<Integer> targetIds = redisTemplate.opsForZSet().reverseRange(followeeKey, offset, offset + limit - 1);
if (targetIds == null) {
return null;
}
List<Map<String, Object>> list = new ArrayList<>();
for (Integer targetId : targetIds) {
Map<String, Object> map = new HashMap<>();
User user = userService.findUserById(targetId);
map.put("user", user);
Double score = redisTemplate.opsForZSet().score(followeeKey, targetId);
map.put("followTime", new Date(score.longValue()));
list.add(map);
}
return list;
}
//查询某用户的粉丝
public List<Map<String, Object>> findFollowers(int userId, int offset, int limit) {
String followerKey = RedisKeyUtil.getFollowerKey(ENTITY_TYPE_USER, userId);
Set<Integer> targetIds = redisTemplate.opsForZSet().reverseRange(followerKey, offset, offset + limit - 1);
if (targetIds == null) {
return null;
}
List<Map<String, Object>> list = new ArrayList<>();
for (Integer targetId : targetIds) {
Map<String, Object> map = new HashMap<>();
User user = userService.findUserById(targetId);
map.put("user", user);
Double score = redisTemplate.opsForZSet().score(followerKey, targetId);
map.put("followTime", new Date(score.longValue()));
list.add(map);
}
return list;
}2、controller处理“查询关注的人”、“查询粉丝”请求
//关注列表
@RequestMapping(value = "/followees/{userId}", method = RequestMethod.GET)
public String getFollowees(@PathVariable("userId") int userId, Model model, Page page) {
User user = userService.findUserById(userId);
if (user == null) {
throw new RuntimeException("该用户不存在!");
}
model.addAttribute("user", user);
page.setLimit(7);
page.setPath("/followees/" + userId);
page.setRows((int) followService.findFolloweeCount(userId, ENTITY_TYPE_USER));
List<Map<String, Object>> followees = followService.findFollowees(userId, page.getOffset(), page.getLimit());
if (followees != null) {
for (Map<String, Object> map : followees) {
User u = (User) map.get("user");
map.put("hasFollowed", hasFollowed(u.getId()));
System.out.println(u.toString());
}
}
model.addAttribute("users", followees);
return "/site/followee";
}
//粉丝列表
@RequestMapping(value = "/followers/{userId}", method = RequestMethod.GET)
public String getFollowers(@PathVariable("userId") int userId, Model model, Page page) {
User user = userService.findUserById(userId);
if (user == null) {
throw new RuntimeException("该用户不存在!");
}
model.addAttribute("user", user);
page.setLimit(7);
page.setPath("/followers/" + userId);
page.setRows((int) followService.findFollowerCount(ENTITY_TYPE_USER, userId));
List<Map<String, Object>> followers = followService.findFollowers(userId, page.getOffset(), page.getLimit());
if (followers != null) {
for (Map<String, Object> map : followers) {
User u = (User) map.get("user");
map.put("hasFollowed", hasFollowed(u.getId()));
}
}
model.addAttribute("users", followers);
return "/site/follower";
}
private boolean hasFollowed(int userId) {
if (hostHolder.getUser() == null) {
return false;
}
return followService.hasFollowed(hostHolder.getUser().getId(), ENTITY_TYPE_USER, userId);
}3、表现层页面
<div class="position-relative">
<!-- 选项 -->
<ul class="nav nav-tabs mb-3">
<li class="nav-item">
<a class="nav-link position-relative active" th:href="@{|/followees/${user.id}|}">
<i class="text-info" th:utext="${user.username}">Nowcoder</i> 关注的人</a>
</li>
<li class="nav-item">
<a class="nav-link position-relative" th:href="@{|/followers/${user.id}|}">关注 <i class="text-info" th:utext="${user.username}">Nowcoder</i> 的人</a>
</li>
</ul>
<a th:href="@{|/user/profile/${user.id}|}" class="text-muted position-absolute rt-0">返回个人主页></a>
</div>
<!-- 关注列表 -->
<ul class="list-unstyled">
<li class="media pb-3 pt-3 mb-3 border-bottom position-relative" th:each="map:${users}">
<a th:href="@{|/user/profile/${map.user.id}|}">
<img th:src="${map.user.headerUrl}" class="mr-4 rounded-circle user-header" alt="用户头像" >
</a>
<div class="media-body">
<h6 class="mt-0 mb-3">
<span class="text-success" th:utext="${map.user.username}">落基山脉下的闲人</span>
<span class="float-right text-muted font-size-12">关注于 <i th:text="${#dates.format(map.followTime,'yyyy-MM-dd HH:mm:ss')}">2019-04-28 14:13:25</i></span>
</h6>
<div>
<input type="hidden" id="entityId" th:value="${map.user.id}">
<button type="button" th:class="|btn ${map.hasFollowed?'btn-secondary':'btn-info'} btn-sm float-right follow-btn|"
th:if="${loginUser!=null&&loginUser.id!=map.user.id}" th:text="${map.hasFollowed?'已关注':'关注TA'}">关注TA</button>
</div>
</div>
</li>
</ul>总结：
简单说就是从Redis中把数据拿出来，通过里面的userid查询到每个用户，将用户放到hashmap中，再将返回list集合
当处理前端传过来的请求的时候，先进行判断，用户是否存在，在返回之前再判断是否关注了，接着再传递回模板
