问答社区-关注功能
需求：
- 开发关注、取消关注功能
- 统计用户的关注数、粉丝数
关键：
- 若A关注了B，则A是B的follower（粉丝），B是A的followee（目标）
- 关注的目标可以是用户、帖子、题目等，在实现的时候将这些目标抽象为实体
1、设置新的RedisKey,用zset存储
/**
* 某个用户关注的实体(用户、帖子等)
* 格式：followee:userId:entityType -> zset(entityId,now)
*/
public static String getFolloweeKey(int userId, int entityType) {
return PREFIX_FOLLOWEE + SPLIT + userId + SPLIT + entityType;
}
/**
* 某个实体拥有的粉丝
* follower:entityType:entityId ->zset(userId,now)
*/
public static String getFollowerKey(int entityType,int entityId){
return PREFIX_FOLLOWER + SPLIT + entityType + SPLIT + entityId;
}2、在service新增方法，关注、取消关注、关注数量、粉丝数量、是否关注
@Service
public class FollowService implements CommunityConstant {
@Autowired
private RedisTemplate redisTemplate;
@Autowired
private UserService userService;
//关注
public void follow(int userId, int entityType, int entityId) {
redisTemplate.execute(new SessionCallback() {
@Nullable
@Override
public Object execute(RedisOperations redisOperations) throws DataAccessException {
String followeeKey = RedisKeyUtil.getFolloweeKey(userId, entityType);
String followerKey = RedisKeyUtil.getFollowerKey(entityType, entityId);
redisOperations.multi();
redisOperations.opsForZSet().add(followeeKey, entityId, System.currentTimeMillis());
redisOperations.opsForZSet().add(followerKey, userId, System.currentTimeMillis());
return redisOperations.exec();
}
});
}
//取消关注
public void unfollow(int userId, int entityType, int entityId) {
redisTemplate.execute(new SessionCallback() {
@Nullable
@Override
public Object execute(RedisOperations redisOperations) throws DataAccessException {
String followeeKey = RedisKeyUtil.getFolloweeKey(userId, entityType);
String followerKey = RedisKeyUtil.getFollowerKey(entityType, entityId);
redisOperations.multi();
redisOperations.opsForZSet().remove(followeeKey, entityId);
redisOperations.opsForZSet().remove(followerKey, userId);
return redisOperations.exec();
}
});
}
//查询关注的实体的数量
public long findFolloweeCount(int userId, int entityType) {
String followeeKey = RedisKeyUtil.getFolloweeKey(userId, entityType);
return redisTemplate.opsForZSet().zCard(followeeKey);
}
//查询实体粉丝数量
public long findFollowerCount(int entityType, int entityId) {
String followerKey = RedisKeyUtil.getFollowerKey(entityType, entityId);
return redisTemplate.opsForZSet().zCard(followerKey);
}
//查询当前用户是否已关注该实体
public boolean hasFollowed(int userId, int entityType, int entityId) {
String followeeKey = RedisKeyUtil.getFolloweeKey(userId, entityType);
return redisTemplate.opsForZSet().score(followeeKey, entityId) != null;
}
}3、在新增followcontroller，实现follow和unfollow方法，并在usercontroller中把粉丝数量、关注数量、是否关注的信息传过去
followController
@Controller
public class FollowController implements CommunityConstant {
@Autowired
private FollowService followService;
@Autowired
private HostHolder hostHolder;
@Autowired
private UserService userService;
@LoginRequired
@RequestMapping(value = "/follow", method = RequestMethod.POST)
@ResponseBody
public String follow(int entityType, int entityId) {
User user = hostHolder.getUser();
followService.follow(user.getId(), entityType, entityId);
return CommunityUtil.getJSONString(0, "已关注！");
}
@LoginRequired
@RequestMapping(value = "/unfollow", method = RequestMethod.POST)
@ResponseBody
public String unfollow(int entityType, int entityId) {
User user = hostHolder.getUser();
followService.unfollow(user.getId(), entityType, entityId);
return CommunityUtil.getJSONString(0, "已取消关注！");
}
}userController
//个人主页
@RequestMapping(value = "/profile/{userId}", method = RequestMethod.GET)
public String getProfilePage(@PathVariable("userId") int userId, Model model) {
User user = userService.findUserById(userId);
if (user == null) {
throw new RuntimeException("该用户不存在！");
}
//用户
model.addAttribute("user", user);
//点赞数量
int likeCount = likeService.findUserLikeCount(userId);
model.addAttribute("likeCount", likeCount);
//关注数量
long followeeCount = followService.findFolloweeCount(userId, ENTITY_TYPE_USER);
model.addAttribute("followeeCount", followeeCount);
//粉丝数量
long followerCount = followService.findFollowerCount(ENTITY_TYPE_USER, userId);
model.addAttribute("followerCount", followerCount);
//是否已关注
boolean hasFollowed = followService.hasFollowed(hostHolder.getUser().getId(), ENTITY_TYPE_USER, userId);
model.addAttribute("hasFollowed", hasFollowed);
return "/site/profile";
}4、前台html和js
把传递过来的值显示在页面上
这里要注意：
当用户是本人的时候，不显示关注按钮
当用户点击关注按钮之后，按钮更换样式，变成灰色
//html
<div class="media mt-5">
<img th:src="${user.headerUrl}" class="align-self-start mr-4 rounded-circle" alt="用户头像" style="width:50px;">
<div class="media-body">
<h5 class="mt-0 text-warning">
<span th:text="${user.username}">nowcoder</span>
<input type="hidden" id="entityId" th:value="${user.id}">
<button type="button" th:class="|btn ${hasFollowed?'btn-secondary':'btn-info'} btn-sm float-right mr-5 follow-btn|" th:text="${hasFollowed?'已关注':'关注TA'}" th:if="${loginUser!=null&&loginUser.id!=user.id}">关注TA</button>
</h5>
<div class="text-muted mt-3">
<span>注册于 <i class="text-muted" th:text="${#dates.format(user.createTime,'yyyy-MM-dd HH:mm:ss')}">2015-06-12 15:20:12</i></span>
</div>
<div class="text-muted mt-3 mb-5">
<span>关注了 <a class="text-primary" th:href="@{|/followees/${user.id}|}" th:text="${followeeCount}">5</a> 人</span>
<span class="ml-4">关注者 <a class="text-primary" th:href="@{|/followers/${user.id}|}" th:text="${followerCount}">123</a> 人</span>
<span class="ml-4">获得了 <i class="text-danger" th:text="${likeCount}">87</i> 个赞</span>
</div>
</div>
</div>//js
$(function(){
$(".follow-btn").click(follow);
});
function follow() {
var btn = this;
if($(btn).hasClass("btn-info")) {
// 关注TA
$.post(
CONTEXT_PATH + "/follow",
{"entityType":3,"entityId":$(btn).prev().val()},
function (data) {
data = $.parseJSON(data);
if(data.code == 0){
window.location.reload();
}else{
alert(data.msg);
}
}
)
// $(btn).text("已关注").removeClass("btn-info").addClass("btn-secondary");
} else {
// 取消关注
// $(btn).text("关注TA").removeClass("btn-secondary").addClass("btn-info");
$.post(
CONTEXT_PATH + "/unfollow",
{"entityType":3,"entityId":$(btn).prev().val()},
function (data) {
data = $.parseJSON(data);
if(data.code == 0){
window.location.reload();
}else{
alert(data.msg);
}
}
)
}
}
