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，在实现时将这些目标抽象为实体。
也是将数据存储到redis中，实现统计
1. 在RedisKeyUtil.java中增加对应的粉丝方法
package com.nowcoder.community.util;
public class RedisKeyUtil {
private static final String SPLIT = ":";
private static final String PREFIX_ENTITY_LIKE = "like:entity";
private static final String PREFIX_USER_LIKE = "like:user";
private static final String PREFIX_FOLLOWEE = "followee";//声明两个前缀
private static final String PREFIX_FOLLOWER = "follower";//关注了某人，将目标存在下，
private static final String PREFIX_KAPTCHA = "kaptcha";
private static final String PREFIX_TICKET = "ticket";
private static final String PREFIX_USER = "user";
// 某个实体的赞
// like:entity:entityType:entityId -> set(userId)
public static String getEntityLikeKey(int entityType, int entityId) {
return PREFIX_ENTITY_LIKE + SPLIT + entityType + SPLIT + entityId;
}
// 某个用户的赞
// like:user:userId -> int
public static String getUserLikeKey(int userId) {
return PREFIX_USER_LIKE + SPLIT + userId;
}
// 某个用户关注的实体，拼key的方法，存的时候，存有序集合，zset可以排序
// followee:userId:entityType -> zset(entityId,now)；//某个用户关注某个实体，以当前时间排序，能应付更好的需求变化
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;
}
// 用户
public static String getUserKey(int userId) {
return PREFIX_USER + SPLIT + userId;
}
}
2. 开发相应的业务
package com.nowcoder.community.service;
import com.nowcoder.community.entity.User;
import com.nowcoder.community.util.CommunityConstant;
import com.nowcoder.community.util.RedisKeyUtil;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.dao.DataAccessException;
import org.springframework.data.redis.core.RedisOperations;
import org.springframework.data.redis.core.RedisTemplate;
import org.springframework.data.redis.core.SessionCallback;
import org.springframework.stereotype.Service;
import java.util.*;
@Service
public class FollowService implements CommunityConstant {
@Autowired
private RedisTemplate redisTemplate;//注入Redis相应的组件
@Autowired
private UserService userService;//将用户组件注入
public void follow(int userId, int entityType, int entityId) {
redisTemplate.execute(new SessionCallback() {//一项业务有两项存储，要保证其事务性
@Override
public Object execute(RedisOperations operations) throws DataAccessException {
String followeeKey = RedisKeyUtil.getFolloweeKey(userId, entityType);//关注是用户关注
String followerKey = RedisKeyUtil.getFollowerKey(entityType, entityId);
operations.multi();//启用事务，在中间做两次存储的操作
operations.opsForZSet().add(followeeKey, entityId, System.currentTimeMillis());//分数是当前时间，转成毫秒时间
operations.opsForZSet().add(followerKey, userId, System.currentTimeMillis());
return operations.exec();//执行事务
}
});
}
//取消关注的代码逻辑
public void unfollow(int userId, int entityType, int entityId) {
redisTemplate.execute(new SessionCallback() {
@Override
public Object execute(RedisOperations operations) throws DataAccessException {
String followeeKey = RedisKeyUtil.getFolloweeKey(userId, entityType);
String followerKey = RedisKeyUtil.getFollowerKey(entityType, entityId);
operations.multi();
operations.opsForZSet().remove(followeeKey, entityId);//与上一方法的区别只是将数据移除
operations.opsForZSet().remove(followerKey, userId);
return operations.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);
}
// 查询实体的粉丝的数量
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;
}
// 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;
}
}
3.视图层:FollowController.java
package com.nowcoder.community.controller;
import com.nowcoder.community.entity.Page;
import com.nowcoder.community.entity.User;
import com.nowcoder.community.service.FollowService;
import com.nowcoder.community.service.UserService;
import com.nowcoder.community.util.CommunityConstant;
import com.nowcoder.community.util.CommunityUtil;
import com.nowcoder.community.util.HostHolder;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.stereotype.Controller;
import org.springframework.ui.Model;
import org.springframework.web.bind.annotation.PathVariable;
import org.springframework.web.bind.annotation.RequestMapping;
import org.springframework.web.bind.annotation.RequestMethod;
import org.springframework.web.bind.annotation.ResponseBody;
import java.util.List;
import java.util.Map;
@Controller
public class FollowController implements CommunityConstant {
@Autowired
private FollowService followService;//注入service
@Autowired
private HostHolder hostHolder;
@Autowired
private UserService userService;
@RequestMapping(path = "/follow", method = RequestMethod.POST)//关注是一个异步请求
@ResponseBody
public String follow(int entityType, int entityId) {
User user = hostHolder.getUser();//获取当前登陆用户；
followService.follow(user.getId(), entityType, entityId);
return CommunityUtil.getJSONString(0, "已关注!");//异步请求，返回JSON
}
@RequestMapping(path = "/unfollow", method = RequestMethod.POST)//取消关注的逻辑类似
@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!");
}
@RequestMapping(path = "/followees/{userId}", method = RequestMethod.GET)
public String getFollowees(@PathVariable("userId") int userId, Page page, Model model) {
User user = userService.findUserById(userId);
if (user == null) {
throw new RuntimeException("该用户不存在!");
}
model.addAttribute("user", user);
page.setLimit(5);
page.setPath("/followees/" + userId);
page.setRows((int) followService.findFolloweeCount(userId, ENTITY_TYPE_USER));
List<Map<String, Object>> userList = followService.findFollowees(userId, page.getOffset(), page.getLimit());
if (userList != null) {
for (Map<String, Object> map : userList) {
User u = (User) map.get("user");
map.put("hasFollowed", hasFollowed(u.getId()));
}
}
model.addAttribute("users", userList);
return "/site/followee";
}
@RequestMapping(path = "/followers/{userId}", method = RequestMethod.GET)
public String getFollowers(@PathVariable("userId") int userId, Page page, Model model) {
User user = userService.findUserById(userId);
if (user == null) {
throw new RuntimeException("该用户不存在!");
}
model.addAttribute("user", user);
page.setLimit(5);
page.setPath("/followers/" + userId);
page.setRows((int) followService.findFollowerCount(ENTITY_TYPE_USER, userId));
List<Map<String, Object>> userList = followService.findFollowers(userId, page.getOffset(), page.getLimit());
if (userList != null) {
for (Map<String, Object> map : userList) {
User u = (User) map.get("user");
map.put("hasFollowed", hasFollowed(u.getId()));
}
}
model.addAttribute("users", userList);
return "/site/follower";
}
private boolean hasFollowed(int userId) {
if (hostHolder.getUser() == null) {
return false;
}
return followService.hasFollowed(hostHolder.getUser().getId(), ENTITY_TYPE_USER, userId);
}
}
这里演示关注某个用户
4. 在profile.html中调整，在profile.js文件中执行关注的操作
在CommunityConstant.java接口中添加“人”所代表的实体类型。
/**
* 实体类型: 用户
*/
int ENTITY_TYPE_USER = 3;
$(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()},//ID值从页面中显示
function(data) {
data = $.parseJSON(data);//处理从服务器返回的结果，先转成JSON对象
if(data.code == 0) {//若服务器返回的结果是0 ，关注成功，否则不成功
window.location.reload();//刷新页面，不更改样式
} else {
alert(data.msg);//返回提示信息
}
}
);
// $(btn).text("已关注").removeClass("btn-info").addClass("btn-secondary");
} else {
// 取消关注
$.post(
CONTEXT_PATH + "/unfollow",
{"entityType":3,"entityId":$(btn).prev().val()},
function(data) {
data = $.parseJSON(data);
if(data.code == 0) {
window.location.reload();
} else {
alert(data.msg);
}
}
);
//$(btn).text("关注TA").removeClass("btn-secondary").addClass("btn-info");
}
}
注意，关注数量和关注状态此时还没有改变；检验时只能从Redis中查询结果
显示用户主页的关注
在服务层FollowService.java添加方法
public boolean hasFollowed(int userId, int entityType, int entityId) {
String followeeKey = RedisKeyUtil.getFolloweeKey(userId, entityType);
return redisTemplate.opsForZSet().score(followeeKey, entityId) != null;
//查询用户对于该实体的分数，如果有分数，则就是关注了
}
在 UserController.java中添加关注数量，粉丝数量，当前用户是否已关注某个用户
// 个人主页
@RequestMapping(path = "/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);//得到当前用户的关注数量并传递给模板
// 粉丝数量
long followerCount = followService.findFollowerCount(ENTITY_TYPE_USER, userId);
model.addAttribute("followerCount", followerCount);//粉丝的数量传递给模板
// 是否已关注
boolean hasFollowed = false;//当前的登陆用户是否对某用户已经关注
if (hostHolder.getUser() != null) {//当前用户不是空时才有可能关注，所以要做判断
hasFollowed = followService.hasFollowed(hostHolder.getUser().getId(), ENTITY_TYPE_USER, userId);
}
model.addAttribute("hasFollowed", hasFollowed);
return "/site/profile";
}
在Profile.html中调整
<!-- 个人信息 -->
<div class="media mt-5">
<img th:src="${user.headerUrl}" class="align-self-start mr-4 rounded-circle" alt="用户头像" style="width:50px;">
<div class="media-body">
<h5 class="mt-0 text-warning">
<span th:utext="${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>
</div>
</div>
注意判断用户不关注自己，点击某人的详细信息页面时，不显示自己关注自己的情况
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