1. Redis入门

Redis是一款基于键值对的NoSQL数据库，它的值支持多种数据结构：字符串(strings)、哈希(hashes)、列表(lists)、集合(sets)、有序集合(sorted sets)等。
Redis将所有的数据都存放在内存中，所以它的读写性能十分惊人。同时，Redis还可以将内存中的数据以快照或日志的形式保存到硬盘上，以保证数据的安全性。
Redis典型的应用场景包括：缓存、排行榜、计数器、社交网络、消息队列等

https://redis.io
https://github.com/microsoftarchive/redis

安装Redis

双击 “Redis-x64-3.2.100.msi”，将安装目录配到环境变量中，打开 cmd，输入 redis-cli，连接 Redis：

String 类型的存取

127.0.0.1:6379> set test:count 1
OK
127.0.0.1:6379> get test:count
"1"
127.0.0.1:6379> incr test:count
(integer) 2
127.0.0.1:6379> decr test:count
(integer) 1

哈希类型的存取

127.0.0.1:6379> hset test:user id 1
(integer) 1
127.0.0.1:6379> hset test:user username zhangsan
(integer) 1
127.0.0.1:6379> hget test:user id
"1"
127.0.0.1:6379> hget test:user username
"zhangsan"

list类型的存取

127.0.0.1:6379> lpush test:ids 101 102 103
(integer) 3
127.0.0.1:6379> llen test:ids
(integer) 3
127.0.0.1:6379> lindex test:ids 0
"103"
127.0.0.1:6379> lindex test:ids 2
"101"
127.0.0.1:6379> lrange test:ids 0 2
1) "103"
2) "102"
3) "101"
127.0.0.1:6379> rpop test:ids
"101"

集合类型的存取
无序
scard 统计集合内的元素数
spop 随机弹出一个元素
smembers 查看集合剩余元素

127.0.0.1:6379> sadd test:teachers aaa bbb ccc ddd eee
(integer) 5
127.0.0.1:6379> scard test:teachers
(integer) 5
127.0.0.1:6379> spop test:teachers
"eee"
127.0.0.1:6379> smembers test:teachers
1) "aaa"
2) "ddd"
3) "bbb"
4) "ccc"

有序
zscore 查看某个元素的分数
zrank 查看某个元素的排名

127.0.0.1:6379> zadd test:students 10 aaa 20 bbb 30 ccc 40 ddd 50 eee
(integer) 5
127.0.0.1:6379> zcard test:students
(integer) 5
127.0.0.1:6379> zscore test:students ccc
"30"
127.0.0.1:6379> zrank test:students ccc
(integer) 2
127.0.0.1:6379> zrange test:students 0 2
1) "aaa"
2) "bbb"
3) "ccc"

全局命令
对所有的数据类型都生效

查看库中所有的 key

127.0.0.1:6379> keys *
1) "test:ids"
2) "test:user"
3) "test:students"
4) "test:teachers"
5) "test:count"

所有以 test 开头的 key

127.0.0.1:6379> keys test*
1) "test:ids"
2) "test:user"
3) "test:students"
4) "test:teachers"
5) "test:count"

查看某个 key 的类型

127.0.0.1:6379> type test:user
hash

查看某个 key 是否存在，1表示存在

127.0.0.1:6379> exists test:user
(integer) 1

删掉某个 key

127.0.0.1:6379> del test:user
(integer) 1
127.0.0.1:6379> exists test:user
(integer) 0

设置某个 key 的过期时间 (秒)

127.0.0.1:6379> expire test:stundets 10
(integer) 0

10秒之后查看 test:stundets，不存在了

127.0.0.1:6379> exists test:stundets
(integer) 0

2. SpringBoot整合Redis

pom.xml
版本已经在父 pom 中指定了，所以可以不写

<dependency><groupId>org.springframework.boot</groupId><artifactId>spring-boot-starter-data-redis</artifactId>
</dependency>

application.properties

# redis
spring.redis.database=11
spring.redis.host=localhost
spring.redis.port=6379

配置类

package com.nowcoder.community.Config;import org.springframework.context.annotation.Bean;
import org.springframework.context.annotation.Configuration;
import org.springframework.data.redis.connection.RedisConnectionFactory;
import org.springframework.data.redis.core.RedisTemplate;
import org.springframework.data.redis.serializer.RedisSerializer;@Configuration
public class RedisConfig {@Beanpublic RedisTemplate<String, Object> redisTemplate(RedisConnectionFactory factory) {RedisTemplate<String, Object> template = new RedisTemplate<>();template.setConnectionFactory(factory);// 设置key的序列化方式template.setKeySerializer(RedisSerializer.string());// 设置value的序列化方式template.setValueSerializer(RedisSerializer.json());// 设置hash的key的序列化方式template.setHashKeySerializer(RedisSerializer.string());// 设置hash的value的序列化方式template.setHashValueSerializer(RedisSerializer.json());template.afterPropertiesSet();return template;}
}

测试一下
创新的测试类

package com.nowcoder.community;import org.junit.jupiter.api.Test;
import org.springframework.boot.test.context.SpringBootTest;
import org.springframework.dao.DataAccessException;
import org.springframework.data.redis.core.BoundValueOperations;
import org.springframework.data.redis.core.RedisOperations;
import org.springframework.data.redis.core.RedisTemplate;
import org.springframework.data.redis.core.SessionCallback;import javax.annotation.Resource;
import java.util.concurrent.TimeUnit;@SpringBootTest
public class RedisTests {@Resourceprivate RedisTemplate redisTemplate;@Testpublic void testStrings() {String redisKey = "test:count";redisTemplate.opsForValue().set(redisKey, 1);System.out.println(redisTemplate.opsForValue().get(redisKey));//取值System.out.println(redisTemplate.opsForValue().increment(redisKey));//增加System.out.println(redisTemplate.opsForValue().decrement(redisKey));//减少}@Testpublic void testHashes() {String redisKey = "test:user";redisTemplate.opsForHash().put(redisKey, "id", 1);redisTemplate.opsForHash().put(redisKey, "username", "张三");//取值System.out.println(redisTemplate.opsForHash().get(redisKey, "id"));System.out.println(redisTemplate.opsForHash().get(redisKey, "username"));}@Testpublic void testLists() {String redisKey = "test:ids";redisTemplate.opsForList().leftPush(redisKey, 101);redisTemplate.opsForList().leftPush(redisKey, 102);redisTemplate.opsForList().leftPush(redisKey, 103);//取值System.out.println(redisTemplate.opsForList().size(redisKey));System.out.println(redisTemplate.opsForList().index(redisKey, 0));//左边下标0的数据System.out.println(redisTemplate.opsForList().range(redisKey, 0, 2));//左边[0,2]的数据System.out.println(redisTemplate.opsForList().leftPop(redisKey));//从左边弹出System.out.println(redisTemplate.opsForList().leftPop(redisKey));System.out.println(redisTemplate.opsForList().leftPop(redisKey));}@Testpublic void testSets() {String redisKey = "test:teachers";redisTemplate.opsForSet().add(redisKey, "刘备", "关羽", "张飞");//取值System.out.println(redisTemplate.opsForSet().size(redisKey));System.out.println(redisTemplate.opsForSet().pop(redisKey));//随机弹出一个System.out.println(redisTemplate.opsForSet().members(redisKey));//剩余元素}@Testpublic void testSortedSets() {String redisKey = "test:students";redisTemplate.opsForZSet().add(redisKey, "唐僧", 80);//80是唐僧的分数redisTemplate.opsForZSet().add(redisKey, "悟空", 90);redisTemplate.opsForZSet().add(redisKey, "沙僧", 50);redisTemplate.opsForZSet().add(redisKey, "八戒", 60);System.out.println(redisTemplate.opsForZSet().zCard(redisKey));//统计元素个数System.out.println(redisTemplate.opsForZSet().score(redisKey, "八戒"));//统计某个元素的分数//统计某个元素的排名，默认由小到大System.out.println(redisTemplate.opsForZSet().rank(redisKey, "八戒"));//由大到小System.out.println(redisTemplate.opsForZSet().reverseRank(redisKey, "八戒"));//最小的前三名（默认由小到大排）System.out.println(redisTemplate.opsForZSet().range(redisKey, 0, 2));//最大的前三名System.out.println(redisTemplate.opsForZSet().reverseRange(redisKey, 0, 2));}@Testpublic void testKeys() { //测试全局命令redisTemplate.delete("test:user");System.out.println(redisTemplate.hasKey("test:user"));redisTemplate.expire("test:students", 10, TimeUnit.SECONDS);}//多次访问同一个key，使用绑定，简化代码@Testpublic void testBoundOperations() {String redisKey = "test:count";BoundValueOperations operations = redisTemplate.boundValueOps(redisKey);operations.increment();operations.increment();operations.increment();System.out.println(operations.get());}//编程式事务@Testpublic void testTransactional() {Object obj = redisTemplate.execute(new SessionCallback() {@Overridepublic Object execute(RedisOperations operations) throws DataAccessException {String redisKey = "test:tx";operations.multi();//启动事务operations.opsForSet().add(redisKey, "张三");operations.opsForSet().add(redisKey, "李四");operations.opsForSet().add(redisKey, "王五");//没有数据，因为此时还未执行addSystem.out.println(operations.opsForSet().members(redisKey));return operations.exec();//提交事务}});System.out.println(obj);}
}

3. 点赞

点赞
- 支持对帖子、评论点赞。
- 第1次点赞，第2次取消点赞。
首页点赞数量
- 统计帖子的点赞数量。
详情页点赞数量
- 统计点赞数量。
- 显示点赞状态。

因为点赞是频率非常高的操作，所以把点赞数据存到 Redis 中提高性能

写个工具类

package com.nowcoder.community.util;public class RedisKeyUtil {public static final String SPLIT = ":";public static final String PREFIX_ENTITY_LIKE = "like:entity";//某个实体(帖子、评论)的赞//like:entity:entityType:entityId-->set(userId)public static String getEntityLikeKey(int entityType, int entityId) {return PREFIX_ENTITY_LIKE + SPLIT + entityType + SPLIT + entityId;}}

service

package com.nowcoder.community.service;import com.nowcoder.community.util.RedisKeyUtil;
import org.springframework.data.redis.core.RedisTemplate;
import org.springframework.stereotype.Service;import javax.annotation.Resource;@Service
public class LikeService {@Resourceprivate RedisTemplate redisTemplate;// 点赞public void like(int userId, int entityType, int entityId) {String entityLikeKey = RedisKeyUtil.getEntityLikeKey(entityType, entityId);Boolean isMember = redisTemplate.opsForSet().isMember(entityLikeKey, userId);if (isMember) { //点过赞了，则取消redisTemplate.opsForSet().remove(entityLikeKey, userId);} else {redisTemplate.opsForSet().add(entityLikeKey, userId);}}//查询某实体赞的数量public long findEntityLikeCount(int entityType, int entityId) {String entityLikeKey = RedisKeyUtil.getEntityLikeKey(entityType, entityId);return redisTemplate.opsForSet().size(entityLikeKey);}// 查询某人对某实体的点赞状态public int findEntityLikeStatus(int userId, int entityType, int entityId) {String entityLikeKey = RedisKeyUtil.getEntityLikeKey(entityType, entityId);return redisTemplate.opsForSet().isMember(entityLikeKey, userId) ? 1 : 0;}
}

controller

package com.nowcoder.community.controller;import com.nowcoder.community.entity.User;
import com.nowcoder.community.service.LikeService;
import com.nowcoder.community.util.CommunityUtil;
import com.nowcoder.community.util.HostHolder;
import org.springframework.stereotype.Controller;
import org.springframework.web.bind.annotation.PostMapping;
import org.springframework.web.bind.annotation.ResponseBody;import javax.annotation.Resource;
import java.util.HashMap;
import java.util.Map;@Controller
public class LikeController {@Resourceprivate LikeService likeService;@Resourceprivate HostHolder hostHolder;@PostMapping("/like")@ResponseBodypublic String like(int entityType, int entityId) {User user = hostHolder.getUser();// 点赞likeService.like(user.getId(), entityType, entityId);// 数量long likeCount = likeService.findEntityLikeCount(entityType, entityId);// 状态int likeStatus = likeService.findEntityLikeStatus(user.getId(), entityType, entityId);// 返回的结果Map<String, Object> map = new HashMap<>();map.put("likeCount", likeCount);map.put("likeStatus", likeStatus);return CommunityUtil.getJSONString(0, null, map);}
}

discuss-detail.html
86行

<li class="d-inline ml-2"><a href="javascript:;" th:onclick="|like(this, 1, ${post.id});|" class="text-primary"><b>赞</b> <i>11</i></a>
</li>

138行

<li class="d-inline ml-2"><a href="javascript:;" th:onclick="|like(this, 2, ${cvo.comment.id})|" class="text-primary"><b>赞</b>(<i>1</i>)</a>
</li>

164行

<li class="d-inline ml-2"><a href="javascript:;" th:onclick="|like(this, 2, ${rvo.reply.id})|" class="text-primary"><b>赞</b>(<i>1</i>)</a>
</li>

在最后面加一个 script 标签

<script th:src="@{/js/discuss.js}"></script>

resources / static / js 下新建 discuss.js

function like(btn, entityType, entityId) {$.post(CONTEXT_PATH + "/like",{"entityType":entityType, "entityId":entityId},function (data) {data = $.parseJSON(data);if (data.code == 0) {$(btn).children("i").text(data.likeCount);$(btn).children("b").text(data.likeStatus==1?'已赞':'赞');} else {alert(data.msg);}});
}

启动，测试：登陆之后找个帖子点赞试试。再点一下赞，取消了，然后对评论以及评论的回复点赞试试

修改初始时赞的数量不对的问题：

1.处理首页

完善 HomeController 的 getIndexPage() 方法

public class HomeController implements CommunityConstant { //为了使用常量@Resourceprivate LikeService likeService;@GetMapping("/index")public String getIndexPage(Model model, Page page) {//方法调用前, SpringMVC会自动实例化Model和Page,并将Page注入Model.// 所以,在thymeleaf中可以直接访问Page对象中的数据.page.setRows(discussPostService.findDiscussPostRows(0));page.setPath("/index");//这个list里的帖子含有外键userId，我们需要查到userName拼接到帖子上List<DiscussPost> list = discussPostService.findDiscussPosts(0, page.getOffset(), page.getLimit());List<Map<String, Object>> discussPosts = new ArrayList<>();if (list != null) {for (DiscussPost post : list) {Map<String, Object> map = new HashMap<>();map.put("post", post);User user = userService.findUserById(post.getUserId());map.put("user", user);//加了这两句long likeCount = likeService.findEntityLikeCount(ENTITY_TYPE_POST, post.getId());map.put("likeCount", likeCount);discussPosts.add(map);}}model.addAttribute("discussPosts", discussPosts);return "/index";}

index.html
134行

<li class="d-inline ml-2">赞 <span th:text="${map.likeCount}">11</span></li>

2.处理帖子详情页

DiscussPostController 的 getDiscussPost() 方法

 @Resourceprivate LikeService likeService;@GetMapping("/detail/{discussPostId}")public String getDiscussPost(@PathVariable("discussPostId") int discussPostId, Model model, Page page) {//帖子DiscussPost post = discussPostService.findDiscussPostById(discussPostId);model.addAttribute("post", post);//作者User user = userService.findUserById(post.getUserId());model.addAttribute("user", user);// 点赞数量long likeCount = likeService.findEntityLikeCount(ENTITY_TYPE_POST, discussPostId);model.addAttribute("likeCount", likeCount);// 点赞状态int likeStatus = hostHolder.getUser() == null ? 0 :likeService.findEntityLikeStatus(hostHolder.getUser().getId(), ENTITY_TYPE_POST, discussPostId);model.addAttribute("likeStatus", likeStatus);//评论的分页信息page.setLimit(5);page.setPath("/discuss/detail/" + discussPostId);page.setRows(post.getCommentCount());//评论：给帖子的评论//回复：给评论的评论//评论列表List<Comment> commentList = commentService.findCommentsByEntity(ENTITY_TYPE_POST, post.getId(), page.getOffset(), page.getLimit());//评论VO列表List<Map<String, Object>> commentVoList = new ArrayList<>();if (commentList != null) {for (Comment comment : commentList) {//评论VOMap<String, Object> commentVo = new HashMap<>();//往VO中添加评论commentVo.put("comment", comment);//添加作者commentVo.put("user", userService.findUserById(comment.getUserId()));// 点赞数量likeCount = likeService.findEntityLikeCount(ENTITY_TYPE_COMMENT, comment.getId());commentVo.put("likeCount", likeCount);// 点赞状态likeStatus = hostHolder.getUser() == null ? 0 :likeService.findEntityLikeStatus(hostHolder.getUser().getId(), ENTITY_TYPE_COMMENT, comment.getId());commentVo.put("likeStatus", likeStatus);//查询回复列表List<Comment> replyList = commentService.findCommentsByEntity(ENTITY_TYPE_COMMENT, comment.getId(), 0, Integer.MAX_VALUE);//回复VO列表List<Map<String, Object>> replyVoList = new ArrayList<>();if (replyList != null) {for (Comment reply : replyList) {Map<String, Object> replyVo = new HashMap<>();//回复replyVo.put("reply", reply);//作者replyVo.put("user", userService.findUserById(reply.getUserId()));//回复的目标User target = reply.getTargetId() == 0 ? null : userService.findUserById(reply.getTargetId());replyVo.put("target", target);// 点赞数量likeCount = likeService.findEntityLikeCount(ENTITY_TYPE_COMMENT, reply.getId());replyVo.put("likeCount", likeCount);// 点赞状态likeStatus = hostHolder.getUser() == null ? 0 :likeService.findEntityLikeStatus(hostHolder.getUser().getId(), ENTITY_TYPE_COMMENT, reply.getId());replyVo.put("likeStatus", likeStatus);replyVoList.add(replyVo);}}commentVo.put("replys", replyVoList);//回复的数量int replyCount = commentService.findCommentCount(ENTITY_TYPE_COMMENT, comment.getId());commentVo.put("replyCount", replyCount);commentVoList.add(commentVo);}}model.addAttribute("comments", commentVoList);return "site/discuss-detail";}

discuss-detail.html
88行

<b th:text="${likeStatus==1?'已赞':'赞'}">赞</b> <i th:text="${likeCount}">11</i>

140行

<b th:text="${cvo.likeStatus==1?'已赞':'赞'}">赞</b>(<i th:text="${cvo.likeCount}">1</i>)

166行

<b th:text="${rvo.likeStatus==1?'已赞':'赞'}">赞</b>(<i th:text="${rvo.likeCount}">1</i>)

4. 我收到的赞

重构点赞功能

以用户为key，记录点赞数量
increment(key)，decrement(key)

开发个人主页

以用户为key，查询点赞数量

RedisKeyUtil 增加属性和方法

public static final String PREFIX_USER_LIKE = "like:user";// 某个用户的赞
// like:user:userId -> int
public static String getUserLikeKey(int userId) {return PREFIX_USER_LIKE + SPLIT + userId;
}

LikeService
重构 like() 方法

// 点赞
public void like(int userId, int entityType, int entityId, int entityUserId) {redisTemplate.execute(new SessionCallback() {@Overridepublic Object execute(RedisOperations operations) throws DataAccessException {String entityLikeKey = RedisKeyUtil.getEntityLikeKey(entityType, entityId);String userLikeKey = RedisKeyUtil.getUserLikeKey(entityUserId);//这句查询不能放在事务内部boolean isMember = operations.opsForSet().isMember(entityLikeKey, userId);//开启事务operations.multi();if (isMember) {operations.opsForSet().remove(entityLikeKey, userId);operations.opsForValue().decrement(userLikeKey);} else {operations.opsForSet().add(entityLikeKey, userId);operations.opsForValue().increment(userLikeKey);}return operations.exec();}});
}

增加一个方法，统计赞的数量

// 查询某个用户获得的赞的数量
public int findUserLikeCount(int userId) {String userLikeKey = RedisKeyUtil.getUserLikeKey(userId);Integer count = (Integer) redisTemplate.opsForValue().get(userLikeKey);return count == null ? 0 : count.intValue();
}

LikeController
like() 方法增加一个形参 entityUserId

public String like(int entityType, int entityId, int entityUserId) {...// 点赞likeService.like(user.getId(), entityType, entityId, entityUserId);

discuss-detail.html
78行

<a th:href="@{|/user/profile/${user.id}|}">

87行

<a href="javascript:;" th:onclick="|like(this, 1, ${post.id}, ${post.userId});|" class="text-primary">

139行

<a href="javascript:;" th:onclick="|like(this, 2, ${cvo.comment.id},${cvo.comment.userId})|" class="text-primary">

165行

<a href="javascript:;" th:onclick="|like(this, 2, ${rvo.reply.id}, ${rvo.reply.userId})|" class="text-primary">

discuss.js

function like(btn, entityType, entityId, entityUserId) {$.post(CONTEXT_PATH + "/like",{"entityType":entityType, "entityId":entityId, "entityUserId":entityUserId},function (data) {data = $.parseJSON(data);if (data.code == 0) {$(btn).children("i").text(data.likeCount);$(btn).children("b").text(data.likeStatus==1?'已赞':'赞');} else {alert(data.msg);}});
}

UserController

@Resource
private LikeService likeService;//个人主页
@GetMapping("/profile/{userId}")
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);// 获赞数量int likeCount = likeService.findUserLikeCount(userId);model.addAttribute("likeCount", likeCount);return "/site/profile";
}

index.html
43行

<a class="dropdown-item text-center" th:href="@{|/user/profile/${loginUser.id}|}">个人主页</a>

122行

<a th:href="@{|/user/profile/${map.user.id}|}">

profile.html
2行

<html lang="en" xmlns:th="http://www.thymeleaf.org">

8行

<link rel="stylesheet" th:href="@{/css/global.css}" />

14行

<!-- 头部 -->
<header class="bg-dark sticky-top" th:replace="index::header">

165-166行

<script th:src="@{/js/global.js}"></script>
<script th:src="@{/js/profile.js}"></script>

80行

<img th:src="${user.headerUrl}" class="align-self-start mr-4 rounded-circle" alt="用户头像" style="width:50px;">

83行

<span th:utext="${user.username}">nowcoder</span>

87行

<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>

92行

<span class="ml-4">获得了 <i class="text-danger" th:text="${likeCount}">87</i> 个赞</span>

启动测试，先删掉之前的点赞数据

C:\Users\15642>redis-cli
127.0.0.1:6379> select 11
OK
127.0.0.1:6379[11]> keys *
1) "like:entity:2:94"
2) "like:entity:1:234"
3) "test:teachers"
4) "test:tx"
5) "test:count"
127.0.0.1:6379[11]> flushdb
OK
127.0.0.1:6379[11]> keys *
(empty list or set)

登陆之后，随便选个人的帖子进行点赞，再给他的评论点赞，然后去他的主页看看收到的赞的数量对不对

5. 关注、取消关注

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。

RedisKeyUtil
增加属性和方法

public static final String PREFIX_FOLLOWEE = "followee";
public static final String PREFIX_FOLLOWER = "follower";//某个用户关注的实体
//followee:userId:entityType -> zSet(entityId, now)
public static String getFolloweeKey(int userId, int entityType) {return PREFIX_FOLLOWEE + SPLIT + userId + SPLIT + entityType;
}//某个用户拥有的粉丝
//follower:entityType:entityId -> zSet(userId, now)
public static String getFollowerKey(int entityType, int entityId) {return PREFIX_FOLLOWER + SPLIT + entityType + SPLIT + entityId;
}

新建 FollowService

package com.nowcoder.community.service;import com.nowcoder.community.util.RedisKeyUtil;
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 javax.annotation.Resource;@Service
public class FollowService {@Resourceprivate RedisTemplate redisTemplate;//关注public void follow(int userId, int entityType, int entityId) {redisTemplate.execute(new SessionCallback() {@Overridepublic Object execute(RedisOperations operations) throws DataAccessException {String followeeKey = RedisKeyUtil.getFolloweeKey(userId, entityType);String followerKey = RedisKeyUtil.getFollowerKey(entityType, entityId);operations.multi();operations.opsForZSet().add(followeeKey, entityId, System.currentTimeMillis());operations.opsForZSet().add(followerKey, userId, System.currentTimeMillis());return operations.exec();}});}//取消关注public void unfollow(int userId, int entityType, int entityId) {redisTemplate.execute(new SessionCallback() {@Overridepublic 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);operations.opsForZSet().remove(followerKey, userId);return operations.exec();}});}
}

新建 FollowController

package com.nowcoder.community.controller;import com.nowcoder.community.entity.User;
import com.nowcoder.community.service.FollowService;
import com.nowcoder.community.util.CommunityUtil;
import com.nowcoder.community.util.HostHolder;
import org.springframework.stereotype.Controller;
import org.springframework.web.bind.annotation.PostMapping;
import org.springframework.web.bind.annotation.ResponseBody;import javax.annotation.Resource;@Controller
public class FollowController {@Resourceprivate FollowService followService;@Resourceprivate HostHolder hostHolder;@PostMapping("/follow")@ResponseBodypublic String follow(int entityType, int entityId) {User user = hostHolder.getUser();followService.follow(user.getId(), entityType, entityId);return CommunityUtil.getJSONString(0, "已关注！");}@PostMapping("/unfollow")@ResponseBodypublic 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！");}
}

CommunityConstant

//实体类型：用户
int ENTITY_TYPE_USER = 3;

profile.html
84行 “关注TA” 的上一行加上：

<input type="hidden" id="entityId" th:value="${user.id}">

修改后的 profile.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);}});// $(btn).text("已关注").removeClass("btn-info").addClass("btn-secondary");} else {// 取消关注$.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");}
}

FollowService
增加方法

// 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;
}

UserController
完善 getProfilePage 方法

public class UserController implements CommunityConstant {@Resourceprivate FollowService followService;//个人主页@GetMapping("/profile/{userId}")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);// 获赞数量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 = false;if (hostHolder.getUser() != null) {hasFollowed = followService.hasFollowed(hostHolder.getUser().getId(), ENTITY_TYPE_USER, userId);}model.addAttribute("hasFollowed", hasFollowed);return "/site/profile";}

profile.html
91行

<span>关注了 <a class="text-primary" href="followee.html" th:text="${followeeCount}">5</a> 人</span>

92行

<span class="ml-4">关注者 <a class="text-primary" href="follower.html" th:text="${followerCount}">123</a> 人</span>

85行

<button type="button" class="btn 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>

启动，测试

6. 关注列表、粉丝列表

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。

FollowService
增加方法

public class FollowService implements CommunityConstant {@Resourceprivate UserService userService;// 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;}

FollowController
增加方法

public class FollowController implements CommunityConstant {@Resourceprivate UserService userService;@GetMapping("/followees/{userId}")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";}@GetMapping("/followers/{userId}")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);}

profile.html
92行

<span>关注了 <a class="text-primary" th:href="@{|/followees/${user.id}|}" th:text="${followeeCount}">5</a> 人</span>

93行

<span class="ml-4">关注者 <a class="text-primary" th:href="@{|/followers/${user.id}|}" th:text="${followerCount}">123</a> 人</span>

followee.html
2行

<html lang="en" xmlns:th="http://www.thymeleaf.org">

8行

<link rel="stylesheet" th:href="@{/css/global.css}" />

14行

<!-- 头部 -->
<header class="bg-dark sticky-top" th:replace="index::header">

233-234行

<script th:src="@{/js/global.js}"></script>
<script th:src="@{/js/profile.js}"></script>

删掉93-148行，只留一个 li 标签即可

64行的 div 标签

<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&gt;</a>
</div>

83行

<li class="media pb-3 pt-3 mb-3 border-bottom position-relative" th:each="map:${users}">

84行 a 标签

<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>

89行

<span class="text-success" th:utext="${map.user.username}">落基山脉下的闲人</span>

90行 span 标签

<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>

101行

<!-- 分页 -->
<nav class="mt-5" th:replace="index::pagination">

95行前面加一行

<input type="hidden" id="entityId" th:value="${map.user.id}">

96行 button 标签

<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>

follower.html 做一模一样的处理！

启动，测试，登录一个账号，随便关注一个人，再登录那个人的账号，查看是否粉丝+1

7. 优化登录模块

使用Redis存储验证码

验证码需要频繁的访问与刷新，对性能要求较高。
验证码不需永久保存，通常在很短的时间后就会失效。
分布式部署时，存在Session共享的问题。

使用Redis存储登录凭证

处理每次请求时，都要查询用户的登录凭证，访问的频率非常高。

使用Redis缓存用户信息

处理每次请求时，都要根据凭证查询用户信息，访问的频率非常高。

7.1 使用Redis存储验证码

RedisKeyUtil
增加属性和方法

public static final String PREFIX_KAPTCHA = "kaptcha";// 登录验证码的key
public static String getKaptchaKey(String owner) {return PREFIX_KAPTCHA + SPLIT + owner;
}

LoginController
重构 getKaptcha() 方法、login() 方法

@Resource
private RedisTemplate redisTemplate;@GetMapping("/kaptcha")
public void getKaptcha(HttpServletResponse response) {//生成验证码String text = kaptchaProducer.createText();BufferedImage image = kaptchaProducer.createImage(text);//验证的归属String kaptchaOwner = CommunityUtil.generateUUID();Cookie cookie = new Cookie("kaptchaOwner", kaptchaOwner);cookie.setMaxAge(60);cookie.setPath(contextPath);response.addCookie(cookie);//将验证码存入 RedisString redisKey = RedisKeyUtil.getKaptchaKey(kaptchaOwner);redisTemplate.opsForValue().set(redisKey, text, 60, TimeUnit.SECONDS);//将图片输出给浏览器response.setContentType("image/png");try {OutputStream os = response.getOutputStream();ImageIO.write(image, "png", os);} catch (IOException e) {logger.error("响应验证码失败:" + e.getMessage());}
}@PostMapping("/login")
public String login(String username, String password, String code,boolean rememberme, Model model, HttpServletResponse response,@CookieValue("kaptchaOwner") String kaptchaOwner) {//检查验证码String kaptcha = null;if (StringUtils.isNotBlank(kaptchaOwner)) {String redisKey = RedisKeyUtil.getKaptchaKey(kaptchaOwner);kaptcha = (String) redisTemplate.opsForValue().get(redisKey);}//后面的不变if (StringUtils.isBlank(kaptcha) || StringUtils.isBlank(code) || !kaptcha.equalsIgnoreCase(code)) {model.addAttribute("codeMsg", "验证码不正确！");return "/site/login";}//检查账号、密码int expiredSeconds = rememberme ?  REMEMBER_EXPIRED_SECONDS : DEFAULT_EXPIRED_SECONDS;Map<String, Object> map = userService.login(username, password, expiredSeconds);if (map.containsKey("ticket")) {//只有登陆成功才会存ticketCookie cookie = new Cookie("ticket", map.get("ticket").toString());cookie.setPath(contextPath);cookie.setMaxAge(expiredSeconds);response.addCookie(cookie);return "redirect:/index";} else {model.addAttribute("usernameMsg", map.get("usernameMsg"));model.addAttribute("passwordMsg", map.get("passwordMsg"));return "/site/login";}
}

7.2 使用Redis存储登录凭证

RedisKeyUtil

public static final String PREFIX_TICKET = "ticket";// 登录凭证
public static String getTicketKey(String ticket) {return PREFIX_TICKET + SPLIT + ticket;
}

LoginTicketMapper 可以废弃掉了，在类上加上注解 @Deprecated

UserService

// @Resource
// private LoginTicketMapper loginTicketMapper;@Resource
private RedisTemplate redisTemplate;

修改 login() 方法的后半段

//生成登录凭证
LoginTicket loginTicket = new LoginTicket();
loginTicket.setUserId(user.getId());
loginTicket.setTicket(CommunityUtil.generateUUID());
loginTicket.setStatus(0);
loginTicket.setExpired(new Date(System.currentTimeMillis() + expiredSeconds * 1000));
// loginTicketMapper.insertLoginTicket(loginTicket);String redisKey = RedisKeyUtil.getTicketKey(loginTicket.getTicket());
redisTemplate.opsForValue().set(redisKey, loginTicket);map.put("ticket", loginTicket.getTicket());
return map;

logout() 方法

public void logout(String ticket) {// loginTicketMapper.updateStatus(ticket, 1);String redisKey = RedisKeyUtil.getTicketKey(ticket);LoginTicket loginTicket = (LoginTicket) redisTemplate.opsForValue().get(redisKey);loginTicket.setStatus(1);//状态为1，表示删除redisTemplate.opsForValue().set(redisKey, loginTicket);
}

findLoginTicket() 方法

public LoginTicket findLoginTicket(String ticket) {//  return loginTicketMapper.selectByTicket(ticket);String redisKey = RedisKeyUtil.getTicketKey(ticket);return (LoginTicket) redisTemplate.opsForValue().get(redisKey);
}

7.3 使用Redis缓存用户信息

RedisKeyUtil

public static final String PREFIX_USER = "user";// 用户
public static String getUserKey(int userId) {return PREFIX_USER + SPLIT + userId;
}

UserService
增加三个方法

// 1.优先从缓存中取值
private User getCache(int userId) {String redisKey = RedisKeyUtil.getUserKey(userId);return (User) redisTemplate.opsForValue().get(redisKey);
}// 2.取不到时初始化缓存数据
private User initCache(int userId) {User user = userMapper.selectById(userId);String redisKey = RedisKeyUtil.getUserKey(userId);redisTemplate.opsForValue().set(redisKey, user, 3600, TimeUnit.SECONDS);return user;
}
// 3.数据变更时清除缓存数据
private void clearCache(int userId) {String redisKey = RedisKeyUtil.getUserKey(userId);redisTemplate.delete(redisKey);
}

修改 findUserById() 方法

public User findUserById(int id) {//  return userMapper.selectById(id);User user = getCache(id);if (user == null) {user = initCache(id);}return user;
}

修改 activation() 方法

public int activation(int userId, String code) {User user = userMapper.selectById(userId);if (user.getStatus() == 1) {return ACTIVATION_REPEAT;} else if (user.getActivationCode().equals(code)) {userMapper.updateStatus(userId, 1);clearCache(userId);return ACTIVATION_SUCCESS;} else {return ACTIVATION_FAILURE;}
}

修改 updateHeader() 方法

public int updateHeader(int userId, String headerUrl) {int rows = userMapper.updateHeader(userId, headerUrl);clearCache(userId);return rows;
}

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目录