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第三章：Redis，一站式高性能存储方案

一、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。

二、Spring整合Redis

引入依赖
- spring-boot-starter-data-redis
配置Redis
- 配置数据库参数
- 编写配置类，构造 RedisTemplate
访问Redis
- redisTemplate.opsForValue()
- redisTemplate.opsForHash()
- redisTemplate.opsForList()
- redisTemplate.opsForSet()
- redisTemplate.opsForZSet()

1. config包

在 config 包中创建 RedisConfig 类，代码如下：

@Configuration
public class RedisConfig {

    @Bean
    public 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序列化方式
        template.setHashKeySerializer(RedisSerializer.string());

        // 设置hash的value序列化方式
        template.setHashValueSerializer(RedisSerializer.json());

        template.afterPropertiesSet();;
        return template;
    }
}

2. 修改配置文件

在 application.properties 中添加配置信息：

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

3. 测试类

添加 RedisTests 测试类，各种测试的代码如下：

@SpringBootTest
@ContextConfiguration(classes = CommunityApplication.class)
public class RedisTests {

    @Autowired
    private RedisTemplate redisTemplate;

    @Test
    public void testStrings() {
        String redisKey = "test:count";

        System.out.println("result:");
        redisTemplate.opsForValue().set(redisKey, 1);

        System.out.println(redisTemplate.opsForValue().get(redisKey));
        System.out.println(redisTemplate.opsForValue().increment(redisKey));
        System.out.println(redisTemplate.opsForValue().decrement(redisKey));
    }


    @Test
    public void testHashes() {
        String redisKey = "test:user";

        redisTemplate.opsForHash().put(redisKey, "id", 1);
        redisTemplate.opsForHash().put(redisKey, "username", "zhangsan");

        System.out.println(redisTemplate.opsForHash().get(redisKey, "id"));
        System.out.println(redisTemplate.opsForHash().get(redisKey, "username"));
    }

    @Test
    public void testLists() {
        String redisKey = "test:ids";

        redisTemplate.opsForList().leftPush(redisKey, 101);
        redisTemplate.opsForList().leftPush(redisKey, 102);
        redisTemplate.opsForList().leftPush(redisKey, 103);

        System.out.println(redisTemplate.opsForList().size(redisKey));
        System.out.println(redisTemplate.opsForList().index(redisKey, 0));
        System.out.println(redisTemplate.opsForList().range(redisKey,0, 2));

        System.out.println(redisTemplate.opsForList().leftPop(redisKey));
        System.out.println(redisTemplate.opsForList().leftPop(redisKey));
        System.out.println(redisTemplate.opsForList().leftPop(redisKey));
    }

    @Test
    public void testSet() {
        String redisKey = "test:teacher";

        redisTemplate.opsForSet().add(redisKey,"张三", "李四", "王五", "赵六");

        System.out.println(redisTemplate.opsForSet().size(redisKey));
        System.out.println(redisTemplate.opsForSet().pop(redisKey));
        System.out.println(redisTemplate.opsForSet().members(redisKey));
    }

    @Test
    public void testSortedSet() {
        String redisKey = "test:students";

        redisTemplate.opsForZSet().add(redisKey, "张三", 10);
        redisTemplate.opsForZSet().add(redisKey, "李四", 20);
        redisTemplate.opsForZSet().add(redisKey, "王五", 40);
        redisTemplate.opsForZSet().add(redisKey, "赵六", 30);

        System.out.println(redisTemplate.opsForZSet().zCard(redisKey));
        System.out.println(redisTemplate.opsForZSet().score(redisKey,"张三"));
        System.out.println(redisTemplate.opsForZSet().reverseRank(redisKey,"张三"));
        System.out.println(redisTemplate.opsForZSet().reverseRange(redisKey,0, 2));
    }

    @Test
    public void testKeys() {
        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
    @Test
    public void testBoundOperations() {
        String redisKey = "test:count";
        BoundValueOperations operations = redisTemplate.boundValueOps(redisKey);
        operations.increment();
        operations.increment();
        operations.increment();
        operations.increment();
        operations.increment();
        operations.increment();
        System.out.println(operations.get());
    }

    // 编程式事务
    @Test
    public void testTransactional() {
        Object obj = redisTemplate.execute(new SessionCallback() {
            @Override
            public Object execute(RedisOperations operations) throws DataAccessException {
                String redisKey = "test:tx";

                operations.multi();

                operations.opsForSet().add(redisKey, "aa");
                operations.opsForSet().add(redisKey, "bb");
                operations.opsForSet().add(redisKey, "cc");

                return operations.exec();
            }
        });
        System.out.println(obj);
    }
}

三、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。
详情页面点赞数量
- 统计点赞数量。
- 显示点赞状态。

1. util包

在 util 包下创建 RedisKeyUtil 类，代码如下：

public class RedisKeyUtil {

    public static final String SPLIT = ":";

    private static final String PREFIX_ENTITY_LIKE = "like:entity";

    // 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;
    }
}

2. service包

创建 LikeService 类，代码如下：

@Service
public class LikeService {

    @Autowired
    private 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) {
            redisTemplate.opsForSet().remove(entityLikeKey, userId);
        } else {
            redisTemplate.opsForSet().add(entityLikeKey, userId);
        }
    }

    // 查询某实体点赞的数量
    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;
    }
}

2. controller层

创建 LikeController 层，代码如下：

@Controller
public class LikeController {

    @Autowired
    private LikeService likeService;

    @Autowired
    HostHolder hostHolder;


    @RequestMapping(value = "/like", method = RequestMethod.POST)
    @ResponseBody
    public String like(int entityType, int entityId) {
        User user = hostHolder.getUser();

        // 点赞zzz
        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);
    }
}

在 DiscussPostController 和 HomeController 类中添加查询点赞数量和点赞状态的方法，代码如下：

@Controller
@RequestMapping("/discuss")
public class DiscussPostController implements CommunityConstant {

    @Autowired
    private DiscussPostService discussPostService;

    @Autowired
    private HostHolder hostHolder;

    @Autowired
    private UserService userService;

    @Autowired
    private CommentService commentService;


    @Autowired
    private LikeService likeService;

    @RequestMapping(path = "/add", method = RequestMethod.POST)
    @ResponseBody
    public String addDiscussPost(String title, String content) {
        User user = hostHolder.getUser();
        if (user == null) {
            return CommunityUtil.getJSONString(403,"你还没有登录哦！");
        }

        DiscussPost post = new DiscussPost();
        post.setUserId(user.getId());
        post.setTitle(title);
        post.setContent(content);
        post.setCreateTime(new Date());
        discussPostService.addDiscussPost(post);

        // 报错的情况，会统一处理
        return CommunityUtil.getJSONString(0, "发布成功!");
    }

    @RequestMapping(path = "/detail/{discussPostId}", method = RequestMethod.GET)
    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VO
                Map<String, Object> commentVo = new HashMap<>();
                // 评论
                commentVo.put("comment", comment);
                // 查询到评论的作者
                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);

                // 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";
    }

}

@Controller
public class HomeController implements CommunityConstant {

    @Autowired
    private DiscussPostService discussPostService;

    @Autowired
    private UserService userService;

    @Autowired
    private LikeService likeService;

    @RequestMapping(path = "/index", method = RequestMethod.GET)
    public String getIndexPage(Model model, Page page) {
        // 方法调用时，SpringMVC会自动实例化Model和Page。并将Page注入到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");

        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);

                long likeCount = likeService.findEntityLikeCount(ENTITY_TYPE_POST, post.getId());
                map.put("likeCount", likeCount);

                discussPosts.add(map);

            }
        }

        model.addAttribute("discussPosts", discussPosts);
        return "/index";
    }

    @RequestMapping(path = "/error", method = RequestMethod.GET)
    public String getErrorPage() {
        return "/error/500";

    }
}

4. View层

首页和帖子详情页的代码修改在汇总中进行查看。

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);
            }
        }
    );
}

5. 功能测试

在这里插入图片描述

四、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

1. util包

在 RedisKeyUtil 中添加 getUserLikeKey 方法：

 */
public class RedisKeyUtil {

    public static final String SPLIT = ":";

    private static final String PREFIX_ENTITY_LIKE = "like:entity";

    private static final String PREFIX_USER_LIKE = "like: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;
    }
}

2. servic层

在 LikeService 中对 like 方法进行重载，并且添加 findUserLikeCount 方法，代码如下：

@Service
public class LikeService {

    @Autowired
    private RedisTemplate redisTemplate;

    // 点赞
    public void like(int userId, int entityType, int entityId, int entityUserId) {
        redisTemplate.execute(new SessionCallback() {
            @Override
            public Object execute(RedisOperations operations) throws DataAccessException {
                String entityLikeKey = RedisKeyUtil.getEntityLikeKey(entityType, entityId);
                String userLikeKey = RedisKeyUtil.getUserLikeKey(entityUserId);

                boolean isMember = operations.opsForSet().isMember(entityLikeKey, userId);

                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();
            }
        });
    }


    // 查询某实体点赞的数量
    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;
    }

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

3. controller层

LikeController 类中对 like 方法进行重构，代码如下：

@Controller
public class LikeController {

    @Autowired
    private LikeService likeService;

    @Autowired
    private HostHolder hostHolder;

    @RequestMapping(path = "/like", method = RequestMethod.POST)
    @ResponseBody
    public String like(int entityType, int entityId, int entityUserId) {
        User user = hostHolder.getUser();

        // 点赞
        likeService.like(user.getId(), entityType, entityId, entityUserId);

        // 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);
    }
}

UserController 中添加 getProfilePage 方法，代码如下：

@Controller
@RequestMapping("/user")
public class UserController {

    private static final Logger logger = LoggerFactory.getLogger(AlphaInterceptor.class);

    @Value("${community.path.upload}")
    private String uploadPath;

    @Value("${community.path.domain}")
    private String domain;

    @Value("${server.servlet.context-path}")
    private String contextPath;

    @Autowired
    private UserService userService;

    @Autowired
    private HostHolder hostHolder;

    @Autowired
    private LikeService likeService;

    @LoginRequired
    @RequestMapping(path = "/setting", method = RequestMethod.GET)
    public String getSettingPage() {
        return "/site/setting";
    }

    @LoginRequired
    @RequestMapping(path = "/upload", method = RequestMethod.POST)
    public String uploadHeader(MultipartFile headerImage, Model model) {
        if (headerImage == null) {
            model.addAttribute("error", "您还没有选择图片！");
            return "/site/setting";
        }

        String fileName = headerImage.getOriginalFilename();
        String suffix = fileName.substring(fileName.lastIndexOf("."));
        if (StringUtils.isBlank(suffix)) {
            model.addAttribute("error", "文件的格式不正确!");
            return "/site/setting";
        }

        // 生成随机文件名
        fileName = CommunityUtil.generateUUID() + suffix;
        // 确定文件存放的路径
        File dest = new File(uploadPath + "/" + fileName);
        // 存储文件
        try {
            headerImage.transferTo(dest);
        } catch (IOException e) {
            logger.error("上传文件失败:" + e.getMessage());
            throw new RuntimeException("上传文件失败,服务器发生异常!", e);
        }

        // 更新当前用户头像的路径
        User user = hostHolder.getUser();
        String headerUrl = domain + contextPath + "/user/header/" + fileName;
        userService.updateHeader(user.getId(), headerUrl);


        return "redirect:/index";
    }


    //暴露一个访问接口给外部
    @RequestMapping(path = "/header/{fileName}", method = RequestMethod.GET)
    public void getHeader(@PathVariable("fileName") String fileName, HttpServletResponse response) {
        // 服务器存放路径
        fileName = uploadPath + "/" + fileName;
        // 文件后缀
        String suffix = fileName.substring(fileName.lastIndexOf("."));
        // 响应图片
        response.setContentType("image/" + suffix);
        try (
                FileInputStream fis = new FileInputStream(fileName);
                OutputStream os = response.getOutputStream();
        ) {
            byte[] buffer = new byte[1024];
            int b = 0;
            while ((b = fis.read(buffer)) != -1) {
                os.write(buffer, 0, b);
            }
        } catch (IOException e) {
            logger.error("读取头像失败: " + e.getMessage());
        }
    }

    // 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);

        return "/site/profile";
    }
}

4. View层

首页、帖子详情页和个人主页的代码修改在汇总中进行查看。
discuss-detail.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);
            }
        }
    );
}

5. 功能测试

在这里插入图片描述

查看 redis 数据库：

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仿牛客社区项目（第四章）（上）

第三章：Redis，一站式高性能存储方案

一、Redis入门

二、Spring整合Redis

1. config包

2. 修改配置文件

3. 测试类

三、点赞

1. util包

2. service包

2. controller层

4. View层

5. 功能测试

四、我收到的赞

1. util包

2. servic层

3. controller层

4. View层

5. 功能测试

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仿牛客社区项目（第四章）（上）

第三章：Redis，一站式高性能存储方案

一、Redis入门

二、Spring整合Redis

1. config包

2. 修改配置文件

3. 测试类

三、点赞

1. util包

2. service包

2. controller层

4. View层

5. 功能测试

四、我收到的赞

1. util包

2. servic层

3. controller层

4. View层

5. 功能测试

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