第二章 开发社区核心功能（一）

包含敏感词的文件：sensitive-words.txt

赌博
嫖娼
吸毒
开票

敏感词过滤器：SensitiveFilter.java

/**
 * 敏感词过滤器
 *
 * @author xiexu
 * @create 2022-06-04 17:12
 */
@Component
public class SensitiveFilter {

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

    // 敏感词替换符
    private static final String REPLACEMENT = "***";

    // 根节点
    private TrieNode rootNode = new TrieNode();

    // 前缀树
    private class TrieNode {
        // 关键词结束标识
        private boolean isKeyWordEnd = false;

        // 当前节点的子节点(key是下级字符，value是下级节点)
        private Map<Character, TrieNode> subNodes = new HashMap<>();

        public boolean isKeyWordEnd() {
            return isKeyWordEnd;
        }

        public void setKeyWordEnd(boolean keyWordEnd) {
            isKeyWordEnd = keyWordEnd;
        }

        // 添加子节点的方法
        public void addSubNode(Character c, TrieNode node) {
            subNodes.put(c, node);
        }

        // 获取子节点
        public TrieNode getSubNode(Character c) {
            return subNodes.get(c);
        }
    }

    @PostConstruct // 表示这是一个初始化方法，在初始化当前类以后会调用该方法，而当前类在服务一启动的时候就会被初始化
    public void init() {
        InputStream is = null;
        BufferedReader reader = null;
        try {
            // 通过类加载器获取该敏感词文件
            is = this.getClass().getClassLoader().getResourceAsStream("sensitive-words.txt");
            reader = new BufferedReader(new InputStreamReader(is));
            String keyWord;
            // 每次读取敏感词的一行
            while ((keyWord = reader.readLine()) != null) {
                // 把敏感词添加到前缀树
                this.addKeyWord(keyWord);
            }
        } catch (Exception e) {
            logger.error("加载敏感词文件失败：" + e.getMessage());
        } finally {
            try {
                is.close();
            } catch (IOException e) {
                e.printStackTrace();
            }
            try {
                reader.close();
            } catch (IOException e) {
                e.printStackTrace();
            }
        }

    }

    // 将一个敏感词添加到前缀树中
    private void addKeyWord(String keyWord) {
        TrieNode tempNode = rootNode;
        for (int i = 0; i < keyWord.length(); i++) {
            char c = keyWord.charAt(i);
            TrieNode subNode = tempNode.getSubNode(c);

            if (subNode == null) {
                // 初始化子节点
                subNode = new TrieNode();
                tempNode.addSubNode(c, subNode);
            }

            // 指向子节点，进入下一轮循环
            tempNode = subNode;

            // 设置结束标识
            if (i == keyWord.length() - 1) {
                tempNode.setKeyWordEnd(true);
            }
        }
    }

    /**
     * 过滤敏感词
     *
     * @param text 待过滤的文本
     * @return 过滤后的文本
     */
    public String filter(String text) {
        // 判空操作
        if (StringUtils.isBlank(text)) {
            return null;
        }

        // 指针1，指向树节点
        TrieNode tempNode = rootNode;
        // 指针2
        int begin = 0;
        // 指针3
        int position = 0;
        // 保存结果文本
        StringBuilder sb = new StringBuilder();

        while (begin < text.length()) {
            if (position < text.length()) {
                char c = text.charAt(position);

                // 跳过符号
                if (isSymbol(c)) {
                    // 若指针1处于根节点，将此符号计入结果，让指针2向后走一步
                    if (tempNode == rootNode) {
                        sb.append(c);
                        begin++;
                    }
                    // 无论符号在开头或中间，指针3都向后走一步
                    position++;
                    // 进入下一轮循环
                    continue;
                }

                // 检查下级节点
                tempNode = tempNode.getSubNode(c);
                if (tempNode == null) {
                    // 以begin开头的字符串不是敏感词
                    sb.append(text.charAt(begin));
                    // 进入下一个位置
                    begin++;
                    position = begin;
                    // 重新指向根节点
                    tempNode = rootNode;
                } else if (tempNode.isKeyWordEnd()) {
                    // 发现敏感词，将begin到position这一段的字符串替换掉
                    sb.append(REPLACEMENT);
                    // 进入下一个位置
                    position++;
                    begin = position;
                    // 重新指向根节点
                    tempNode = rootNode;
                } else {
                    // 还没有发现敏感词，继续检查下一个字符
                    position++;
                }
            } else { // 将最后一批字符计入结果(指针3到终点，指针2还没有到终点)
                // position遍历越界但仍未匹配到敏感词
                sb.append(text.charAt(begin));
                begin++;
                position = begin;
                // 重新指向根节点
                tempNode = rootNode;
            }
        }

        return sb.toString();
    }

    // 判断是否为符号
    private boolean isSymbol(Character c) {
        /**
         * isAsciiAlphanumeric如果是特殊字符返回false，如果是abc这种普通字符就返回true
         * 0x2E80 ~ 0x9FFF：代表东亚文字范围，(中文、日文、韩文这些就属于东亚文字)
         * c < 0x2E80 || c > 0x9FFF 意思就是排除东亚文字范围的其他符号
         */
        return !CharUtils.isAsciiAlphanumeric(c) && (c < 0x2E80 || c > 0x9FFF);
    }

}

/**
 * 过滤敏感词功能测试
 */
@SpringBootTest
@ContextConfiguration(classes = CommunityApplication.class)
public class SensitiveTests {

    @Autowired
    private SensitiveFilter sensitiveFilter;

    @Test
    public void testSensitiveFilter() {
        String text = "这里可以赌博,可以嫖娼,可以吸毒,可以开票,哈哈哈!";
        text = sensitiveFilter.filter(text);
        System.out.println(text);

        text = "这里可以☆赌☆博☆,可以☆嫖☆娼☆,可以☆吸☆毒☆,可以☆开☆票☆,哈哈哈!";
        text = sensitiveFilter.filter(text);
        System.out.println(text);
    }

}

// 将数据封装成json格式的字符串
    public static String getJSONString(int code, String msg, Map<String, Object> map) {
        // 创建一个json对象
        JSONObject json = new JSONObject();
        json.put("code", code);
        json.put("msg", msg);
        if (map != null) {
            // 遍历map中的每一个key
            for (String key : map.keySet()) {
                json.put(key, map.get(key));
            }
        }
        return json.toJSONString();
    }

    public static String getJSONString(int code, String msg) {
        return getJSONString(code, msg, null);
    }

    public static String getJSONString(int code) {
        return getJSONString(code, null, null);
    }

// 插入帖子
    public int addDiscussPost(DiscussPost post) {
        if (post == null) {
            throw new IllegalArgumentException("参数不能为空！");
        }
        // 转义HTML标记，如果标题中含有类似于<script>xxx</script>，会将标题转成普通文本而不会破坏网页显示内容
        post.setTitle(HtmlUtils.htmlEscape(post.getTitle()));
        post.setContent(HtmlUtils.htmlEscape(post.getContent()));
        // 过滤敏感词
        post.setTitle(sensitiveFilter.filter(post.getTitle()));
        post.setContent(sensitiveFilter.filter(post.getContent()));
        post.setStatus(0);
        post.setType(0);
        return discussPostMapper.insertDiscussPost(post);
    }

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

    @Autowired
    private DiscussPostService discussPostService;

    @Autowired
    private HostHolder hostHolder;

    @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, "您还没有登录哦！");
        }
        DiscussPost post = new DiscussPost();
        post.setUserId(user.getId());
        post.setTitle(title);
        post.setContent(content);
        post.setCreateTime(new Date());
        discussPostService.addDiscussPost(post);

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

}

/**
     * 根据id查询帖子
     *
     * @param id
     * @return
     */
    public DiscussPost findDiscusspostById(int id) {
        return discussPostMapper.selectDiscussPostById(id);
    }

@RequestMapping(path = "/detail/{discussPostId}", method = RequestMethod.GET)
    public String getDiscussPost(@PathVariable("discussPostId") int discussPostId, Model model) {
        // 查询帖子
        DiscussPost post = discussPostService.findDiscusspostById(discussPostId);
        model.addAttribute("post", post);
        // 作者
        User user = userService.findUserById(post.getUserId());
        model.addAttribute("user", user);
        return "/site/discuss-detail";
    }

@Service
public class CommentService {

    @Autowired
    private CommentMapper commentMapper;

    public List<Comment> findCommentsByEntity(int entityType, int entityId, int offset, int limit) {
        return commentMapper.selectCommentsByEntity(entityType, entityId, offset, limit);
    }

    public int findCommentCount(int entityType, int entityId) {
        return commentMapper.selectCountByEntity(entityType, entityId);
    }

}

/**
     * 根据id查询帖子
     *
     * @param id
     * @return
     */
    public DiscussPost findDiscusspostById(int id) {
        return discussPostMapper.selectDiscussPostById(id);
    }

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

    @Autowired
    private DiscussPostService discussPostService;

    @Autowired
    private HostHolder hostHolder;

    @Autowired
    private UserService userService;

    @Autowired
    private CommentService commentService;

    @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, "您还没有登录哦！");
        }
        DiscussPost post = new DiscussPost();
        post.setUserId(user.getId());
        post.setTitle(title);
        post.setContent(content);
        post.setCreateTime(new Date());
        discussPostService.addDiscussPost(post);

        // 报错的情况以后统一处理
        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) {
        // 查询帖子
        DiscussPost post = discussPostService.findDiscusspostById(discussPostId);
        model.addAttribute("post", post);
        // 作者
        User user = userService.findUserById(post.getUserId());
        model.addAttribute("user", user);

        // 查询评论信息
        // 评论分页信息
        page.setLimit(5);
        page.setPath("/discuss/detail/" + discussPostId);
        page.setRows(post.getCommentCount());

        /**
         * 说明：
         * 评论：给帖子的评论
         * 回复：给评论的评论
         * vo：view object
         */
        // 查询当前帖子的所有评论，下面这个commentList是评论列表
        List<Comment> commentList = commentService.findCommentsByEntity(ENTITY_TYPE_POST, post.getId(), page.getOffset(), page.getLimit());

        // 评论的vo列表
        List<Map<String, Object>> commentVoList = new ArrayList<>();
        if (commentList != null) {
            for (Comment comment : commentList) {
                // 一个评论的vo
                Map<String, Object> commentVo = new HashMap<>();
                // 往vo里添加评论
                commentVo.put("comment", comment);
                // 往vo里添加评论的作者
                commentVo.put("user", userService.findUserById(comment.getUserId()));

                // 下面这个replyList是回复列表，（offset：0，limit：Integer.MAX_VALUE  表示有多少评论就查多少评论，不分页）
                List<Comment> replyList = commentService.findCommentsByEntity(ENTITY_TYPE_COMMENT, comment.getId(), 0, Integer.MAX_VALUE);

                // 回复的vo列表
                List<Map<String, Object>> replyVoList = new ArrayList<>();
                if (replyList != null) {
                    for (Comment reply : replyList) {
                        // 一个回复的vo
                        Map<String, Object> replyVo = new HashMap<>();
                        // 往vo里添加回复
                        replyVo.put("reply", reply);
                        // 往vo里添加回复的作者
                        replyVo.put("user", userService.findUserById(reply.getUserId()));
                        /**
                         * 往vo里添加回复的目标
                         * target：0表示普通回复
                         * target：非0 表示回复作者的评论
                         */
                        User target = reply.getTargetId() == 0 ? null : userService.findUserById(reply.getTargetId());
                        replyVo.put("target", target);

                        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";
    }

}

/**
     * 更新帖子评论数量
     *
     * @param id
     * @param commentCount
     * @return
     */
    public int updateCommentCount(int id, int commentCount) {
        return discussPostMapper.updateCommentCount(id, commentCount);
    }

@Transactional(isolation = Isolation.READ_COMMITTED, propagation = Propagation.REQUIRED)
    public int addComment(Comment comment) {
        if (comment == null) {
            throw new IllegalArgumentException("参数不能为空！");
        }
        // 添加评论
        // 对评论内容的特殊字符进行转义
        comment.setContent(HtmlUtils.htmlEscape(comment.getContent()));
        // 对评论内容进行敏感词过滤
        comment.setContent(sensitiveFilter.filter(comment.getContent()));
        int rows = commentMapper.insertComment(comment);

        // 更新帖子的评论数量
        if (comment.getEntityType() == ENTITY_TYPE_POST) {
            int count = commentMapper.selectCountByEntity(comment.getEntityType(), comment.getEntityId());
            discussPostService.updateCommentCount(comment.getEntityId(), count);
        }

        return rows;
    }

@Controller
@RequestMapping("/comment")
public class CommentController {

    @Autowired
    private CommentService commentService;

    @Autowired
    private HostHolder hostHolder;

    @RequestMapping(path = "/add/{discussPostId}", method = RequestMethod.POST)
    public String addComment(@PathVariable("discussPostId") int discussPostId, Comment comment) {
        comment.setUserId(hostHolder.getUser().getId());
        comment.setStatus(0);
        comment.setCreateTime(new Date());
        commentService.addComment(comment);

        // 重定向到帖子详情页
        return "redirect:/discuss/detail/" + discussPostId;
    }

}