多层级查询

注意：要注意代码顺序 查询层级数据代码放前面，查询条件放后面

    if (StringUtils.isBlank(params.getDocType())) {
            params.setDocType(DOC_TDCTYPE);
        }
        String docName = mapper.findByDocInfo(params.getDocType());
        List<ExpertApprovalOpinionsVO> expertApprovalOpinionsVOS = new ArrayList<>();
        String opinion = params.getApprovalOpinions();
        String chapterName = params.getChapterName();
        String approvalPerson = params.getApprovalPerson();
        Criteria criteria = new Criteria();
        Criteria[] criteriaArray = new Criteria[0];

        List<AggregationOperation> operations = new ArrayList<>();
		//分页条件
        int skip = (page - 1) * pageSize;
        AggregationOperation skipOperation = Aggregation.skip((long) skip);
        AggregationOperation limitOperation = Aggregation.limit((long) pageSize);
        //多层级查询条件
        // 展开第一层级数组commentThreads
        AggregationOperation unwind1 = Aggregation.unwind(COMMENTTHREADS);
        // 展开第二层级数组commentThreads.comments
        AggregationOperation unwind2 = Aggregation.unwind(COMMENTTHREADS_COMMENTS);
        operations.add(unwind1);
        operations.add(unwind2);
        
		//添加条件查询 ，单个查询条件和 多个 查询值
        if (StringUtils.isNotBlank(chapterName)) {
            //查詢出 章节key 用于根据章节key查询 MongoDB 的章节批注意见
            List<Map<String, Object>> modelKeyList = mapper.findByModelKey(params);
            if (!modelKeyList.isEmpty()) {
                // 匹配满足单次正则表达式的文档
                if (modelKeyList.size() == 1) {
                    Pattern pattern = Pattern.compile(ObjectUtils.toString(modelKeyList.get(0).get(MODEL_KEY)), Pattern.CASE_INSENSITIVE); // 根据您的需要指定模糊匹配的正则表达式和匹配选项
                    MatchOperation match = Aggregation.match(Criteria.where(KEY).regex(pattern));
                    operations.add(match);
                } else {
                    // 匹配满足批量正则表达式的文档
                    // 章节key集合
                    List<String> threadId = modelKeyList.stream()
                            .map(map -> map.get(MODEL_KEY) != null ? String.valueOf(map.get(MODEL_KEY)) : null)
                            .filter(Objects::nonNull)
                            .collect(Collectors.toList());
                    // 构建匹配条件列表
                    List<Criteria> criteriaList = new ArrayList<>();
                    for (String pattern : threadId) {
                        // 构造正则表达式匹配条件
                        String regexPattern = ".*" + Pattern.compile(pattern) + ".*";
                        criteriaList.add(Criteria.where(KEY).regex(regexPattern));
                    }
                    // 使用$or操作符组合多个条件
                    Criteria orCriteria = new Criteria().orOperator(criteriaList.toArray(new Criteria[criteriaList.size()]));

                    AggregationOperation match2 = Aggregation.match(orCriteria);
                    operations.add(match2);
                }
            } else {
                return expertApprovalOpinionsVOS;
            }

        }
        if (StringUtils.isNotBlank(approvalPerson)) {
            //模糊查询出用户
            List<Map<String, Object>> userList = mapper.findByUser(params);
            if (!userList.isEmpty()) {

                //用户集合
                List<String> authorId = userList.stream()
                        .map(map -> map.get(USER_ID) != null ? String.valueOf(map.get(USER_ID)) : null)
                        .filter(Objects::nonNull)
                        .collect(Collectors.toList());
                criteria = Criteria.where(COMMENTTHREADS_COMMENTS_AUTHORID).in(authorId);
                AggregationOperation match = Aggregation.match(new Criteria().andOperator(criteria));
                operations.add(match);
            } else {
                return expertApprovalOpinionsVOS;
            }
        }
        if (StringUtils.isNotBlank(opinion)) {
            Pattern pattern1 = Pattern.compile(opinion, Pattern.CASE_INSENSITIVE);
            criteria = Criteria.where(COMMENTTHREADS_COMMENTS_CONTENT).regex(pattern1);
            AggregationOperation match2 = Aggregation.match(criteria);
            operations.add(match2);
        }
        /**
         * project 新的 数据 包含 "crt_time", "nodeId", "processInstanceId", "nodeCrtTime"
         * andExclude 排除 "_id"
         * andExpression 执行 表达式 ，取出对应的 数据值
         * as 生成的 新数据的 名称
         */
        operations.add(Aggregation.project("crt_time", "nodeId", "processInstanceId", "nodeCrtTime").andExclude("_id").andExpression(COMMENTTHREADS_COMMENTS).as(COMMENTS)
        );
        operations.add(Aggregation.sort(Sort.Direction.DESC, "crt_time"));
        operations.add(skipOperation);
        operations.add(limitOperation);
        Aggregation aggregation = Aggregation.newAggregation(operations);

        //查询
        AggregationResults<Map> result = template.aggregate(aggregation, params.getDocType() + ".approvals", Map.class);
        //获取结果
        List<Map> mappedResults = result.getMappedResults();