Override public List getQuestionsByBankIdInteger bankId String username 协同过滤 获取历史考试中错题 User user = userServicegetUserByUsernameusername; QueryWrapperExamRecord wrapper = new QueryWrapper;

// 获取用户做过的题目 List userQuestionIds = new ArrayList<>(); List exams = examMapper.selectList(new QueryWrapper().eq("user_id", user.getId())); for (Exam exam : exams) { String questionIds = exam.getQuestionIds(); if (!StringUtils.isEmpty(questionIds)) { String[] split = questionIds.split(","); for (String s : split) { userQuestionIds.add(Integer.valueOf(s)); } } }

// 根据用户做过的题目，查询其他用户做过的题目
List<Integer> similarUserIds = collaborativeFilteringService.getSimilarUserIds(user.getId());
List<Integer> similarUserQuestionIds = new ArrayList<>();
for (Integer similarUserId : similarUserIds) {
    List<Exam> similarUserExams = examMapper.selectList(new QueryWrapper<Exam>().eq("user_id", similarUserId));
    for (Exam exam : similarUserExams) {
        String questionIds = exam.getQuestionIds();
        if (!StringUtils.isEmpty(questionIds)) {
            String[] split = questionIds.split(",");
            for (String s : split) {
                Integer questionId = Integer.valueOf(s);
                if (!userQuestionIds.contains(questionId) && !similarUserQuestionIds.contains(questionId)) {
                    similarUserQuestionIds.add(questionId);
                }
            }
        }
    }
}

// 根据其他用户做过的题目，查询题库中的题目
List<Question> similarQuestions = null;
if (CollectionUtils.isEmpty(similarUserQuestionIds)) {
    similarQuestions = questionMapper.selectList(
            new QueryWrapper<Question>().like("qu_bank_name",
                    bank.getBankName()).in("qu_type", 1, 2, 3));
} else {
    similarQuestions = questionMapper.selectList(
            new QueryWrapper<Question>().like("qu_bank_name",
                    bank.getBankName()).in("qu_type", 1, 2, 3)
                    .in("id", similarUserQuestionIds));
}

// 合并两部分题目
List<Question> result = new ArrayList<>();
result.addAll(questions);
result.addAll(similarQuestions);
return result;