LambdaQueryWrapper<TrnUserCourseTrainDO> queryWrapper = new LambdaQueryWrapper<>(); queryWrapper.eq(TrnUserCourseTrainDO::getUserId, userId) .eq(TrnUserCourseTrainDO::getCourseId, courseId) .eq(TrnUserCourseTrainDO::getTrainId, createReqVO.getTrainId()) .last("for update"); TrnUserCourseTrainDO trnUserCourseTrainDO = trnUserCourseTrainMapper.selectOne(queryWrapper); if (trnUserCourseTrainDO == null) { TrnUserCourseTrainDO trainDO = new TrnUserCourseTrainDO(); BeanUtils.copyProperties(createReqVO, trainDO); trainDO.setDayTime(now); trainDO.setUserId(userId); //视频时长 Integer videoDuration = trnCourseDO.getVideoDuration(); trainDO.setVideoTime(videoDuration); String examPercentage = decimalFormat.format(((float) courseDurationStudy / videoDuration) * 100) + "%"; trainDO.setStudySchedule(examPercentage); trainDO.setCourseDurationStudy(courseDurationStudy); // 插入 trnUserCourseTrainMapper.insert(trainDO); } else { TrnUserCourseTrainDO trainDO = new TrnUserCourseTrainDO(); BeanUtils.copyProperties(createReqVO, trainDO); trainDO.setDayTime(now); trainDO.setUserId(userId); //视频时长 Integer videoDuration = trnCourseDO.getVideoDuration(); trainDO.setVideoTime(videoDuration); //已存在的学习进度 Integer doCourseDurationStudy = trnUserCourseTrainDO.getCourseDurationStudy(); if (courseDurationStudy > doCourseDurationStudy) { String examPercentage = decimalFormat.format(((float) courseDurationStudy / videoDuration) * 100) + "%"; trainDO.setStudySchedule(examPercentage); trainDO.setCourseDurationStudy(courseDurationStudy); } else { trainDO.setStudySchedule(trnUserCourseTrainDO.getStudySchedule()); trainDO.setCourseDurationStudy(doCourseDurationStudy); } trainDO.setId(trnUserCourseTrainDO.getId()); trnUserCourseTrainMapper.updateById(trainDO); } 这段代码怎么改为不会被插入脏数据的

为了避免插入脏数据，你可以使用数据库的事务来确保数据的一致性。在这段代码中，你可以在插入或更新操作之前开启一个事务，在操作完成后提交事务。如果发生异常，可以回滚事务以保持数据的一致性。

下面是将代码改为使用事务的示例：

import org.springframework.transaction.annotation.Transactional;

@Transactional(rollbackFor = Exception.class)
public void saveOrUpdateTrnUserCourseTrainDO(Long userId, Long courseId, CreateReqVO createReqVO, TrnCourseDO trnCourseDO) {
    LambdaQueryWrapper<TrnUserCourseTrainDO> queryWrapper = new LambdaQueryWrapper<>();
    queryWrapper.eq(TrnUserCourseTrainDO::getUserId, userId)
            .eq(TrnUserCourseTrainDO::getCourseId, courseId)
            .eq(TrnUserCourseTrainDO::getTrainId, createReqVO.getTrainId())
            .last("for update");

    TrnUserCourseTrainDO trnUserCourseTrainDO = trnUserCourseTrainMapper.selectOne(queryWrapper);

    if (trnUserCourseTrainDO == null) {
        // 插入
        insertTrnUserCourseTrain(userId, createReqVO, trnCourseDO);
    } else {
        updateTrnUserCourseTrain(trnUserCourseTrainDO, createReqVO, trnCourseDO);
    }
}

private void insertTrnUserCourseTrain(Long userId, CreateReqVO createReqVO, TrnCourseDO trnCourseDO) {
    TrnUserCourseTrainDO trainDO = new TrnUserCourseTrainDO();
    BeanUtils.copyProperties(createReqVO, trainDO);
    trainDO.setDayTime(now);
    trainDO.setUserId(userId);
    // 视频时长
    Integer videoDuration = trnCourseDO.getVideoDuration();
    trainDO.setVideoTime(videoDuration);

    String examPercentage = decimalFormat.format(((float) courseDurationStudy / videoDuration) * 100) + "%";
    trainDO.setStudySchedule(examPercentage);
    trainDO.setCourseDurationStudy(courseDurationStudy);

    trnUserCourseTrainMapper.insert(trainDO);
}

private void updateTrnUserCourseTrain(TrnUserCourseTrainDO trnUserCourseTrainDO, CreateReqVO createReqVO, TrnCourseDO trnCourseDO) {
    TrnUserCourseTrainDO trainDO = new TrnUserCourseTrainDO();
    BeanUtils.copyProperties(createReqVO, trainDO);
    trainDO.setDayTime(now);
    trainDO.setUserId(userId);
    // 视频时长
    Integer videoDuration = trnCourseDO.getVideoDuration();
    trainDO.setVideoTime(videoDuration);

    // 已存在的学习进度
    Integer doCourseDurationStudy = trnUserCourseTrainDO.getCourseDurationStudy();

    if (courseDurationStudy > doCourseDurationStudy) {
        String examPercentage = decimalFormat.format(((float) courseDurationStudy / videoDuration) * 100) + "%";
        trainDO.setStudySchedule(examPercentage);
        trainDO.setCourseDurationStudy(courseDurationStudy);
    } else {
        trainDO.setStudySchedule(trnUserCourseTrainDO.getStudySchedule());
        trainDO.setCourseDurationStudy(doCourseDurationStudy);
    }
    trainDO.setId(trnUserCourseTrainDO.getId());

    trnUserCourseTrainMapper.updateById(trainDO);
}

在这个示例中，我们在`saveOrUpdateTrnUserCourseTrainDO`方法上使用了`@Transactional`注解来开启事务，并指定了回滚策略为`Exception.class`。在插入和更新的方法中，分别提取出来作为单独的方法，以便在事务中进行操作。

这样，当发生异常时，事务会回滚，确保数据的一致性。如果操作成功完成，事务会被提交，数据会被持久化到数据库中。