项目复习（1）
第一天
==和equals
为什么userId为2的时候判断相等可以成立，而userId是129的时候判断相等不成立呢？
这是因为userId是Long类型包装类。包装类为了提高性能，减少内存占用，采用了享元模式，提前将-128~127之间的Long包装类提前创建出来，共享使用。
因此只要大小范围在者之间的数字，只要值相同，使用的都是享元模式中提供的同一个对象。杰克的id是2，恰好在范围内；而萝丝的id是129，刚好超过了这个范围。这就导致了杰克可以删除自己订单，而萝丝无法删除的现象。
第二天
1.添加课程到课表
2.分页查询我的课程
⭐Mybatis-Plus的分页查询
// select * from learning_lesson where user_id = #{userId} order by latest_learn_time
Page<LearningLesson> page = lambdaQuery().eq(LearningLesson::getUserId, userId) // where user_id = #{userId}.page(query.toMpPage("latest_learn_time", false));⭐list集合装成map
可以防止双重for循环取list的集合
用map可以for循环一个集合，然后集合里面直接拿map的键值
//把cinfos转成map--方便查询课程名字courseName；课程封面courseCoverUrl 课程章节数量sections
Map<Long, CourseSimpleInfoDTO> cInfoMap = cinfos.stream().collect(Collectors.toMap(CourseSimpleInfoDTO::getId, c -> c));3.查询我正在学习的课程
Mybatis-Plus的自定义语句和按照什么排序
//2.查询正在学习的课程---按照lastest_learn_time排序，取第一个
//select * from learning_lesson
//where user_id = #{userId} and status = 1 order by latest_learn_time limit 1
LearningLesson lesson = this.lambdaQuery().eq(LearningLesson::getUserId, userId).eq(LearningLesson::getStatus,LEARNING).orderByDesc(LearningLesson::getLatestLearnTime).last("limit 1").one();第三天
1.创建学习计划
无
⭐2.查询我的学习计划
查询本周学习计划总数--本周计算学习小节量
//select sum(week_frep) ad plansTotal from learning_lesson
//where user_id = #{userId}
//and status in(0,1)
//and plan_status = 1
QueryWrapper<LearningLesson> wrapper = new QueryWrapper<>();
wrapper.select("sum(week_freq) as plansTotal");
wrapper.eq("user_id",userId);
wrapper.in("status", LEARNING,NOT_BEGIN);
wrapper.eq("plan_status", PLAN_RUNNING);
//Map-->key = plansTotal;value= [sum(week_freq)]---是BigDecimal类型
Map<String, Object> map = this.getMap(wrapper);3.查询学习记录
无
⭐4.提交学习记录
逻辑很重要
//1.获取用户id
Long userId = UserContext.getUser();
//2.判断是考试还是视频
boolean isFinished = false;//表示是否学完
if (dto.getSectionType() == SectionType.VIDEO) {//考试isFinished = isExam(userId, dto);
} else if (dto.getSectionType() == SectionType.EXAM) {//视频isFinished = isVideo(userId, dto);
}
//5.更新课表数据
handleLessonData(dto, isFinished);/*** 处理视频** @param userId* @param dto* @return*/
private boolean isVideo(Long userId, LearningRecordFormDTO dto) {//1.先判断是否是第一次学习LearningRecord record = this.lambdaQuery().eq(LearningRecord::getUserId, userId).eq(LearningRecord::getLessonId, dto.getLessonId()).eq(LearningRecord::getSectionId, dto.getSectionId()).one();//2.第一次学习--新增学习记录if (record == null) {//2.第一次学习--新增学习记录LearningRecord learningRecord = BeanUtils.copyBean(dto, LearningRecord.class);learningRecord.setUserId(userId);learningRecord.setFinished(false);boolean update = this.save(learningRecord);if (!update) {throw new DbException("新增学习记录失败");}}//3.不是第一次学习--更新学习记录--moment//finished和finishTime取决与是否第一次学完//3.1判断是否第一次学完Boolean finished = record.getFinished();//是否学完Integer moment = record.getMoment();//视频的当前观看时长，单位秒Integer duration = dto.getDuration();//视频总时长boolean isFinished = !finished && moment * 2 > duration;//是否第一次学完boolean update = this.lambdaUpdate().set(LearningRecord::getMoment, dto.getMoment()).set(isFinished, LearningRecord::getFinished, isFinished).set(isFinished, LearningRecord::getFinishTime, dto.getCommitTime()).eq(LearningRecord::getUserId, userId).eq(LearningRecord::getLessonId, dto.getLessonId()).eq(LearningRecord::getSectionId, dto.getSectionId()).update();if (!update) {throw new DbException("更新学习记录失败");}return isFinished;
}/*** 处理考试--是考试默认学完** @param userId* @param dto* @return*/
public boolean isExam(Long userId, LearningRecordFormDTO dto) {//3.1是考试---新增学习记录---learning_record表LearningRecord learningRecord = BeanUtils.copyBean(dto, LearningRecord.class);learningRecord.setUserId(userId);learningRecord.setFinished(true);learningRecord.setFinishTime(dto.getCommitTime());boolean update = this.save(learningRecord);if (!update) {throw new DbException("新增学习记录失败");}return true;
}/*** 课表数据处理* @param dto* @param isFinished*/
private void handleLessonData(LearningRecordFormDTO dto, boolean isFinished) {//查询课表LearningLesson lesson = lessonService.getById(dto.getLessonId());if(lesson==null){throw new BadRequestException("课表不存在");}//1.判断是否第一次学完boolean allFinished = false;if(isFinished){//2远程调用课程服务得到课程消息--小节总数CourseFullInfoDTO cinfo = courseClient.getCourseInfoById(lesson.getCourseId(), false, false);if(cinfo==null){throw new BadRequestException("课程不存在");}Integer sectionNum = cinfo.getSectionNum();//课程总小节数//判断是否全部学完Integer learnedSections = lesson.getLearnedSections();//已学完小节数量allFinished = learnedSections +1 >= sectionNum;}//3.1更新课表lessonService.lambdaUpdate().set(lesson.getStatus()==LessonStatus.NOT_BEGIN, LearningLesson::getPlanStatus, LessonStatus.LEARNING).set(allFinished, LearningLesson::getStatus, LessonStatus.FINISHED).set(LearningLesson::getLatestSectionId, dto.getSectionId()).set(LearningLesson::getLatestLearnTime, dto.getCommitTime()).set(allFinished,LearningLesson::getLearnedSections, lesson.getLearnedSections()+1).update();}5.定时任务
1.首先先在启动类加上
@EnableScheduling//开启定时任务
2.方法上加上
@Scheduled(cron = "0 0/1 * * * ?")//每分钟
public void check() {log.info("开始检查课程状态");}