天机学堂踩坑笔记

相关资源链接：

Md笔记：蓝奏云地址

在线笔记：飞书笔记地址

相关视频教程及配套课件：

链接：百度云地址

提取码：hmz1

1. Day01 初识项目

1.1 OpenEuler 22.03LTS yum换源失败

适用于OpenEuler版本为22.03LTS，需要指定具体版本。

yum换源，备份源文件并更新，文件位置：/etc/yum.repos.d/openEuler.repo

[OS]
name=OS
baseurl=https://repo.huaweicloud.com/openeuler/openEuler-22.03-LTS/OS/$basearch/
enabled=1
gpgcheck=1
gpgkey=https://repo.huaweicloud.com/openeuler/openEuler-22.03-LTS/OS/$basearch/RPM-GPG-KEY-openEuler
[everything]
name=everything
baseurl=https://repo.huaweicloud.com/openeuler/openEuler-22.03-LTS/everything/$basearch/
enabled=1
gpgcheck=1
gpgkey=https://repo.huaweicloud.com/openeuler/openEuler-22.03-LTS/everything/$basearch/RPM-GPG-KEY-openEuler
[EPOL]
name=EPOL
baseurl=https://repo.huaweicloud.com/openeuler/openEuler-22.03-LTS/EPOL/multi_version/OpenStack/Train/$basearch/
enabled=1
gpgcheck=1
gpgkey=https://repo.huaweicloud.com/openeuler/openEuler-22.03-LTS/OS/$basearch/RPM-GPG-KEY-openEuler
[EPOL5]
name=EPOL5
baseurl=https://repo.huaweicloud.com/openeuler/openEuler-22.03-LTS/EPOL/main/$basearch/
enabled=1
gpgcheck=1
gpgkey=https://repo.huaweicloud.com/openeuler/openEuler-22.03-LTS/OS/$basearch/RPM-GPG-KEY-openEuler
[EPOL2]
name=EPOL2
baseurl=https://repo.huaweicloud.com/openeuler/openEuler-22.03-LTS/EPOL/multi_version/OpenStack/Wallaby/$basearch/
enabled=1
gpgcheck=1
gpgkey=https://repo.huaweicloud.com/openeuler/openEuler-22.03-LTS/OS/$basearch/RPM-GPG-KEY-openEuler
[EPOL3]
name=EPOL3
baseurl=https://repo.huaweicloud.com/openeuler/openEuler-22.03-LTS/EPOL/update/multi_version/OpenStack/Train/$basearch/
enabled=1
gpgcheck=1
gpgkey=https://repo.huaweicloud.com/openeuler/openEuler-22.03-LTS/OS/$basearch/RPM-GPG-KEY-openEuler
[EPOL4]
name=EPOL4
baseurl=https://repo.huaweicloud.com/openeuler/openEuler-22.03-LTS/EPOL/update/multi_version/OpenStack/Wallaby/$basearch/
enabled=1
gpgcheck=1
gpgkey=https://repo.huaweicloud.com/openeuler/openEuler-22.03-LTS/OS/$basearch/RPM-GPG-KEY-openEuler
[debuginfo]
name=debuginfo
baseurl=https://repo.huaweicloud.com/openeuler/openEuler-22.03-LTS/debuginfo/$basearch/
enabled=1
gpgcheck=1
gpgkey=https://repo.huaweicloud.com/openeuler/openEuler-22.03-LTS/debuginfo/$basearch/RPM-GPG-KEY-openEuler
[source]
name=source
baseurl=https://repo.huaweicloud.com/openeuler/openEuler-22.03-LTS/source/
enabled=1
gpgcheck=1
gpgkey=https://repo.huaweicloud.com/openeuler/openEuler-22.03-LTS/source/RPM-GPG-KEY-openEuler
[update]
name=update
baseurl=https://repo.huaweicloud.com/openeuler/openEuler-22.03-LTS/update/$basearch/
enabled=1
gpgcheck=1
gpgkey=https://repo.huaweicloud.com/openeuler/openEuler-22.03-LTS/OS/$basearch/RPM-GPG-KEY-openEuler

经测试，华为云镜像下载速度高于阿里云

1.2 运行docker-compose.yml文件失败

错误信息如下：

ERROR: The Compose file './docker-compose.yml' is invalid because: networks.name Additional properties are not allowed ('name' was unexpected)

解决方法：运行以下命令将docker-compose升级，如1.28.5版本

# 下载
curl -L https://github.com/docker/compose/releases/download/1.28.5/docker-compose-`uname -s`-`uname -m` -o /usr/local/bin/docker-compose
# 安装
chmod +x /usr/local/bin/docker-compose

参考链接无法在docker-compose中提供网络名称

1.3 Docker安装seata出错

错误信息如下：

apm-skywalking not enabled
JMX disabled
Affected JVM parameters: -Dlog.home=/root/logs/seata -server -Dloader.path=/lib -Xmx2048m -Xms2048m -Xss640k -XX:SurvivorRatio=10 -XX:MetaspaceSize=128m -XX:MaxMetaspaceSize=256m -XX:MaxDirectMemorySize=1024m -XX:-OmitStackTraceInFastThrow -XX:-UseAdaptiveSizePolicy -XX:+HeapDumpOnOutOfMemoryError -XX:HeapDumpPath=/root/logs/seata/java_heapdump.hprof -XX:+DisableExplicitGC -Xloggc:/root/logs/seata/seata_gc.log -verbose:gc -XX:+PrintGCDetails  -XX:+PrintGCDateStamps -XX:+PrintGCTimeStamps -XX:+UseGCLogFileRotation -XX:NumberOfGCLogFiles=10 -XX:GCLogFileSize=100M -XX:+UnlockExperimentalVMOptions -XX:+UseG1GC -Dio.netty.leakDetectionLevel=advanced -Dapp.name=seata-server -Dapp.pid=1 -Dapp.home=/ -Dbasedir=/ 
OpenJDK 64-Bit Server VM warning: Cannot open file /root/logs/seata/seata_gc.log due to No such file or directory
Exception in thread "main" java.lang.IllegalArgumentException: Cannot instantiate interface org.springframework.context.ApplicationListener : io.seata.server.ServerApplicationListener
	at org.springframework.boot.SpringApplication.createSpringFactoriesInstances(SpringApplication.java:450)
	at org.springframework.boot.SpringApplication.getSpringFactoriesInstances(SpringApplication.java:432)
	at org.springframework.boot.SpringApplication.getSpringFactoriesInstances(SpringApplication.java:425)
	at org.springframework.boot.SpringApplication.(SpringApplication.java:268)
	at org.springframework.boot.SpringApplication.(SpringApplication.java:246)
	at org.springframework.boot.SpringApplication.run(SpringApplication.java:1300)
	at org.springframework.boot.SpringApplication.run(SpringApplication.java:1289)
	at org.apache.seata.server.ServerApplication.main(ServerApplication.java:30)
Caused by: java.lang.ClassNotFoundException: io.seata.server.ServerApplicationListener
	at java.net.URLClassLoader.findClass(URLClassLoader.java:387)
	at java.lang.ClassLoader.loadClass(ClassLoader.java:418)
	at sun.misc.Launcher$AppClassLoader.loadClass(Launcher.java:352)
	at java.lang.ClassLoader.loadClass(ClassLoader.java:351)
	at java.lang.Class.forName0(Native Method)
	at java.lang.Class.forName(Class.java:348)
	at org.springframework.util.ClassUtils.forName(ClassUtils.java:291)
	at org.springframework.boot.SpringApplication.createSpringFactoriesInstances(SpringApplication.java:443)
	... 7 more

关键一条：

OpenJDK 64-Bit Server VM warning: Cannot open file /root/logs/seata/seata_gc.log due to No such file or directory

尝试新建该目录和文件并授权，无效

尝试修改seata目录下application.yml配置文件中的日志文件输出路径：

# 日志配置
logging:
  config: classpath:logback-spring.xml
  file:
    path: /usr/local/src/seata/logs/
  # path: ${user.home}/logs/seata

seata却能够正常启动

seata修改完配置文件后启动：

docker run -d --name seata  -p 8099:8099  -p 7099:7099  -e SEATA_IP=192.168.150.101  -v /usr/local/src/seata:/seata-server/resources --network tjxt  --restart always --ulimit nofile=1024    seataio/seata-server:1.5.2

1.4 Jenkins启动报错

错误信息：

DEPRECATED: The legacy builder is deprecated and will be removed in a future release.
            Install the buildx component to build images with BuildKit:
            https://docs.docker.com/go/buildx/
permission denied while trying to connect to the Docker daemon socket at unix:///var/run/docker.sock: Post "http://%2Fvar%2Frun%2Fdocker.sock/v1.24/build?buildargs=%7B%22JAVA_OPTS%22%3A%22-Xms300m+-Xmx300m%22%7D&cachefrom=%5B%5D&cgroupparent=&cpuperiod=0&cpuquota=0&cpusetcpus=&cpusetmems=&cpushares=0&dockerfile=Dockerfile&labels=%7B%7D&memory=0&memswap=0&networkmode=default&rm=1&shmsize=0&t=tj-gateway&target=&ulimits=%5B%5D&version=1": dial unix /var/run/docker.sock: connect: permission denied

很明显 permission denied权少权限，这里因为是本地虚拟机，所有直接：

chmod 777 -R /var/run/docker.sock

1.5 修改nacos实力权重或者对某实例下线报错

在Nacos控制台进行上述操作，错误信息

caused: errCode: 500, errMsg: do metadata operation failed ;caused: com.alibaba.nacos.consistency.exception.ConsistencyException: 
The Raft Group [naming_instance_metadata] did not find the Leader node;caused: The Raft Group [naming_instance_metadata] did not
find the Leader node;

原因：Nacos采用raft算法来计算Leader,并且会记录上次启动的集群地址，所以当我们自己的服务器IP改变时（网络环境不稳定，如WIFI,IP地址也经常变化)，导致raft记录的集群地址失效，导致选Leader出现问题，

解决方法：删除Nacos根目录下data文件夹下的protocol文件夹，重启nacos即可

#相关命令
#进入nacos容器
docker exec -it nacos /bin/bash
#进入nacos的data文件
cd data
#删除protocol文件夹
rm -rf protocol/
#退出容器
exit
#重启nacos容器
docker restart nacos

1.6 OpenEuler 22.03LTS系统安装问题

在VMware16 pro安装一直黑屏，无法进行安装系统

方法：VMware16 pro版本不兼容问题，升级到VMware 17pro

2. Day02 我的课表

2.1 数据库连接配置错误

错误信息如下：

java.sql.SQLNonTransientConnectionException: Could not create connection to database server. Attempted reconnect 3 times. Giving up.
Caused by: com.mysql.cj.exceptions.CJException: Unknown database 'tj_learning'

原因及解决方法：以为是拉去nacos共享配置出错，经排查是新建数据库时名称写错为 tj-learning ，修改为tj_learning

2.2 RabbitMQ消息监听

第一次接触，特此记录下。

LessonChangeListener.java

package com.tianji.learning.mq;
import cn.hutool.core.collection.CollUtil;
import com.tianji.api.dto.trade.OrderBasicDTO;
import com.tianji.common.constants.MqConstants;
import com.tianji.learning.service.ILearningLessonService;
import lombok.RequiredArgsConstructor;
import lombok.extern.slf4j.Slf4j;
import org.springframework.amqp.core.ExchangeTypes;
import org.springframework.amqp.rabbit.annotation.Exchange;
import org.springframework.amqp.rabbit.annotation.Queue;
import org.springframework.amqp.rabbit.annotation.QueueBinding;
import org.springframework.amqp.rabbit.annotation.RabbitListener;
import org.springframework.stereotype.Component;
/**
 * @author: hong.jian
 * @date 2024-03-08 17:37
 */
@Component
@Slf4j
@RequiredArgsConstructor  // 使用构造器，lombok会在编译器生成相应的方法
public class LessonChangeListener {
    private final ILearningLessonService lessonService;
    /***
     * MQ消息发送
     *         rabbitMqHelper.send(
     *                 MqConstants.Exchange.ORDER_EXCHANGE, // Exchange
     *                 MqConstants.Key.ORDER_PAY_KEY,    // Key
     *                 OrderBasicDTO.builder()
     *                         .orderId(orderId)
     *                         .userId(userId)
     *                         .courseIds(cIds)
     *                         .finishTime(order.getFinishTime())
     *                         .build()
     *         );
     *
     * @param dto 接受的参数类型为OrderBasicDTO
     */
    @RabbitListener(bindings = @QueueBinding(value = @Queue(value = "learning.lesson.pay.queue", durable = "true"),
            exchange = @Exchange(value = MqConstants.Exchange.ORDER_EXCHANGE, type = ExchangeTypes.TOPIC),
            key = MqConstants.Key.ORDER_PAY_KEY))
    public void onMsg(OrderBasicDTO dto) {
        log.info("LessonChangeListener接收消息，用户{}，添加课程{}", dto.getUserId(), dto.getCourseIds());
        // 校验
        if (dto.getUserId() == null
                || dto.getOrderId() == null
                || CollUtil.isEmpty(dto.getCourseIds())) {
            // 这里是接受MQ消息，中断即可，若抛异常，则会开启重试
            return;
        }
        // 保存课程到课表
        lessonService.addUserLesson(dto.getUserId(),dto.getCourseIds());
    }
}

相关概念详见MQ基础.md

3. Day03 学习计划和进度

3.1 前端接口请求参数异常

请求/ls/lessons/plans参数如图：

断电调试时接口如下，并未收到参数：

解决方法：前端使用application/json进行传递参数，需要使用@RequestBody进行接收

/**
 * 创建学习计划
 *
 */
@ApiOperation("创建学习计划")
@PostMapping("/plans")
public void createLessonPlan(@RequestBody LearningPlanFormDTO dto) {
    learningLessonService.createLessonPlan(dto.getCourseId(),dto.getFreq());
}

4. Day04 改造提交学习记录

4.1 学习记录改造后出现NPE

控制台日志如下：

17:41:51.233-[DESKTOP-CSPG5LG][4dae58c8c33e4b1a9de75ec60e90c60a]--DEBUG 24112 --- [nio-8090-exec-1] c.t.l.m.LearningRecordMapper.update      : ==> Parameters: 137(Integer), true(Boolean), 2024-03-11T17:41:51(LocalDateTime), 1767122184276279297(Long)
17:41:51.237-[DESKTOP-CSPG5LG][4dae58c8c33e4b1a9de75ec60e90c60a]--DEBUG 24112 --- [nio-8090-exec-1] c.t.l.m.LearningRecordMapper.update      :  
java.lang.NullPointerException: null
	at com.tianji.learning.util.LearningRecordDelayTaskHandler.cleanRecordCache(LearningRecordDelayTaskHandler.java:148) ~[classes/:na]
	at com.tianji.learning.service.impl.LearningRecordServiceImpl.handleVideoRecord(LearningRecordServiceImpl.java:236) ~[classes/:na]
	at com.tianji.learning.service.impl.LearningRecordServiceImpl.submitLearningRecord(LearningRecordServiceImpl.java:134) ~[classes/:na]
	

出错部分代码如下：

 Integer allSections = courseInfo.getSectionNum();   // 该课程所有小节数
// 判断该课程所有小节是否已学完
boolean allFinished = learningLesson.getLearnedSections() + 1 >= allSections;
// 更新课表信息：课表状态，已学小节数，最近学习小节id，最近学习时间
learningLessonService.lambdaUpdate()
    // 如果当前小节未学完，更新最近学习小节id和最近学习时间
    .set(LearningLesson::getLatestSectionId, learningLesson.getLatestSectionId() + 1)
    .set(LearningLesson::getLatestLearnTime, dto.getCommitTime())
    // 如果当前小姐已学完，更新已学小节数
    .set(LearningLesson::getLearnedSections, learningLesson.getLearnedSections())
    // 如果该课表所以小节已学完，则更新课表状态为已学完
    .set(allFinished, LearningLesson::getStatus, LessonStatus.FINISHED)
    // 首次学习需要将状态由未开始更新为学习中
    // .set(learningLesson.getLearnedSections() == 0 , LearningLesson::getStatus, LessonStatus.LEARNING)
    .set(learningLesson.getStatus() == LessonStatus.NOT_BEGIN, LearningLesson::getStatus, LessonStatus.LEARNING)
    .eq(LearningLesson::getId, learningLesson.getId())
    .update();

原因：在创建学习计划后，learned_sections字段由于未赋值为null，所以报了NPE

解决方法：在数据库表结构给该字段赋初值0。

5. Day05 问答系统

5.1 用户端分页查询评论时昵称错乱问题

原因：对于目标回复用户收集其target_user_id时和user_id混在一起，导致错误；

解决方案：将二者分开处理

 /**
     * 管理端分页查询回答或评论列表
     * @param pageQuery 分页参数
     * @return  分页列表
     */
    @Override
    public PageDTO pageAdmin(ReplyPageQuery pageQuery) {
        // 校验问题id和回答id是否都为空
        if (pageQuery.getAnswerId() == null && pageQuery.getQuestionId() == null) {
            throw new BadRequestException("查询参数错误");
        }
        // 分页查询回答或评论列表
        Page replyPage = this.lambdaQuery()
                // 如果传问题id就把问题id作查询条件
                .eq(pageQuery.getQuestionId() != null, InteractionReply::getQuestionId, pageQuery.getQuestionId())
                .eq(InteractionReply::getAnswerId, pageQuery.getAnswerId() == null ? 0L : pageQuery.getAnswerId())     // 字段默认值0
                .page(pageQuery.toMpPage(new OrderItem(DATA_FIELD_NAME_LIKED_TIME, false),
                        new OrderItem(DATA_FIELD_NAME_CREATE_TIME, true))); // 按照点赞次数降序排序降序，创建时间升序排序
        List records = replyPage.getRecords();
        if (CollUtil.isEmpty(records)) { // 查询不到，返回空集
            return PageDTO.of(replyPage, Collections.emptyList());
        }
        // 关联用户信息，先收集用户id，封装到map
        List userIds = new ArrayList();
        List targetUserIds = new ArrayList();   // 目标用户id
        List targetReplyIds = new ArrayList();   // 目标回复id
        for (InteractionReply reply : records) {
            if (!reply.getAnonymity()) { // 非匿名用户需要查询
                userIds.add(reply.getUserId());
                // userIds.add(reply.getTargetUserId());
            }
            // "target_user_id"字段默认值为0，查询评论时生效
            if (reply.getTargetUserId() != null && reply.getTargetUserId() > 0) {
                targetUserIds.add(reply.getTargetUserId());
            }
            // "target_reply_id"字段默认值为0，查询评论时生效
            if (reply.getTargetReplyId() != null && reply.getTargetReplyId() > 0) {
                targetReplyIds.add(reply.getTargetReplyId());
            }
        }
        // 查询目标回复列表并封装为Map
        Map targetReplyMap = new HashMap();
        // targetReplyIds不为空，去查询数据库
        if (!CollUtil.isEmpty(targetReplyIds)) {
            // 查询目标评论，并封装为Map
            List targetReplies = listByIds(targetReplyIds);
            targetReplyMap = targetReplies.stream().collect(Collectors.toMap(InteractionReply::getId, reply -> reply));
        }
        // 查询用户和目标回复用户并封装为Map
        Map userMap = getUserDTOMap(userIds);
        Map targetUserMap = getUserDTOMap(targetUserIds);
        // 保存结果
        List replyVOS = new ArrayList();
        for (InteractionReply reply : records) {
            ReplyVO replyVO = BeanUtil.toBean(reply, ReplyVO.class);
            UserDTO userDTO = userMap.getOrDefault(reply.getUserId(), null);
            // 如果当前回答或评论匿名，不进行赋值
            if (!replyVO.getAnonymity() && userDTO != null) {
                replyVO.setUserIcon(userDTO.getIcon()); // 回答人头像
                replyVO.setUserName(userDTO.getName()); // 回答人昵称
                replyVO.setUserType(userDTO.getType()); // 回答人类型
            }
            UserDTO targetUserDTO = targetUserMap.getOrDefault(reply.getTargetUserId(), null);
            InteractionReply targetReply = targetReplyMap.getOrDefault(reply.getTargetReplyId(), null);
            // 如果目标评论匿名，不进行赋值
            if (targetReply != null && !targetReply.getAnonymity() && targetUserDTO != null) {    // 目标回复非匿名才赋值
                replyVO.setTargetUserName(targetUserDTO.getName()); // 目标用户昵称
            }
            replyVOS.add(replyVO);
        }
        // 返回结果
        return PageDTO.of(replyPage, replyVOS);
    }

7. Day07 积分系统

7.1 mybatis-plus查询报错

错误信息：

Caused by: org.apache.ibatis.exceptions.PersistenceException: 
### Error querying database.  Cause: java.lang.IndexOutOfBoundsException: Index 2 out of bounds for length 2

相关代码：

    /**
     * 获取今日积分
     *
     * @return 今日积分列表
     */
    @Override
    public List getTodayPoints() {
        // 获取当前登录用户
        Long userId = UserContext.getUser();
        // 分类查询当前用户今日所得各类积分
        LocalDateTime now = LocalDateTime.now();
        LocalDateTime dayStartTime = DateUtils.getDayStartTime(now);    // 当前开始时间
        LocalDateTime dayEndTime = DateUtils.getDayEndTime(now);    // 当天结束时间
        QueryWrapper wrapper = new QueryWrapper();
        // 封装查询wrapper
        wrapper.select("type", "sum(points) as tmp")  // 查询类型和该类型积分数(使用临时变量暂存暂存BigDemical类型数据)
                .eq("user_id", userId) // 当前用户
                .between("create_time", dayStartTime, dayEndTime)  // 当天
                .groupBy("type");   // 根据类型分类
        wrapper.select("type", "sum(points) as userId");
        List records = this.list(wrapper);
        // 判空
        if (CollUtil.isEmpty(records)) {
            return Collections.emptyList();
        }
        // 封装到VO并返回
        List voList = records.stream().map(record -> {
            PointsStatisticsVO recordVO = new PointsStatisticsVO();
            recordVO.setPoints(record.getUserId().intValue()); // 该类型今日积分数，临时变量暂存
            recordVO.setType(record.getType().getDesc()); // 该类型名称
            recordVO.setMaxPoints(record.getType().getMaxPoints());   // 该类型上限积分数
            return recordVO;
        }).collect(Collectors.toList());
        return voList;
    }

原因：使用了PointsRecord存储查询结果，但该类没有构造器

解决方案：在PointsRecord添加@NoArgsConstructor

8. Day08 排行榜

8.1 xxl-job配置

原因：xxl-job在Springboot项目中集成后，需要手动新增相应的执行器和执行任务，不会自动新增，踩坑。

8.2 SpringBoot项目启动后立即停止

原因：SpringBoot启动后控制台无报错，但立即停止，缺少web依赖

解决方法：补充依赖spring-boot-starter-web如下

    org.springframework.boot
    spring-boot-starter-web

8.3 使用xxl-job迁移分表数据报错

错误信息：提示重复主键

Caused by: org.springframework.dao.DuplicateKeyException: com.tianji.learning.mapper.PointsRecordMapper.insert (batch index #1) failed. Cause: java.sql.BatchUpdateException: Duplicate entry '1773603384562077753' for key 'points_record.PRIMARY' ; Duplicate entry '1773603384562077753' for key 'points_record.PRIMARY'; 

原因：动态表名插件配置及使用错误

应该是先从当前赛季积分明细表分页查询数据后，更新动态表名，再插入到上赛季积分明细表

// 声明动态表名拦截器，使用拦截器插件
@Bean
public DynamicTableNameInnerInterceptor dynamicTableNameInnerInterceptor() {
    // 准备一个Map，用于存储TableNameHandler
    Map map = new HashMap(1);
    // 存入一个TableNameHandler，用来替换points_board表名称
    // 替换方式，就是从TableInfoContext中读取保存好的动态表名，判空是提高代码健壮性
    map.put("points_board", (sql, tableName) -> TableInfoContext.getInfo() == null ? tableName : TableInfoContext.getInfo());
    map.put("points_record", (sql, tableName) -> TableInfoContext.getInfo() == null ? tableName : TableInfoContext.getInfo());
    return new DynamicTableNameInnerInterceptor(map);
}

// 分页查询上赛季积分明细数据，先构建分页参数
PageQuery pageQuery = new PageQuery();
pageQuery.setPageNo(sharedIndex + 1); // 页码
pageQuery.setPageSize(50);    // 页面记录数
while (true) {
    log.debug("当前页:{}", pageQuery.getPageNo());
    TableInfoContext.setInfo(null); // 使用默认表名，points_record
    // 按照id升序查询
    Page recordPage = pointsRecordService.page(pageQuery.toMpPage("id",true));
    if (CollUtil.isEmpty(recordPage.getRecords())) {  // 结束循环
        break;
    }
    // 翻页，跳过N个页，N就是分片数量
    pageQuery.setPageNo(pageQuery.getPageNo() + shardTotal);   // 页码+total，跳过N页
    // 使用动态表名，points_record_5
    TableInfoContext.setInfo(targetTableName);
    // 持久化到db相应的赛季表中，批量新增
    pointsRecordService.saveBatch(recordPage.getRecords());
}

9. Day09 优惠券管理

9.1 新增优惠券mybatis错误

错误信息：

### The error may exist in com/tianji/promotion/mapper/CouponMapper.java (best guess)
### The error may involve com.tianji.promotion.mapper.CouponMapper.insert-Inline
### The error occurred while setting parameters
### SQL: INSERT INTO coupon  ( id, name,  discount_type, specific, discount_value, threshold_amount, max_discount_amount, obtain_way,       total_num,   user_limit,    creater, updater )  VALUES  ( ?, ?,  ?, ?, ?, ?, ?, ?,       ?,   ?,    ?, ? )
### Cause: java.sql.SQLSyntaxErrorException: You have an error in your SQL syntax; check the manual that corresponds to your MySQL server version for the right syntax to use near 'specific,
discount_value,
threshold_amount,
max_discount_amount,
obtain_way,

原因：specific是mysql关键字

@ApiModelProperty(value = "是否限定作用范围，false：不限定，true：限定。默认false")
private Boolean specific;

将Coupon实体类添加注解 @TableField注解

@ApiModelProperty(value = "是否限定作用范围，false：不限定，true：限定。默认false")
@TableField("`specific`")
private Boolean specific;

9.2 定时开始/结束发放优惠券遇到的bug

Bug1:Mybatis-Plus分页查询时碰到total有值但records为空

原因：Mybatis-Plus分页插件设置了maxLimit单页条数

// 分页插件配置
PaginationInnerInterceptor paginationInnerInterceptor = new PaginationInnerInterceptor(DbType.MYSQL);
paginationInnerInterceptor.setMaxLimit(200L);   // 单页分页条数限制(默认无限制)
interceptor.addInnerInterceptor(paginationInnerInterceptor);

方法：可以适当增大maxLimit或者修改代码：

// 分页插件配置
PaginationInnerInterceptor paginationInnerInterceptor = new PaginationInnerInterceptor(DbType.MYSQL);
paginationInnerInterceptor.setMaxLimit(200L);   // 单页分页条数限制(默认无限制)
paginationInnerInterceptor.setOverflow(true);   // 溢出总页数后是否进行处理(默认不处理)
interceptor.addInnerInterceptor(paginationInnerInterceptor);

注：

Mybatis-Plus分页参数说明如图所示：

参考链接：Mybatis-Plus分页插件参数说明

Bug2:xxl-job分片广播

原因：xxl-job结合分页时部分日志异常，如页号，推测可能局部配置异常或者内部bug，

	 /**
     * 定时开始发放优惠券
     * 利用XXL-JOB的数据分片功能实现
     */
	@XxlJob("couponIssueJobHandler")
    public void issueCoupon(LocalDateTime now, int shardTotal, int shardIndex) {
        log.info("开始执行定时开始发放优惠券任务...");
        PageQuery pageQuery = new PageQuery();
        pageQuery.setPageNo(shardIndex + 1);    // 页码（分片索引从0开始，页码从1开始）
        pageQuery.setPageSize(20);   // 页面大小，根据数据量动态调整
        while (true) {
            // 分页查询所有未开始的，发放开始时间早于当前时间的优惠券
            Page couponPage = couponService.lambdaQuery()
                    .eq(Coupon::getStatus, CouponStatus.UN_ISSUE)   // 查询未开始状态的
                    .le(Coupon::getIssueBeginTime, now)     // 发放开始时间早于当前时间
                    .page(pageQuery.toMpPage("id", true));// 根据id进行排序，避免重复处理数据
            List records = couponPage.getRecords();
            if (CollUtil.isEmpty(records)) { // 判空
                break;
            }
            // 更新优惠券状态
            records.stream().forEach(coupon -> coupon.setStatus(CouponStatus.ISSUING));
            // 批量更新优惠券
            couponService.updateBatchById(records);
            // 处理下一页数据
            if (couponPage.hasNext()) {
                // 翻页，数量为总分片数
                pageQuery.setPageNo(pageQuery.getPageNo() + shardTotal);
            } else {
                break;
            }
        }
        log.info("完成定时开始发放优惠券任务...");
    }

11. Day11领取优惠券优化

11.1 RabbitMQ交换机配置错误

错误信息如下：

16:47:54.429-[DESKTOP-CSPG5LG][sys]-- WARN 20360 --- [ntContainer#0-1] o.s.a.r.listener.BlockingQueueConsumer   : Failed to declare queue: coupon.receive.queue
16:47:54.430-[DESKTOP-CSPG5LG][sys]-- WARN 20360 --- [ntContainer#0-1] o.s.a.r.listener.BlockingQueueConsumer   : Queue declaration failed; retries left=1
org.springframework.amqp.rabbit.listener.BlockingQueueConsumer$DeclarationException: Failed to declare queue(s):[coupon.receive.queue]
   at org.springframework.amqp.rabbit.listener.BlockingQueueConsumer.attemptPassiveDeclarations(BlockingQueueConsumer.java:760) ~[spring-rabbit-2.4.6.jar:2.4.6]
   at org.springframework.amqp.rabbit.listener.BlockingQueueConsumer.passiveDeclarations(BlockingQueueConsumer.java:637) ~[spring-rabbit-2.4.6.jar:2.4.6]
   at org.springframework.amqp.rabbit.listener.BlockingQueueConsumer.start(BlockingQueueConsumer.java:624) ~[spring-rabbit-2.4.6.jar:2.4.6]
   at org.springframework.amqp.rabbit.listener.SimpleMessageListenerContainer$AsyncMessageProcessingConsumer.initialize(SimpleMessageListenerContainer.java:1376) ~[spring-rabbit-2.4.6.jar:2.4.6]
   at org.springframework.amqp.rabbit.listener.SimpleMessageListenerContainer$AsyncMessageProcessingConsumer.run(SimpleMessageListenerContainer.java:1221) ~[spring-rabbit-2.4.6.jar:2.4.6]
   at java.base/java.lang.Thread.run(Thread.java:834) ~[na:na]
Caused by: java.io.IOException: null
   at com.rabbitmq.client.impl.AMQChannel.wrap(AMQChannel.java:129) ~[amqp-client-5.14.2.jar:5.14.2]
   at com.rabbitmq.client.impl.AMQChannel.wrap(AMQChannel.java:125) ~[amqp-client-5.14.2.jar:5.14.2]
   at com.rabbitmq.client.impl.AMQChannel.exnWrappingRpc(AMQChannel.java:147) ~[amqp-client-5.14.2.jar:5.14.2]
   at com.rabbitmq.client.impl.ChannelN.queueDeclarePassive(ChannelN.java:1012) ~[amqp-client-5.14.2.jar:5.14.2]
   at com.rabbitmq.client.impl.ChannelN.queueDeclarePassive(ChannelN.java:46) ~[amqp-client-5.14.2.jar:5.14.2]
   at java.base/jdk.internal.reflect.NativeMethodAccessorImpl.invoke0(Native Method) ~[na:na]
   at java.base/jdk.internal.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:62) ~[na:na]
   at java.base/jdk.internal.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43) ~[na:na]
   at java.base/java.lang.reflect.Method.invoke(Method.java:566) ~[na:na]
   at org.springframework.amqp.rabbit.connection.CachingConnectionFactory$CachedChannelInvocationHandler.invoke(CachingConnectionFactory.java:1162) ~[spring-rabbit-2.4.6.jar:2.4.6]
   at com.sun.proxy.$Proxy223.queueDeclarePassive(Unknown Source) ~[na:na]
   at org.springframework.amqp.rabbit.listener.BlockingQueueConsumer.attemptPassiveDeclarations(BlockingQueueConsumer.java:738) ~[spring-rabbit-2.4.6.jar:2.4.6]
   ... 5 common frames omitted
Caused by: com.rabbitmq.client.ShutdownSignalException: channel error; protocol method: #method(reply-code=404, reply-text=NOT_FOUND - no queue 'coupon.receive.queue' in vhost '/tjxt', class-id=50, method-id=10)
   at com.rabbitmq.utility.ValueOrException.getValue(ValueOrException.java:66) ~[amqp-client-5.14.2.jar:5.14.2]
   at com.rabbitmq.utility.BlockingValueOrException.uninterruptibleGetValue(BlockingValueOrException.java:36) ~[amqp-client-5.14.2.jar:5.14.2]
   at com.rabbitmq.client.impl.AMQChannel$BlockingRpcContinuation.getReply(AMQChannel.java:502) ~[amqp-client-5.14.2.jar:5.14.2]
   at com.rabbitmq.client.impl.AMQChannel.privateRpc(AMQChannel.java:293) ~[amqp-client-5.14.2.jar:5.14.2]
   at com.rabbitmq.client.impl.AMQChannel.exnWrappingRpc(AMQChannel.java:141) ~[amqp-client-5.14.2.jar:5.14.2]
   ... 14 common frames omitted
Caused by: com.rabbitmq.client.ShutdownSignalException: channel error; protocol method: #method(reply-code=404, reply-text=NOT_FOUND - no queue 'coupon.receive.queue' in vhost '/tjxt', class-id=50, method-id=10)
   at com.rabbitmq.client.impl.ChannelN.asyncShutdown(ChannelN.java:517) ~[amqp-client-5.14.2.jar:5.14.2]
   at com.rabbitmq.client.impl.ChannelN.processAsync(ChannelN.java:341) ~[amqp-client-5.14.2.jar:5.14.2]
   at com.rabbitmq.client.impl.AMQChannel.handleCompleteInboundCommand(AMQChannel.java:182) ~[amqp-client-5.14.2.jar:5.14.2]
   at com.rabbitmq.client.impl.AMQChannel.handleFrame(AMQChannel.java:114) ~[amqp-client-5.14.2.jar:5.14.2]
   at com.rabbitmq.client.impl.AMQConnection.readFrame(AMQConnection.java:739) ~[amqp-client-5.14.2.jar:5.14.2]
   at com.rabbitmq.client.impl.AMQConnection.access$300(AMQConnection.java:47) ~[amqp-client-5.14.2.jar:5.14.2]
   at com.rabbitmq.client.impl.AMQConnection$MainLoop.run(AMQConnection.java:666) ~[amqp-client-5.14.2.jar:5.14.2]
   ... 1 common frames omitted
16:47:59.442-[DESKTOP-CSPG5LG][sys]-- WARN 20360 --- [ntContainer#0-1] o.s.a.r.listener.BlockingQueueConsumer   : Failed to declare queue: coupon.receive.queue
16:47:59.444-[DESKTOP-CSPG5LG][sys]--ERROR 20360 --- [ntContainer#0-1] o.s.a.r.l.SimpleMessageListenerContainer : Consumer threw missing queues exception, fatal=true
org.springframework.amqp.rabbit.listener.QueuesNotAvailableException: Cannot prepare queue for listener. Either the queue doesn't exist or the broker will not allow us to use it.
   at org.springframework.amqp.rabbit.listener.BlockingQueueConsumer.handleDeclarationException(BlockingQueueConsumer.java:710) ~[spring-rabbit-2.4.6.jar:2.4.6]
   at org.springframework.amqp.rabbit.listener.BlockingQueueConsumer.passiveDeclarations(BlockingQueueConsumer.java:644) ~[spring-rabbit-2.4.6.jar:2.4.6]
   at org.springframework.amqp.rabbit.listener.BlockingQueueConsumer.start(BlockingQueueConsumer.java:624) ~[spring-rabbit-2.4.6.jar:2.4.6]
   at org.springframework.amqp.rabbit.listener.SimpleMessageListenerContainer$AsyncMessageProcessingConsumer.initialize(SimpleMessageListenerContainer.java:1376) ~[spring-rabbit-2.4.6.jar:2.4.6]
   at org.springframework.amqp.rabbit.listener.SimpleMessageListenerContainer$AsyncMessageProcessingConsumer.run(SimpleMessageListenerContainer.java:1221) ~[spring-rabbit-2.4.6.jar:2.4.6]
   at java.base/java.lang.Thread.run(Thread.java:834) ~[na:na]
Caused by: org.springframework.amqp.rabbit.listener.BlockingQueueConsumer$DeclarationException: Failed to declare queue(s):[coupon.receive.queue]

原因：交换机类型错误，代码里写的是topic，mq里的是direct

/**
 * 更新优惠券已发放数量，新增用户券
 * @param uc   这里需要用到优惠券id和用户id
 */
@RabbitListener(bindings = @QueueBinding(
        value = @Queue(name = "coupon.receive.queue", durable = "true"),
        exchange = @Exchange(name = MqConstants.Exchange.PROMOTION_EXCHANGE,type = ExchangeTypes.TOPIC),
        key = MqConstants.Key.COUPON_RECEIVE
))
public void listenCouponReceiveMessage(UserCouponDTO uc){
    // 更新优惠券已发放数量，新增用户券
    userCouponService.checkAndCreateUserCoupon(uc);
}

解决方法：删掉现有MqConstants.Exchange.PROMOTION_EXCHANGE交换机，重新创建并绑定消息队列

coupon.receive.queue

11.2 Redis更新优惠券已发放数量的并发问题

问题描述及相关代码：

兑换码领券 UserCouponRedissonMQServiceImpl.exchangeCoupon接口， 更新Redis中指定优惠券的已发放数量的代码如下，在压力测试时会出现数据脏读问题，如领了3张券，issueNum只加了1

// 更新优惠券库的已发放数量+1
redisTemplate.opsForHash().put(PromotionConstants.COUPON_CACHE_KEY_PREFIX + id,
        "issueNum", String.valueOf(coupon.getIssueNum() + 1));

原因：并发线程角度时数据脏读问题

解决方法，修改代码：

// 更新优惠券的已发放数量+1
redisTemplate.opsForHash().increment(PromotionConstants.COUPON_CACHE_KEY_PREFIX + couponId,
        "issueNum", 1);