jdbc驱动包版本太高了，用5.1.*的

问题一：

Failed to execute goal org.mybatis.generator:mybatis-generator-maven-plugin:1.3.5:generate (default-cli) on project miaosha: Unknown system variable 'query_cache_size'

解决一：

如果出现此问题，说明同行者你是在此课程出来后很久才开始学习！

所以只需要改变mysql的版本就可以了，我改成了8.0.27版本

<groupId>mysql</groupId>
  <artifactId>mysql-connector-java</artifactId>
  <version>8.0.27</version>
</dependency>

问题二：

 Failed to execute goal org.mybatis.generator:mybatis-generator-maven-plugin:1.3.5:generate (default-cli) on project miaosha: Execution default-cli of goal org.mybatis.generator:mybatis-generator-maven-plugin:1.3.5:generate failed: An API incompatibility was encountered while executing org.mybatis.generator:mybatis-generator-maven-plugin:1.3.5:generate: java.lang.NoSuchMethodError: org.mybatis.generator.internal.ObjectFactory.addResourceClassLoader(Ljava/lang/ClassLoader;)V

解决二：

将plugins中的下面的依赖，先拿到plugins外面一层，刷新maven，然后放回去，即可解决

<dependency>
  <groupId>org.mybatis.generator</groupId>
  <artifactId>mybatis-generator-core</artifactId>
  <version>1.3.5</version>
</dependency>

求解决

我也遇见了相同的问题，请问您如何解决的

路径错了 src 不是scr 你仔细看看你的报错原因 在pom文件改

COM.mysql.cj.jdbc.Driver我改的是这样的

可能你的MySQL版本过高，但是驱动是低版本的

C:\Users\Administrator\.jdks\openjdk-16.0.2\bin\java.exe "-javaagent:D:\IntelliJ IDEA Community Edition 2021.1.2\lib\idea_rt.jar=5871:D:\IntelliJ IDEA Community Edition 2021.1.2\bin" -Dfile.encoding=UTF-8 -classpath F:\glshop\target\classes;C:\Users\Administrator\.m2\repository\org\springframework\boot\spring-boot-starter-web\2.5.5\spring-boot-starter-web-2.5.5.jar;C:\Users\Administrator\.m2\repository\org\springframework\boot\spring-boot-starter\2.5.5\spring-boot-starter-2.5.5.jar;C:\Users\Administrator\.m2\repository\org\springframework\boot\spring-boot\2.5.5\spring-boot-2.5.5.jar;C:\Users\Administrator\.m2\repository\org\springframework\boot\spring-boot-starter-logging\2.5.5\spring-boot-starter-logging-2.5.5.jar;C:\Users\Administrator\.m2\repository\ch\qos\logback\logback-classic\1.2.6\logback-classic-1.2.6.jar;C:\Users\Administrator\.m2\repository\ch\qos\logback\logback-core\1.2.6\logback-core-1.2.6.jar;C:\Users\Administrator\.m2\repository\org\apache\logging\log4j\log4j-to-slf4j\2.14.1\log4j-to-slf4j-2.14.1.jar;C:\Users\Administrator\.m2\repository\org\apache\logging\log4j\log4j-api\2.14.1\log4j-api-2.14.1.jar;C:\Users\Administrator\.m2\repository\org\slf4j\jul-to-slf4j\1.7.32\jul-to-slf4j-1.7.32.jar;C:\Users\Administrator\.m2\repository\jakarta\annotation\jakarta.annotation-api\1.3.5\jakarta.annotation-api-1.3.5.jar;C:\Users\Administrator\.m2\repository\org\springframework\spring-core\5.3.10\spring-core-5.3.10.jar;C:\Users\Administrator\.m2\repository\org\springframework\spring-jcl\5.3.10\spring-jcl-5.3.10.jar;C:\Users\Administrator\.m2\repository\org\yaml\snakeyaml\1.28\snakeyaml-1.28.jar;C:\Users\Administrator\.m2\repository\org\springframework\boot\spring-boot-starter-json\2.5.5\spring-boot-starter-json-2.5.5.jar;C:\Users\Administrator\.m2\repository\com\fasterxml\jackson\core\jackson-databind\2.12.5\jackson-databind-2.12.5.jar;C:\Users\Administrator\.m2\repository\com\fasterxml\jackson\core\jackson-annotations\2.12.5\jackson-annotations-2.12.5.jar;C:\Users\Administrator\.m2\repository\com\fasterxml\jackson\core\jackson-core\2.12.5\jackson-core-2.12.5.jar;C:\Users\Administrator\.m2\repository\com\fasterxml\jackson\datatype\jackson-datatype-jdk8\2.12.5\jackson-datatype-jdk8-2.12.5.jar;C:\Users\Administrator\.m2\repository\com\fasterxml\jackson\datatype\jackson-datatype-jsr310\2.12.5\jackson-datatype-jsr310-2.12.5.jar;C:\Users\Administrator\.m2\repository\com\fasterxml\jackson\module\jackson-module-parameter-names\2.12.5\jackson-module-parameter-names-2.12.5.jar;C:\Users\Administrator\.m2\repository\org\springframework\boot\spring-boot-starter-tomcat\2.5.5\spring-boot-starter-tomcat-2.5.5.jar;C:\Users\Administrator\.m2\repository\org\apache\tomcat\embed\tomcat-embed-core\9.0.53\tomcat-embed-core-9.0.53.jar;C:\Users\Administrator\.m2\repository\org\apache\tomcat\embed\tomcat-embed-el\9.0.53\tomcat-embed-el-9.0.53.jar;C:\Users\Administrator\.m2\repository\org\apache\tomcat\embed\tomcat-embed-websocket\9.0.53\tomcat-embed-websocket-9.0.53.jar;C:\Users\Administrator\.m2\repository\org\springframework\spring-web\5.3.10\spring-web-5.3.10.jar;C:\Users\Administrator\.m2\repository\org\springframework\spring-beans\5.3.10\spring-beans-5.3.10.jar;C:\Users\Administrator\.m2\repository\org\springframework\spring-webmvc\5.3.10\spring-webmvc-5.3.10.jar;C:\Users\Administrator\.m2\repository\org\springframework\spring-aop\5.3.10\spring-aop-5.3.10.jar;C:\Users\Administrator\.m2\repository\org\springframework\spring-context\5.3.10\spring-context-5.3.10.jar;C:\Users\Administrator\.m2\repository\org\springframework\spring-expression\5.3.10\spring-expression-5.3.10.jar;C:\Users\Administrator\.m2\repository\mysql\mysql-connector-java\8.0.25\mysql-connector-java-8.0.25.jar;C:\Users\Administrator\.m2\repository\com\alibaba\druid-spring-boot-starter\1.1.13\druid-spring-boot-starter-1.1.13.jar;C:\Users\Administrator\.m2\repository\com\alibaba\druid\1.1.13\druid-1.1.13.jar;C:\Users\Administrator\.m2\repository\org\slf4j\slf4j-api\1.7.32\slf4j-api-1.7.32.jar;C:\Users\Administrator\.m2\repository\org\springframework\boot\spring-boot-autoconfigure\2.5.5\spring-boot-autoconfigure-2.5.5.jar;C:\Users\Administrator\.m2\repository\com\alibaba\fastjson\1.2.47\fastjson-1.2.47.jar;C:\Users\Administrator\.m2\repository\org\mybatis\spring\boot\mybatis-spring-boot-starter\1.3.2\mybatis-spring-boot-starter-1.3.2.jar;C:\Users\Administrator\.m2\repository\org\springframework\boot\spring-boot-starter-jdbc\2.5.5\spring-boot-starter-jdbc-2.5.5.jar;C:\Users\Administrator\.m2\repository\com\zaxxer\HikariCP\4.0.3\HikariCP-4.0.3.jar;C:\Users\Administrator\.m2\repository\org\springframework\spring-jdbc\5.3.10\spring-jdbc-5.3.10.jar;C:\Users\Administrator\.m2\repository\org\springframework\spring-tx\5.3.10\spring-tx-5.3.10.jar;C:\Users\Administrator\.m2\repository\org\mybatis\spring\boot\mybatis-spring-boot-autoconfigure\1.3.2\mybatis-spring-boot-autoconfigure-1.3.2.jar;C:\Users\Administrator\.m2\repository\org\mybatis\mybatis\3.4.6\mybatis-3.4.6.jar;C:\Users\Administrator\.m2\repository\org\mybatis\mybatis-spring\1.3.2\mybatis-spring-1.3.2.jar;C:\Users\Administrator\.m2\repository\org\mybatis\generator\mybatis-generator-core\1.3.5\mybatis-generator-core-1.3.5.jar com.glshopproject.App

Hello World!

  .   ____          _            __ _ _

 /\\ / ___'_ __ _ _(_)_ __  __ _ \ \ \ \

( ( )\___ | '_ | '_| | '_ \/ _` | \ \ \ \

 \\/  ___)| |_)| | | | | || (_| |  ) ) ) )

  '  |____| .__|_| |_|_| |_\__, | / / / /

 =========|_|==============|___/=/_/_/_/

 :: Spring Boot ::                (v2.5.5)

2021-10-14 01:16:00.795  INFO 2608 --- [           main] com.glshopproject.App                    : Starting App using Java 16.0.2 on PC-20210817LEZZ with PID 2608 (F:\glshop\target\classes started by Administrator in F:\glshop)

2021-10-14 01:16:00.798  INFO 2608 --- [           main] com.glshopproject.App                    : No active profile set, falling back to default profiles: default

2021-10-14 01:16:01.604  WARN 2608 --- [           main] o.m.s.mapper.ClassPathMapperScanner      : No MyBatis mapper was found in '[com.glshopproject]' package. Please check your configuration.

2021-10-14 01:16:02.135  INFO 2608 --- [           main] o.s.b.w.embedded.tomcat.TomcatWebServer  : Tomcat initialized with port(s): 8090 (http)

2021-10-14 01:16:02.146  INFO 2608 --- [           main] o.apache.catalina.core.StandardService   : Starting service [Tomcat]

2021-10-14 01:16:02.146  INFO 2608 --- [           main] org.apache.catalina.core.StandardEngine  : Starting Servlet engine: [Apache Tomcat/9.0.53]

2021-10-14 01:16:02.215  INFO 2608 --- [           main] o.a.c.c.C.[Tomcat].[localhost].[/]       : Initializing Spring embedded WebApplicationContext

2021-10-14 01:16:02.215  INFO 2608 --- [           main] w.s.c.ServletWebServerApplicationContext : Root WebApplicationContext: initialization completed in 1286 ms

2021-10-14 01:16:02.259  WARN 2608 --- [           main] ConfigServletWebServerApplicationContext : Exception encountered during context initialization - cancelling refresh attempt: org.springframework.beans.factory.UnsatisfiedDependencyException: Error creating bean with name 'app': Unsatisfied dependency expressed through field 'userDOMapper'; nested exception is org.springframework.beans.factory.NoSuchBeanDefinitionException: No qualifying bean of type 'com.glshopproject.dao.UserDOMapper' available: expected at least 1 bean which qualifies as autowire candidate. Dependency annotations: {@org.springframework.beans.factory.annotation.Autowired(required=true)}

2021-10-14 01:16:02.263  INFO 2608 --- [           main] o.apache.catalina.core.StandardService   : Stopping service [Tomcat]

2021-10-14 01:16:02.323  INFO 2608 --- [           main] ConditionEvaluationReportLoggingListener : 

Error starting ApplicationContext. To display the conditions report re-run your application with 'debug' enabled.

2021-10-14 01:16:02.342 ERROR 2608 --- [           main] o.s.b.d.LoggingFailureAnalysisReporter   : 

***************************

APPLICATION FAILED TO START

***************************

Description:

Field userDOMapper in com.glshopproject.App required a bean of type 'com.glshopproject.dao.UserDOMapper' that could not be found.

The injection point has the following annotations:

- @org.springframework.beans.factory.annotation.Autowired(required=true)

Action:

Consider defining a bean of type 'com.glshopproject.dao.UserDOMapper' in your configuration.

Process finished with exit code 1

application.properties文件有单词拼错，低级错误，嘤嘤嘤

解决了:

spring.datasource.url=jdbc:mysql://127.0.0.1:3306/miaosha

mysql后面少了个:

你这类名写的是camelCase的，在代码里引入怎么变成全大写了

是不是连接mysql的用户名和密码不对哦?

注解一般是相应的依赖有问题，你看看pom.xml文件里面的依赖是不是有问题

已解决   

我也是

怎么解决的

此问题已解决。

pom.xml下面添加如下插件

<plugin>
    <groupId>org.apache.maven.plugins</groupId>
    <artifactId>maven-resources-plugin</artifactId>
    <version>2.7</version>
    <configuration>
        <!-- 在构建路径中 指定源文件编译的字符编码 -->
        <encoding>UTF-8</encoding>
    </configuration>
</plugin>

看一下相应的xml文件相应的方法是不是有问题，如果是自动生成的话那就应该没有什么问题