Failed to load driver class com.mysql.cj.jdbc.Driver

Question

• mysql 5.7
• mapper 4.1.5
• mysql-connector-java 5.1.48

写完testController后，mvn clean install内的test报错，内容是找不到 com.mysql.cj.jdbc.Driver
但我的版本及配置多次检查后，没有写过任何com.mysql.cj.jdbc.Driver的信息，这是为何呢。。。

Answer 1

大目 2019-10-28 23:58:36

您好，我这边试了很久，一直没有能够复现：

依赖：

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<dependency>     <groupId>mysql</groupId>     <artifactId>mysql-connector-java</artifactId>     <scope>runtime</scope>     <version>5.1.47</version> </dependency>

配置：

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spring:   datasource:     url: jdbc:mysql://localhost:3306/user_center?useUnicode=true&characterEncoding=utf8&useSSL=false     username: root     password: root123     driver-class-name: com.mysql.jdbc.Driver

能否帮忙把代码托管到GitHub或者Gitee，我来看看哈。

另外，不建议用Spring Boot 2.2版本进行测试。原因有2：

1. 2.2.0版本和课上的2.1.5版本有一定差异，容易采坑。不说别的，数据源的配置就不一样哈

2. Spring Cloud Alibaba和Spring Boot有一定的版本映射关系，在4-2节有详解。目前即使最新的Spring Cloud Alibaba 2.1.0，也只支持Spring Boot 2.1.x

建议严格按照课上选择的版本玩哦，在最近（双十一之前），课程就会更新到最新的版本，并且未来也会持续更新。帮助大家避免采坑的哈。

• 提问者 ahak #1

  #    hikari:
  #      username: 123
  #      password: 123
  #      # >= 6.x com.mysql.cj.jdbc.Driver
  #      # <= 5.x com.mysql.jdbc.Driver
  #      driver-class-name: com.mysql.jdbc.Driver
  
  
  
  是这组配置，使用hikari配置时候有问题（后面我贴的配置是我google后注释了hikari），目前不解的是hikari的。感谢老师深夜回复（太晚了没深究hikari的版本、特性、是什么，明天看看）

• 提问者 ahak #2

  我下载了hikari的sourceCode，从配置到报错逐层debug，貌似某一层级是根据com.mysql.cj.jdbc.Driver 这个格式去取配置的，配置的com.mysql.jdbc.Driver没有生效。我本地以及平时用mysql5.7比较多，故而为了后面考虑想使用5.7，查看了connector的best practice，貌似8.x是为了兼容mysql的8.x，推荐5.7mysql使用的依旧是5.1.x的connector

Answer 2

提问者 ahak 2019-10-28 23:13:58

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[ERROR] Tests run: 1, Failures: 0, Errors: 1, Skipped: 0, Time elapsed: 1.861 s <<< FAILURE! - in com.yaopig.usercenter.UserCenterApplicationTests [ERROR] contextLoads  Time elapsed: 0.001 s  <<< ERROR! java.lang.IllegalStateException: Failed to load ApplicationContext Caused by: org.springframework.beans.factory.UnsatisfiedDependencyException: Error creating bean with name 'testController': Unsatisfied dependency expressed through field 'userMapper'; nested exception is org.springframework.beans.factory.UnsatisfiedDependencyException: Error creating bean with name 'userMapper' defined in file [/private/var/www/http/user-center/target/classes/com/yaopig/usercenter/dao/user/UserMapper.class]: Unsatisfied dependency expressed through bean property 'sqlSessionFactory'; nested exception is org.springframework.beans.factory.UnsatisfiedDependencyException: Error creating bean with name 'sqlSessionFactory' defined in class path resource [tk/mybatis/mapper/autoconfigure/MapperAutoConfiguration.class]: Unsatisfied dependency expressed through method 'sqlSessionFactory' parameter 0; nested exception is org.springframework.beans.factory.BeanCreationException: Error creating bean with name 'dataSource' defined in class path resource [org/springframework/boot/autoconfigure/jdbc/DataSourceConfiguration$Hikari.class]: Bean instantiation via factory method failed; nested exception is org.springframework.beans.BeanInstantiationException: Failed to instantiate [com.zaxxer.hikari.HikariDataSource]: Factory method 'dataSource' threw exception; nested exception is org.springframework.boot.context.properties.bind.BindException: Failed to bind properties under '' to com.zaxxer.hikari.HikariDataSource Caused by: org.springframework.beans.factory.UnsatisfiedDependencyException: Error creating bean with name 'userMapper' defined in file [/private/var/www/http/user-center/target/classes/com/yaopig/usercenter/dao/user/UserMapper.class]: Unsatisfied dependency expressed through bean property 'sqlSessionFactory'; nested exception is org.springframework.beans.factory.UnsatisfiedDependencyException: Error creating bean with name 'sqlSessionFactory' defined in class path resource [tk/mybatis/mapper/autoconfigure/MapperAutoConfiguration.class]: Unsatisfied dependency expressed through method 'sqlSessionFactory' parameter 0; nested exception is org.springframework.beans.factory.BeanCreationException: Error creating bean with name 'dataSource' defined in class path resource [org/springframework/boot/autoconfigure/jdbc/DataSourceConfiguration$Hikari.class]: Bean instantiation via factory method failed; nested exception is org.springframework.beans.BeanInstantiationException: Failed to instantiate [com.zaxxer.hikari.HikariDataSource]: Factory method 'dataSource' threw exception; nested exception is org.springframework.boot.context.properties.bind.BindException: Failed to bind properties under '' to com.zaxxer.hikari.HikariDataSource Caused by: org.springframework.beans.factory.UnsatisfiedDependencyException: Error creating bean with name 'sqlSessionFactory' defined in class path resource [tk/mybatis/mapper/autoconfigure/MapperAutoConfiguration.class]: Unsatisfied dependency expressed through method 'sqlSessionFactory' parameter 0; nested exception is org.springframework.beans.factory.BeanCreationException: Error creating bean with name 'dataSource' defined in class path resource [org/springframework/boot/autoconfigure/jdbc/DataSourceConfiguration$Hikari.class]: Bean instantiation via factory method failed; nested exception is org.springframework.beans.BeanInstantiationException: Failed to instantiate [com.zaxxer.hikari.HikariDataSource]: Factory method 'dataSource' threw exception; nested exception is org.springframework.boot.context.properties.bind.BindException: Failed to bind properties under '' to com.zaxxer.hikari.HikariDataSource Caused by: org.springframework.beans.factory.BeanCreationException: Error creating bean with name 'dataSource' defined in class path resource [org/springframework/boot/autoconfigure/jdbc/DataSourceConfiguration$Hikari.class]: Bean instantiation via factory method failed; nested exception is org.springframework.beans.BeanInstantiationException: Failed to instantiate [com.zaxxer.hikari.HikariDataSource]: Factory method 'dataSource' threw exception; nested exception is org.springframework.boot.context.properties.bind.BindException: Failed to bind properties under '' to com.zaxxer.hikari.HikariDataSource Caused by: org.springframework.beans.BeanInstantiationException: Failed to instantiate [com.zaxxer.hikari.HikariDataSource]: Factory method 'dataSource' threw exception; nested exception is org.springframework.boot.context.properties.bind.BindException: Failed to bind properties under '' to com.zaxxer.hikari.HikariDataSource Caused by: org.springframework.boot.context.properties.bind.BindException: Failed to bind properties under '' to com.zaxxer.hikari.HikariDataSource Caused by: java.lang.IllegalStateException: Unable to set value for property driver-class-name Caused by: java.lang.reflect.InvocationTargetException Caused by: java.lang.RuntimeException: Failed to load driver class com.mysql.cj.jdbc.Driver in either of HikariConfig class loader or Thread context classloader

Answer 3

提问者 ahak 2019-10-28 23:11:37

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spring:   datasource:     url: jdbc:mysql://localhost:3306/user_center?useUnicode=true&characterEncoding=utf8&useSSL=false     username: 123     password: 123     driver-class-name: com.mysql.jdbc.Driver #    hikari: #      username: 123 #      password: 123 #      # >= 6.x com.mysql.cj.jdbc.Driver #      # <= 5.x com.mysql.jdbc.Driver #      driver-class-name: com.mysql.jdbc.Driver

替换调hikari后可以通过了。。难道是版本问题，5xx没有cj的不可以用hikari？

Answer 4

提问者 ahak 2019-10-28 23:06:56

报错的异常都集中在 hikari那里。感觉是DataSource这里不可以使用？

• 大目 #1

  帮忙贴出来哈，从报错的开始，一直复制到报错结束即可。

• 提问者 ahak 回复 大目 #2

  字数。。超了 ?

Answer 5

提问者 ahak 2019-10-28 23:05:58

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spring:   datasource:     url: jdbc:mysql://localhost:3306/user_center?useUnicode=true&characterEncoding=utf8&useSSL=false     hikari:       username: 123       password: 123       # >= 6.x com.mysql.cj.jdbc.Driver       # <= 5.x com.mysql.jdbc.Driver       driver-class-name: com.mysql.jdbc.Driver

Answer 6

提问者 ahak 2019-10-28 23:05:20

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<?xml version="1.0" encoding="UTF-8"?> <project xmlns="http://maven.apache.org/POM/4.0.0" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"          xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 https://maven.apache.org/xsd/maven-4.0.0.xsd">     <modelVersion>4.0.0</modelVersion>     <parent>         <groupId>org.springframework.boot</groupId>         <artifactId>spring-boot-starter-parent</artifactId>         <version>2.2.0.RELEASE</version>         <relativePath/> <!-- lookup parent from repository -->     </parent>     <groupId>com.yaopig</groupId>     <artifactId>user-center</artifactId>     <version>0.0.1-SNAPSHOT</version>     <name>user-center</name>     <description>aaa user-center</description>       <properties>         <java.version>1.8</java.version>     </properties>       <dependencies>         <dependency>             <groupId>org.springframework.boot</groupId>             <artifactId>spring-boot-starter-web</artifactId>         </dependency>           <dependency>             <groupId>tk.mybatis</groupId>             <artifactId>mapper-spring-boot-starter</artifactId>             <version>2.1.5</version>         </dependency>           <dependency>             <groupId>mysql</groupId>             <artifactId>mysql-connector-java</artifactId>             <version>5.1.48</version>         </dependency>           <dependency>             <groupId>org.springframework.boot</groupId>             <artifactId>spring-boot-starter-test</artifactId>             <scope>test</scope>             <exclusions>                 <exclusion>                     <groupId>org.junit.vintage</groupId>                     <artifactId>junit-vintage-engine</artifactId>                 </exclusion>             </exclusions>         </dependency>     </dependencies>       <build>         <plugins>             <plugin>                 <groupId>org.springframework.boot</groupId>                 <artifactId>spring-boot-maven-plugin</artifactId>             </plugin>               <plugin>                 <groupId>org.mybatis.generator</groupId>                 <artifactId>mybatis-generator-maven-plugin</artifactId>                 <version>1.3.6</version>                 <configuration>                     <configurationFile>                         ${basedir}/src/main/resources/generator/generatorConfig.xml                     </configurationFile>                     <overwrite>true</overwrite>                     <verbose>true</verbose>                 </configuration>                 <dependencies>                     <dependency>                         <groupId>mysql</groupId>                         <artifactId>mysql-connector-java</artifactId>                         <version>5.1.48</version>                     </dependency>                     <dependency>                         <groupId>tk.mybatis</groupId>                         <artifactId>mapper</artifactId>                         <version>4.1.5</version>                     </dependency>                 </dependencies>             </plugin>           </plugins>     </build>   </project>

Answer 7

大目 2019-10-28 23:04:30

您好，帮忙提供下：

1. 项目的pom.xml

2. 项目的配置文件application.yml

3. 完整的异常栈