无法从 HikariConfig 加载驱动程序 class com.mysql.cj.jdbc.Driver

Question

我是java/spring的新手，正在尝试将我的项目连接到mysql数据库，但在运行应用程序时出现此错误：

2022-12-31T19:24:59.857+01:00 ERROR 76110 --- [           main] com.zaxxer.hikari.HikariConfig           : Failed to load driver class com.mysql.cj.jdbc.Driver from HikariConfig class classloader jdk.internal.loader.ClassLoaders$AppClassLoader@251a69d7

Error starting ApplicationContext. To display the condition evaluation report re-run your application with 'debug' enabled.
2022-12-31T19:24:59.871+01:00 ERROR 76110 --- [           main] o.s.boot.SpringApplication               : Application run failed

org.springframework.beans.factory.UnsatisfiedDependencyException: Error creating bean with name 'dataSourceScriptDatabaseInitializer' defined in class path resource [org/springframework/boot/autoconfigure/sql/init/DataSourceInitializationConfiguration.class]: Unsatisfied dependency expressed through method 'dataSourceScriptDatabaseInitializer' parameter 0: Error creating bean with name 'dataSource' defined in class path resource [org/springframework/boot/autoconfigure/jdbc/DataSourceConfiguration$Hikari.class]: Failed to instantiate [com.zaxxer.hikari.HikariDataSource]: Factory method 'dataSource' threw exception with message: Failed to load driver class com.mysql.cj.jdbc.Driver in either of HikariConfig class loader or Thread context classloader
    at org.springframework.beans.factory.support.ConstructorResolver.createArgumentArray(ConstructorResolver.java:798) ~[spring-beans-6.0.3.jar:6.0.3]
    at org.springframework.beans.factory.support.ConstructorResolver.instantiateUsingFactoryMethod(ConstructorResolver.java:548) ~[spring-beans-6.0.3.jar:6.0.3]
    at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.instantiateUsingFactoryMethod(AbstractAutowireCapableBeanFactory.java:1324) ~[spring-beans-6.0.3.jar:6.0.3]
    at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.createBeanInstance(AbstractAutowireCapableBeanFactory.java:1161) ~[spring-beans-6.0.3.jar:6.0.3]
    at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.doCreateBean(AbstractAutowireCapableBeanFactory.java:561) ~[spring-beans-6.0.3.jar:6.0.3]
    at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.createBean(AbstractAutowireCapableBeanFactory.java:521) ~[spring-beans-6.0.3.jar:6.0.3]
    at org.springframework.beans.factory.support.AbstractBeanFactory.lambda$doGetBean$0(AbstractBeanFactory.java:326) ~[spring-beans-6.0.3.jar:6.0.3]
    at org.springframework.beans.factory.support.DefaultSingletonBeanRegistry.getSingleton(DefaultSingletonBeanRegistry.java:234) ~[spring-beans-6.0.3.jar:6.0.3]
    at org.springframework.beans.factory.support.AbstractBeanFactory.doGetBean(AbstractBeanFactory.java:324) ~[spring-beans-6.0.3.jar:6.0.3]
    at org.springframework.beans.factory.support.AbstractBeanFactory.getBean(AbstractBeanFactory.java:200) ~[spring-beans-6.0.3.jar:6.0.3]
    at org.springframework.beans.factory.support.AbstractBeanFactory.doGetBean(AbstractBeanFactory.java:313) ~[spring-beans-6.0.3.jar:6.0.3]
    at org.springframework.beans.factory.support.AbstractBeanFactory.getBean(AbstractBeanFactory.java:200) ~[spring-beans-6.0.3.jar:6.0.3]
    at org.springframework.context.support.AbstractApplicationContext.getBean(AbstractApplicationContext.java:1130) ~[spring-context-6.0.3.jar:6.0.3]
    at org.springframework.context.support.AbstractApplicationContext.finishBeanFactoryInitialization(AbstractApplicationContext.java:905) ~[spring-context-6.0.3.jar:6.0.3]
    at org.springframework.context.support.AbstractApplicationContext.refresh(AbstractApplicationContext.java:584) ~[spring-context-6.0.3.jar:6.0.3]
    at org.springframework.boot.web.servlet.context.ServletWebServerApplicationContext.refresh(ServletWebServerApplicationContext.java:146) ~[spring-boot-3.0.1.jar:3.0.1]
    at org.springframework.boot.SpringApplication.refresh(SpringApplication.java:730) ~[spring-boot-3.0.1.jar:3.0.1]
    at org.springframework.boot.SpringApplication.refreshContext(SpringApplication.java:432) ~[spring-boot-3.0.1.jar:3.0.1]
    at org.springframework.boot.SpringApplication.run(SpringApplication.java:308) ~[spring-boot-3.0.1.jar:3.0.1]
    at org.springframework.boot.SpringApplication.run(SpringApplication.java:1302) ~[spring-boot-3.0.1.jar:3.0.1]
    at org.springframework.boot.SpringApplication.run(SpringApplication.java:1291) ~[spring-boot-3.0.1.jar:3.0.1]
    at com.example.java2.Java2Application.main(Java2Application.java:12) ~[classes/:na]
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]: Failed to instantiate [com.zaxxer.hikari.HikariDataSource]: Factory method 'dataSource' threw exception with message: Failed to load driver class com.mysql.cj.jdbc.Driver in either of HikariConfig class loader or Thread context classloader
    at org.springframework.beans.factory.support.ConstructorResolver.instantiate(ConstructorResolver.java:657) ~[spring-beans-6.0.3.jar:6.0.3]
    at org.springframework.beans.factory.support.ConstructorResolver.instantiateUsingFactoryMethod(ConstructorResolver.java:645) ~[spring-beans-6.0.3.jar:6.0.3]
    at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.instantiateUsingFactoryMethod(AbstractAutowireCapableBeanFactory.java:1324) ~[spring-beans-6.0.3.jar:6.0.3]
    at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.createBeanInstance(AbstractAutowireCapableBeanFactory.java:1161) ~[spring-beans-6.0.3.jar:6.0.3]
    at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.doCreateBean(AbstractAutowireCapableBeanFactory.java:561) ~[spring-beans-6.0.3.jar:6.0.3]
    at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.createBean(AbstractAutowireCapableBeanFactory.java:521) ~[spring-beans-6.0.3.jar:6.0.3]
    at org.springframework.beans.factory.support.AbstractBeanFactory.lambda$doGetBean$0(AbstractBeanFactory.java:326) ~[spring-beans-6.0.3.jar:6.0.3]
    at org.springframework.beans.factory.support.DefaultSingletonBeanRegistry.getSingleton(DefaultSingletonBeanRegistry.java:234) ~[spring-beans-6.0.3.jar:6.0.3]
    at org.springframework.beans.factory.support.AbstractBeanFactory.doGetBean(AbstractBeanFactory.java:324) ~[spring-beans-6.0.3.jar:6.0.3]
    at org.springframework.beans.factory.support.AbstractBeanFactory.getBean(AbstractBeanFactory.java:200) ~[spring-beans-6.0.3.jar:6.0.3]
    at org.springframework.beans.factory.config.DependencyDescriptor.resolveCandidate(DependencyDescriptor.java:254) ~[spring-beans-6.0.3.jar:6.0.3]
    at org.springframework.beans.factory.support.DefaultListableBeanFactory.doResolveDependency(DefaultListableBeanFactory.java:1405) ~[spring-beans-6.0.3.jar:6.0.3]
    at org.springframework.beans.factory.support.DefaultListableBeanFactory.resolveDependency(DefaultListableBeanFactory.java:1325) ~[spring-beans-6.0.3.jar:6.0.3]
    at org.springframework.beans.factory.support.ConstructorResolver.resolveAutowiredArgument(ConstructorResolver.java:885) ~[spring-beans-6.0.3.jar:6.0.3]
    at org.springframework.beans.factory.support.ConstructorResolver.createArgumentArray(ConstructorResolver.java:789) ~[spring-beans-6.0.3.jar:6.0.3]
    ... 21 common frames omitted
Caused by: org.springframework.beans.BeanInstantiationException: Failed to instantiate [com.zaxxer.hikari.HikariDataSource]: Factory method 'dataSource' threw exception with message: Failed to load driver class com.mysql.cj.jdbc.Driver in either of HikariConfig class loader or Thread context classloader
    at org.springframework.beans.factory.support.SimpleInstantiationStrategy.instantiate(SimpleInstantiationStrategy.java:171) ~[spring-beans-6.0.3.jar:6.0.3]
    at org.springframework.beans.factory.support.ConstructorResolver.instantiate(ConstructorResolver.java:653) ~[spring-beans-6.0.3.jar:6.0.3]
    ... 35 common frames omitted
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
    at com.zaxxer.hikari.HikariConfig.setDriverClassName(HikariConfig.java:488) ~[HikariCP-5.0.1.jar:na]
    at org.springframework.boot.jdbc.DataSourceBuilder$MappedDataSourceProperty.set(DataSourceBuilder.java:479) ~[spring-boot-3.0.1.jar:3.0.1]
    at org.springframework.boot.jdbc.DataSourceBuilder$MappedDataSourceProperties.set(DataSourceBuilder.java:373) ~[spring-boot-3.0.1.jar:3.0.1]
    at org.springframework.boot.jdbc.DataSourceBuilder.build(DataSourceBuilder.java:183) ~[spring-boot-3.0.1.jar:3.0.1]
    at org.springframework.boot.autoconfigure.jdbc.DataSourceConfiguration.createDataSource(DataSourceConfiguration.java:48) ~[spring-boot-autoconfigure-3.0.1.jar:3.0.1]
    at org.springframework.boot.autoconfigure.jdbc.DataSourceConfiguration$Hikari.dataSource(DataSourceConfiguration.java:90) ~[spring-boot-autoconfigure-3.0.1.jar:3.0.1]
    at java.base/jdk.internal.reflect.DirectMethodHandleAccessor.invoke(DirectMethodHandleAccessor.java:104) ~[na:na]
    at java.base/java.lang.reflect.Method.invoke(Method.java:578) ~[na:na]
    at org.springframework.beans.factory.support.SimpleInstantiationStrategy.instantiate(SimpleInstantiationStrategy.java:139) ~[spring-beans-6.0.3.jar:6.0.3]
    ... 36 common frames omitted


Process finished with exit code 1

解决方案（ 1 、 2 ）似乎都不起作用。 这是我的applications.properties文件：

spring.datasource.url=jdbc:mysql://localhost:3306/java
spring.datasource.username=root
spring.datasource.password=...
spring.jpa.hibernate.ddl-auto=create-drop
spring.jpa.show-sql=true
spring.jpa.properties.hibernate.dialect=org.hibernate.dialect.MySQL8InnoDBDialect
spring.jpa.properties.hibernate.format_sql=true

这是我的pom.xml文件：

<?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>3.0.1</version>
        <relativePath/> <!-- lookup parent from repository -->
    </parent>
    <groupId>com.example</groupId>
    <artifactId>java2</artifactId>
    <version>0.0.1-SNAPSHOT</version>
    <name>java2</name>
    <description>java2</description>
    <properties>
        <java.version>19</java.version>
    </properties>
    <dependencies>
        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-web</artifactId>
        </dependency>

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

        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-test</artifactId>
            <scope>test</scope>
        </dependency>
        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-data-jpa</artifactId>
        </dependency>
    </dependencies>

    <build>
        <plugins>
            <plugin>
                <groupId>org.springframework.boot</groupId>
                <artifactId>spring-boot-maven-plugin</artifactId>
            </plugin>
        </plugins>
    </build>

</project>

我正在使用Intellij IDEA Ultimate ，安装了jakarta plugin并且数据库工具已经连接到mysql数据库，但我无法让它与我的spring app一起使用。

Answer 1

我认为你的方言是错误的。 删除您拥有的方言配置并尝试使用这些配置：spring.datasource.driver-class-name=com.mysql.cj.jdbc.Driver spring.jpa.database-platform=org.8839838789930

Answer 2

此错误消息表示应用程序未找到 MySQL JDBC 驱动程序。

要修复此错误，您需要确保 MySQL JDBC 驱动程序包含在项目的类路径中。 您可以通过将驱动程序作为依赖项添加到项目的构建文件（如果您使用的是 Maven，则为 pom.xml），然后重建项目。

例如，如果您使用的是 Maven，则可以将以下依赖项添加到 pom.xml 文件中：

<dependency>
  <groupId>mysql</groupId>
  <artifactId>mysql-connector-java</artifactId>
  <version>8.0.23</version>

然后，通过运行 mvn clean install 或使用构建工具的等效命令来重建项目。

重建项目后，MySQL JDBC 驱动程序应该在类路径中可用，应用程序应该可以加载它。

如果问题仍然存在，仔细检查数据库连接的配置可能会有所帮助，包括 JDBC URL、用户名和密码。 确保这些值正确并且数据库正在运行并且可以从应用程序访问。