Spring Boot启动报错：无法加载com.mysql.cj.jdbc.Driver驱动类

我正在学习Spring，用Netbeans构建项目，通过Spring Initializr初始化了所有文件，但运行项目时出现错误：Cannot load driver class: com.mysql.cj.jdbc.Driver。已配置驱动、在pom.xml中添加依赖并设置项目属性，但问题仍存在，求排查。

错误信息 #

Error starting ApplicationContext. To display the conditions report re-run your application with 'debug' enabled.
2023-11-20 20:58:28.978 ERROR 10340 --- [           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; 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$Hikari.class]: Bean instantiation via factory method failed; nested exception is org.springframework.beans.BeanInstantiationException: Failed to instantiate [com.zaxxer.hikari.HikariDataSource]: Factory method 'dataSource' threw exception; nested exception is java.lang.IllegalStateException: Cannot load driver class: com.mysql.cj.jdbc.Driver 
    at org.springframework.beans.factory.support.ConstructorResolver.createArgumentArray(ConstructorResolver.java:801) ~[spring-beans-5.3.30.jar:5.3.30]
    at org.springframework.beans.factory.support.ConstructorResolver.instantiateUsingFactoryMethod(ConstructorResolver.java:536) ~[spring-beans-5.3.30.jar:5.3.30]
    at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.instantiateUsingFactoryMethod(AbstractAutowireCapableBeanFactory.java:1352) ~[spring-beans-5.3.30.jar:5.3.30]
    at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.createBeanInstance(AbstractAutowireCapableBeanFactory.java:1195) ~[spring-beans-5.3.30.jar:5.3.30]
    at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.doCreateBean(AbstractAutowireCapableBeanFactory.java:582) ~[spring-beans-5.3.30.jar:5.3.30]
    at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.createBean(AbstractAutowireCapableBeanFactory.java:542) ~[spring-beans-5.3.30.jar:5.3.30]
    at org.springframework.beans.factory.support.AbstractBeanFactory.lambda$doGetBean$0(AbstractBeanFactory.java:335) ~[spring-beans-5.3.30.jar:5.3.30]
    at org.springframework.beans.factory.support.DefaultSingletonBeanRegistry.getSingleton(DefaultSingletonBeanRegistry.java:234) ~[spring-beans-5.3.30.jar:5.3.30]
    at org.springframework.beans.factory.support.AbstractBeanFactory.doGetBean(AbstractBeanFactory.java:333) ~[spring-beans-5.3.30.jar:5.3.30]
    at org.springframework.beans.factory.support.AbstractBeanFactory.getBean(AbstractBeanFactory.java:208) ~[spring-beans-5.3.30.jar:5.3.30]
    at org.springframework.beans.factory.support.AbstractBeanFactory.doGetBean(AbstractBeanFactory.java:322) ~[spring-beans-5.3.30.jar:5.3.30]
    at org.springframework.beans.factory.support.AbstractBeanFactory.getBean(AbstractBeanFactory.java:208) ~[spring-beans-5.3.30.jar:5.3.30]
    at org.springframework.context.support.AbstractApplicationContext.getBean(AbstractApplicationContext.java:1160) ~[spring-context-5.3.30.jar:5.3.30]
    at org.springframework.context.support.AbstractApplicationContext.finishBeanFactoryInitialization(AbstractApplicationContext.java:911) ~[spring-context-5.3.30.jar:5.3.30]
    at org.springframework.context.support.AbstractApplicationContext.refresh(AbstractApplicationContext.java:583) ~[spring-context-5.3.30.jar:5.3.30]
    at org.springframework.boot.web.servlet.context.ServletWebServerApplicationContext.refresh(ServletWebServerApplicationContext.java:147) ~[spring-boot-2.7.17.jar:2.7.17]
    at org.springframework.boot.SpringApplication.refresh(SpringApplication.java:732) [spring-boot-2.7.17.jar:2.7.17]
    at org.springframework.boot.SpringApplication.refreshContext(SpringApplication.java:409) [spring-boot-2.7.17.jar:2.7.17]
    at org.springframework.boot.SpringApplication.run(SpringApplication.java:308) [spring-boot-2.7.17.jar:2.7.17]
    at org.springframework.boot.SpringApplication.run(SpringApplication.java:1300) [spring-boot-2.7.17.jar:2.7.17]
    at org.springframework.boot.SpringApplication.run(SpringApplication.java:1289) [spring-boot-2.7.17.jar:2.7.17]
    at com.egg.biblioteca.BibliotecaApplication.main(BibliotecaApplication.java:10) [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]: 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 java.lang.IllegalStateException: Cannot load driver class: com.mysql.cj.jdbc.Driver 
    at org.springframework.beans.factory.support.ConstructorResolver.instantiate(ConstructorResolver.java:653) ~[spring-beans-5.3.30.jar:5.3.30]
    at org.springframework.beans.factory.support.ConstructorResolver.instantiateUsingFactoryMethod(ConstructorResolver.java:633) ~[spring-beans-5.3.30.jar:5.3.30]
    at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.instantiateUsingFactoryMethod(AbstractAutowireCapableBeanFactory.java:1352) ~[spring-beans-5.3.30.jar:5.3.30]
    at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.createBeanInstance(AbstractAutowireCapableBeanFactory.java:1195) ~[spring-beans-5.3.30.jar:5.3.30]
    at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.doCreateBean(AbstractAutowireCapableBeanFactory.java:582) ~[spring-beans-5.3.30.jar:5.3.30]
    at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.createBean(AbstractAutowireCapableBeanFactory.java:542) ~[spring-beans-5.3.30.jar:5.3.30]
    at org.springframework.beans.factory.support.AbstractBeanFactory.lambda$doGetBean$0(AbstractBeanFactory.java:335) ~[spring-beans-5.3.30.jar:5.3.30]
    at org.springframework.beans.factory.support.DefaultSingletonBeanRegistry.getSingleton(DefaultSingletonBeanRegistry.java:234) ~[spring-beans-5.3.30.jar:5.3.30]
    at org.springframework.beans.factory.support.AbstractBeanFactory.doGetBean(AbstractBeanFactory.java:333) ~[spring-beans-5.3.30.jar:5.3.30]
    at org.springframework.beans.factory.support.AbstractBeanFactory.getBean(AbstractBeanFactory.java:208) ~[spring-beans-5.3.30.jar:5.3.30]
    at org.springframework.beans.factory.config.DependencyDescriptor.resolveCandidate(DependencyDescriptor.java:276) ~[spring-beans-5.3.30.jar:5.3.30]
    at org.springframework.beans.factory.support.DefaultListableBeanFactory.doResolveDependency(DefaultListableBeanFactory.java:1391) ~[spring-beans-5.3.30.jar:5.3.30]
    at org.springframework.beans.factory.support.DefaultListableBeanFactory.resolveDependency(DefaultListableBeanFactory.java:1311) ~[spring-beans-5.3.30.jar:5.3.30]
    at org.springframework.beans.factory.support.ConstructorResolver.resolveAutowiredArgument(ConstructorResolver.java:911) ~[spring-beans-5.3.30.jar:5.3.30]
    at org.springframework.beans.factory.support.ConstructorResolver.createArgumentArray(ConstructorResolver.java:788) ~[spring-beans-5.3.30.jar:5.3.30]
    ... 21 common frames omitted
Caused by: org.springframework.beans.BeanInstantiationException: Failed to instantiate [com.zaxxer.hikari.HikariDataSource]: Factory method 'dataSource' threw exception; nested exception is java.lang.IllegalStateException: Cannot load driver class: com.mysql.cj.jdbc.Driver 
    at org.springframework.beans.factory.support.SimpleInstantiationStrategy.instantiate(SimpleInstantiationStrategy.java:185) ~[spring-beans-5.3.30.jar:5.3.30]
    at org.springframework.beans.factory.support.ConstructorResolver.instantiate(ConstructorResolver.java:648) ~[spring-beans-5.3.30.jar:5.3.30]
    ... 35 common frames omitted
Caused by: java.lang.IllegalStateException: Cannot load driver class: com.mysql.cj.jdbc.Driver 
    at org.springframework.util.Assert.state(Assert.java:97) ~[spring-core-5.3.30.jar:5.3.30]
    at org.springframework.boot.autoconfigure.jdbc.DataSourceProperties.determineDriverClassName(DataSourceProperties.java:175) ~[spring-boot-autoconfigure-2.7.17.jar:2.7.17]
    at org.springframework.boot.autoconfigure.jdbc.DataSourceProperties.initializeDataSourceBuilder(DataSourceProperties.java:125) ~[spring-boot-autoconfigure-2.7.17.jar:2.7.17]
    at org.springframework.boot.autoconfigure.jdbc.DataSourceConfiguration.createDataSource(DataSourceConfiguration.java:48) ~[spring-boot-autoconfigure-2.7.17.jar:2.7.17]
    at org.springframework.boot.autoconfigure.jdbc.DataSourceConfiguration$Hikari.dataSource(DataSourceConfiguration.java:90) ~[spring-boot-autoconfigure-2.7.17.jar:2.7.17]
    at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method) ~[na:1.8.0_111]
    at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:62) ~[na:1.8.0_111]
    at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43) ~[na:1.8.0_111]
    at java.lang.reflect.Method.invoke(Method.java:498) ~[na:1.8.0_111]
    at org.springframework.beans.factory.support.SimpleInstantiationStrategy.instantiate(SimpleInstantiationStrategy.java:154) ~[spring-beans-5.3.30.jar:5.3.30]
36 common frames omitted

pom.xml内容 #

<?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>2.7.17</version>
        <relativePath/> <!-- lookup parent from repository -->
    </parent>
    <groupId>com.egg</groupId>
    <artifactId>biblioteca</artifactId>
    <version>0.0.1-SNAPSHOT</version>
    <name>biblioteca</name>
    <description>Proyecto de biblioteca Egg</description>
    <properties>
        <java.version>1.8</java.version>
    </properties>
    <dependencies>
        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-data-jpa</artifactId>
        </dependency>
        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-thymeleaf</artifactId>
        </dependency>
        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-web</artifactId>
        </dependency>

        <dependency>
            <groupId>com.mysql</groupId>
            <artifactId>mysql-connector-j</artifactId>
            <scope>runtime</scope>
        </dependency>
                
        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-test</artifactId>
            <scope>test</scope>
        </dependency>
    </dependencies>

    <build>
        <plugins>
            <plugin>
                <groupId>org.springframework.boot</groupId>
                <artifactId>spring-boot-maven-plugin</artifactId>
                <configuration>
                    <image>
                        <builder>paketobuildpacks/builder-jammy-base:latest</builder>
                    </image>
                </configuration>
            </plugin>
        </plugins>
    </build>

</project>

项目配置属性 #

spring.datasource.url: jdbc:mysql://localhost:3306/DATABASE?allowPublicKeyRetrieval=true&useSSL=false&use
Timezone=true&serverTimezone=GMT&characterEncoding=UTF-8
spring.datasource.username: root
spring.datasource.password: root
spring.datasource.driver-class-name: com.mysql.cj.jdbc.Driver 
spring.jpa.show-sql: true
spring.jpa.hibernate.ddl-auto: update
spring.jpa.properties.hibernate.dialect: org.hibernate.dialect.MySQL5InnoDBDialect
spring.thymeleaf.cache: false

环境信息 #

• Spring Boot 2.7.17
• Java 8
• MySQL驱动 8.0.33

排查解决方案 #

• 修复配置文件的格式错误：
  1. JDBC URL被换行拆分，合并为完整一行：jdbc:mysql://localhost:3306/DATABASE?allowPublicKeyRetrieval=true&useSSL=false&useTimezone=true&serverTimezone=GMT&characterEncoding=UTF-8
  2. 驱动类配置末尾有冗余空格，修改为：spring.datasource.driver-class-name: com.mysql.cj.jdbc.Driver
• 刷新Maven依赖：在Netbeans中右键项目 → Maven → Update Dependencies，确保mysql-connector-j依赖被正确下载到本地仓库。若依赖未下载，可删除本地仓库中对应驱动目录后重新执行更新。
• 清理并重新构建项目：在Netbeans中执行Clean and Build操作，清除旧编译文件，避免缓存导致的依赖加载异常。
• 确认项目Java版本：检查Netbeans项目属性 → 构建 → 编译，确保源代码和目标版本均设置为1.8，与环境Java版本一致。
• 验证驱动类存在性：打开本地Maven仓库中的mysql-connector-j-8.0.33.jar，确认com/mysql/cj/jdbc/Driver.class文件存在，若不存在则重新下载依赖。

内容的提问来源于stack exchange，提问作者Kelths