Spring Boot启动失败：webMvcMetricsFilter Bean创建异常及数据源问题

问题现象 #

启动项目时抛出org.springframework.beans.factory.UnsatisfiedDependencyException，提示创建名为webMvcMetricsFilter的Bean失败，最终根源为无法确定合适的数据源驱动类。

控制台错误日志 #

2023-02-24 09:37:19.082 ERROR 41612 --- [  restartedMain] o.s.b.web.embedded.tomcat.TomcatStarter  : Error starting Tomcat context. Exception: org.springframework.beans.factory.UnsatisfiedDependencyException. Message: Error creating bean with name 'webMvcMetricsFilter' defined in class path resource [org/springframework/boot/actuate/autoconfigure/metrics/web/servlet/WebMvcMetricsAutoConfiguration.class]: Unsatisfied dependency expressed through method 'webMvcMetricsFilter' parameter 0; nested exception is org.springframework.beans.factory.BeanCreationException: Error creating bean with name 'simpleMeterRegistry' defined in class path resource [org/springframework/boot/actuate/autoconfigure/metrics/export/simple/SimpleMetricsExportAutoConfiguration.class]: Initialization of bean failed; nested exception is org.springframework.beans.factory.UnsatisfiedDependencyException: Error creating bean with name 'dataSourcePoolMetadataMeterBinder' defined in class path resource [org/springframework/boot/actuate/autoconfigure/metrics/jdbc/DataSourcePoolMetricsAutoConfiguration$DataSourcePoolMetadataMetricsConfiguration.class]: Unsatisfied dependency expressed through method 'dataSourcePoolMetadataMeterBinder' parameter 0; nested exception is org.springframework.beans.factory.BeanCreationException: Error creating bean with name 'dataSource' defined in class path resource [org/springframework/boot/autoconfigure/jdbc/DataSourceConfiguration$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.autoconfigure.jdbc.DataSourceProperties$DataSourceBeanCreationException: Failed to determine a suitable driver class
2023-02-24 09:37:19.349  INFO 41612 --- [  restartedMain] o.apache.catalina.core.StandardService   : Stopping service [Tomcat]
2023-02-24 09:37:19.705  WARN 41612 --- [  restartedMain] ConfigServletWebServerApplicationContext : Exception encountered during context initialization - cancelling refresh attempt: org.springframework.context.ApplicationContextException: Unable to start web server; nested exception is org.springframework.boot.web.server.WebServerException: Unable to start embedded Tomcat
2023-02-24 09:37:19.837  INFO 41612 --- [  restartedMain] ConditionEvaluationReportLoggingListener : 

Error starting ApplicationContext. To display the conditions report re-run your application with 'debug' enabled.
2023-02-24 09:37:19.970 ERROR 41612 --- [  restartedMain] o.s.b.d.LoggingFailureAnalysisReporter   : 

***************************
APPLICATION FAILED TO START
***************************

核心错误提示 #

Failed to configure a DataSource: 'url' attribute is not specified and no embedded datasource could be configured.

原因：Failed to determine a suitable driver class

系统建议：
If you want an embedded database (H2, HSQL or Derby), please put it on the classpath.
If you have database settings to be loaded from a particular profile you may need to activate it (no profiles are currently active).

项目配置信息 #

pom.xml #

<?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>2.7.8</version>
        <relativePath /> <!-- lookup parent from repository -->
    </parent>
    <groupId>com.car</groupId>
    <artifactId>car</artifactId>
    <version>0.0.1-SNAPSHOT</version>
    <name>car-demo</name>
    <description>Demo project for Spring Boot</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>org.springframework.boot</groupId>
            <artifactId>spring-boot-devtools</artifactId>
            <scope>runtime</scope>
            <optional>true</optional>
        </dependency>
        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-test</artifactId>
            <scope>test</scope>
        </dependency>
        <dependency>
            <groupId>javax.persistence</groupId>
            <artifactId>javax.persistence-api</artifactId>
        </dependency>
        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-data-jpa</artifactId>
        </dependency>
        <dependency>
            <groupId>com.mysql</groupId>
            <artifactId>mysql-connector-j</artifactId>
        </dependency>
        <!-- https://mvnrepository.com/artifact/org.springframework.boot/spring-boot-starter-actuator -->
        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-actuator</artifactId>
            <version>2.7.8</version>
        </dependency>
    </dependencies>
    <build>
        <plugins>
            <plugin>
                <groupId>org.springframework.boot</groupId>
                <artifactId>spring-boot-maven-plugin</artifactId>
            </plugin>
        </plugins>
    </build>
</project>

application.properties #

spring.datasource.driver-class-name=com.mysql.jdbc.Driver
spring.datasource.url=jdbc:mysql://127.0.0.1:3306/cardb
spring.datasource.username=root
spring.datasource.password=root
spring.datasource.tomcat.max-wait=20000
spring.datasource.tomcat.max-active=50
spring.datasource.tomcat.max-idle=20
spring.datasource.tomcat.min-idle=15
spring.jpa.properties.hibernate.dialect = org.hibernate.dialect.MySQLDialect
spring.jpa.properties.hibernate.id.new_generator_mappings = false
spring.jpa.properties.hibernate.format_sql = true
logging.level.org.hibernate.SQL=DEBUG
logging.level.org.hibernate.type.descriptor.sql.BasicBinder=TRACE

主类代码 #

package com.car;

import org.springframework.boot.SpringApplication;
import org.springframework.boot.autoconfigure.SpringBootApplication;

@SpringBootApplication
public class CarDemoApplication {

    public static void main(String[] args) {
        SpringApplication.run(CarDemoApplication.class, args);
        System.out.println("hello from car");
    }
}

已尝试无效操作 #

• 移除部分依赖
• 参考相关解决方案（未解决）

解决办法 #

1. 修正MySQL驱动类配置 #

当前使用的mysql-connector-j是8.x版本，旧版驱动类com.mysql.jdbc.Driver已废弃，需替换为：

spring.datasource.driver-class-name=com.mysql.cj.jdbc.Driver

2. 验证MySQL服务与数据库状态 #

• 确认本地MySQL服务已启动，端口3306正常监听
• 手动创建cardb数据库（若不存在）

3. 修复连接池配置前缀 #

Spring Boot 2.7.x默认使用HikariCP作为数据源，原配置中spring.datasource.tomcat.*前缀无效，需改为HikariCP的配置前缀：

spring.datasource.hikari.max-wait=20000
spring.datasource.hikari.maximum-pool-size=50
spring.datasource.hikari.minimum-idle=15

4. 刷新Maven依赖 #

执行以下命令确保mysql-connector-j依赖正确下载：

mvn clean install -U

内容的提问来源于stack exchange，提问作者Dark Night