Spring Boot应用启动失败：DataSource配置问题求助

我通过Spring Initializer创建了一个Spring Boot应用，在IntelliJ IDEA中运行时启动失败。

启动类代码 #

package com.demo.grocery;

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

@SpringBootApplication
public class GroceryApplication {

    public static void main(String[] args) {
        SpringApplication.run(GroceryApplication.class, args);
    }

}

报错日志 #

.   ____          _            __ _ _
 /\/ ___'_ __ _ _(_)_ __  __ _ \ \ \ \
( ( )\___ | '_ | '_| | '_ \/ _` | \ \ \ \
 \\/  ___)| |_)| | | | | || (_| |  ) ) ) )
  '  |____| .__|_| |_|_| |_\__, | / / / /
 =========|_|==============|___/=/_/_/_/
 :: Spring Boot ::                (v2.7.2)

2022-07-29 22:12:46.331  INFO 14136 --- [           main] com.demo.grocery.GroceryApplication      : Starting GroceryApplication using Java 11.0.13 on DESKTOP-MQ2O3FR with PID 14136 (C:\Users\keerthi\Downloads\grocery\target\classes started by keerthi in C:\Users\keerthi\Downloads\grocery)
2022-07-29 22:12:46.336  INFO 14136 --- [           main] com.demo.grocery.GroceryApplication      : No active profile set, falling back to 1 default profile: "default"
2022-07-29 22:12:47.288  INFO 14136 --- [           main] .s.d.r.c.RepositoryConfigurationDelegate : Bootstrapping Spring Data JPA repositories in DEFAULT mode.
2022-07-29 22:12:47.306  INFO 14136 --- [           main] .s.d.r.c.RepositoryConfigurationDelegate : Finished Spring Data repository scanning in 7 ms. Found 0 JPA repository interfaces.
2022-07-29 22:12:48.437  INFO 14136 --- [           main] o.s.b.w.embedded.tomcat.TomcatWebServer  : Tomcat initialized with port(s): 8080 (http)
2022-07-29 22:12:48.463  INFO 14136 --- [           main] o.apache.catalina.core.StandardService   : Starting service [Tomcat]
2022-07-29 22:12:48.463  INFO 14136 --- [           main] org.apache.catalina.core.StandardEngine  : Starting Servlet engine: [Apache Tomcat/9.0.65]
2022-07-29 22:12:48.721  INFO 14136 --- [           main] o.a.c.c.C.[Tomcat].[localhost].[/]       : Initializing Spring embedded WebApplicationContext
2022-07-29 22:12:48.721  INFO 14136 --- [           main] w.s.c.ServletWebServerApplicationContext : Root WebApplicationContext: initialization completed in 2267 ms
2022-07-29 22:12:48.832  WARN 14136 --- [           main] ConfigServletWebServerApplicationContext : Exception encountered during context initialization - cancelling refresh attempt: 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$Hikari.class]: Bean instantiation via factory method failed; nested exception is org.springframework.beans.BeanInstantiationException: Failed to instantiate [com.zaxxer.hikari.HikariDataSource]: Factory method 'dataSource' threw exception; nested exception is org.springframework.boot.autoconfigure.jdbc.DataSourceProperties$DataSourceBeanCreationException: Failed to determine a suitable driver class
2022-07-29 22:12:48.839  INFO 14136 --- [           main] o.apache.catalina.core.StandardService   : Stopping service [Tomcat]
2022-07-29 22:12:48.868  INFO 14136 --- [           main] ConditionEvaluationReportLoggingListener : 

Error starting ApplicationContext. To display the conditions report re-run your application with 'debug' enabled.
2022-07-29 22:12:48.897 ERROR 14136 --- [           main] o.s.b.d.LoggingFailureAnalysisReporter   : 

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

Description:

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

Reason: Failed to determine a suitable driver class


Action:

Consider the following:
    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).


Process finished with exit code 1

解决方案 #

情况1：需要数据库连接 #

如果你的应用确实需要访问数据库，按以下方式配置：

• 使用嵌入式数据库（如H2）
  在Maven的pom.xml中添加H2依赖：

  <dependency>
      <groupId>com.h2database</groupId>
      <artifactId>h2</artifactId>
      <scope>runtime</scope>
  </dependency>
  

  然后在application.properties中配置数据源信息：

  spring.datasource.url=jdbc:h2:mem:testdb
  spring.datasource.driverClassName=org.h2.Driver
  spring.datasource.username=sa
  spring.datasource.password=
  spring.jpa.database-platform=org.hibernate.dialect.H2Dialect
  

• 使用外部数据库（如MySQL）
  在Maven的pom.xml中添加MySQL驱动依赖：

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

  然后在application.properties中配置对应数据库信息：

  spring.datasource.url=jdbc:mysql://localhost:3306/your_db_name?useSSL=false&serverTimezone=UTC
  spring.datasource.driverClassName=com.mysql.cj.jdbc.Driver
  spring.datasource.username=your_db_username
  spring.datasource.password=your_db_password
  spring.jpa.hibernate.ddl-auto=update
  

情况2：不需要数据库连接 #

如果你的应用只是简单的Web服务，不需要数据库，可以在启动类中排除数据源自动配置：

package com.demo.grocery;

import org.springframework.boot.SpringApplication;
import org.springframework.boot.autoconfigure.SpringBootApplication;
import org.springframework.boot.autoconfigure.jdbc.DataSourceAutoConfiguration;
import org.springframework.boot.autoconfigure.jdbc.DataSourceTransactionManagerAutoConfiguration;
import org.springframework.boot.autoconfigure.orm.jpa.HibernateJpaAutoConfiguration;

@SpringBootApplication(exclude = {
        DataSourceAutoConfiguration.class,
        DataSourceTransactionManagerAutoConfiguration.class,
        HibernateJpaAutoConfiguration.class
})
public class GroceryApplication {

    public static void main(String[] args) {
        SpringApplication.run(GroceryApplication.class, args);
    }

}

内容的提问来源于stack exchange，提问作者Keerthi Senthil