SpringBoot 创建空项目失败: 'dataSource' url error划重点：springboot 的@S

rror starting ApplicationContext. To display the conditions report re-run your application with 'debug' enabled.
2023-11-29 20:04:59.088 ERROR 30892 --- [           main] o.s.boot.SpringApplication               : Application run failed
org.springframework.beans.factory.BeanCreationException: Error creating bean with name 'entityManagerFactory' defined in class path resource [org/springframework/boot/autoconfigure/orm/jpa/HibernateJpaConfiguration.class]: Bean instantiation via factory method failed; nested exception is org.springframework.beans.BeanInstantiationException: Failed to instantiate [org.springframework.orm.jpa.LocalContainerEntityManagerFactoryBean]: Factory method 'entityManagerFactory' threw exception; nested exception is org.springframework.beans.factory.BeanCreationException: Error creating bean with name 'scopedTarget.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
划重点：springboot 的@SpringBootApplication注解会自动去初始化数据库连接池，不配置的话会启动失败，如下提示：
Exception encountered during context initialization - cancelling refresh attempt: org.springframework.beans.factory.BeanCreationException: Error creating bean with name 'dataSource' defined in class path resource [org/springframework/boot/autoconfigure/jdbc/DataSourceConfiguration $Dbcp2.class]: Bean instantiation via factory method failed; nested exception is org.springframework.beans.BeanInstantiationException: Failed to instantiate [org.apache.commons.dbcp2.BasicDataSource]: Factory method 'dataSource' threw exception; nested exception is org.springframework.boot.autoconfigure.jdbc.DataSourceProperties$ 
下面两种解决方案根据情况选择
如果需要当前服务需要数据库，就添加数据库配置；
如果当前服务不需要数据库，就用方法2 排除数据库连接池初始化。
1. 添加数据库配置
/gateway/src/main/resources/application.yml
添加如下代码：
spring:
    datasource:
        driver-class-name: com.mysql.cj.jdbc.Driver
        url: jdbc:mysql://192.168.88.151:3306/springcloud-alibaba-gateway?serverTimezone=UTC&useUnicode=true&characterEncoding=utf8&useSSL=false
        username: root
        password: root
2. 排除 <Springboot 初始化数据库连接池> 这个步骤
在启动类里，如下添加如下代码：
//启动类：/gateway/src/main/java/org/example/GatewayApplication.java

@SpringBootApplication(exclude = {DataSourceAutoConfiguration.class})
package org.example;
import org.springframework.boot.SpringApplication;
import org.springframework.boot.autoconfigure.SpringBootApplication;
import org.springframework.boot.autoconfigure.jdbc.DataSourceAutoConfiguration;
import org.springframework.cloud.client.discovery.EnableDiscoveryClient;
@EnableDiscoveryClient
@SpringBootApplication(exclude = {DataSourceAutoConfiguration.class})
public class GatewayApplication {
    public static void main(String[] args) {
        SpringApplication.run(GatewayApplication.class, args);
        大数据工程/后端工程师/前端划水运动员