Failed to configure a DataSource: ‘url‘ attribute is not specified and no embedded datasource could

WARN  o.a.c.l.WebappClassLoaderBase - [log,173] - The web application [ROOT] appears to have started a thread named [Thread-5] but has failed to stop it. This is very likely to create a memory leak. Stack trace of thread:
 java.base@17.0.9/sun.net.dns.ResolverConfigurationImpl.notifyAddrChange0(Native Method)
 java.base@17.0.9/sun.net.dns.ResolverConfigurationImpl$AddressChangeListener.run(ResolverConfigurationImpl.java:176)
12:18:07.660 [restartedMain] ERROR o.s.b.d.LoggingFailureAnalysisReporter - [report,40] - 

***************************
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 suitable jdbc url


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 (the profiles dev are currently active).

Disconnected from the target VM, address: '127.0.0.1:61616', transport: 'socket'

Process finished with exit code 1

这个错误表明 Spring Boot 应用程序无法自动配置数据源，一般是因为没有在配置中指定url属性，并且也没有找到嵌入式数据库 

解决方案

1. 检查数据库配置文件

这个错误信息表明Spring Boot应用程序在尝试配置数据源时失败了，具体原因是因为没有指定url属性，并且没有找到可以自动配置的嵌入式数据源

1、可以去application-dev.yml文件里面核查配置项，如指定数据源URL：在application.properties或application.yml文件中的数据库连接URL的准确性。

2、添加嵌入式数据库依赖：如果你希望使用嵌入式数据库（如H2、HSQL或Derby），请确保在项目的依赖管理文件（如pom.xml或build.gradle）中包含了相应的依赖。

例如，对于H2数据库，添加：

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

3、检查配置文件路径：确保application.properties或application.yml文件位于正确的路径下，通常是src/main/resources目录。
4、检查配置文件名称：确保配置文件的名称正确无误，Spring Boot会自动加载这些文件来配置应用程序。