關於idea中SpringBoot啟動失敗的坑

很多時候你新建了Maven 或者SpringBoot 工程，激動的點了主啟動類，你就發現了下面的錯誤

 

 

 Error starting Tomcat context. Exception: org.springframework.beans.factory.BeanCreationException. Message: 
Error creating bean with name 'servletEndpointRegistrar' defined in class path resource 
[org/springframework/boot/actuate/autoconfigure/endpoint/web/ServletEndpointManagementContextConfiguration$
WebMvcServletEndpointManagementContextConfiguration.class]: 
Bean instantiation via factory method failed; nested exception is org.springframework.beans.BeanInstantiationException: 
Failed to instantiate [org.springframework.boot.actuate.endpoint.web.ServletEndpointRegistrar]: 
Factory method 'servletEndpointRegistrar' threw exception; 
nested exception is org.springframework.beans.factory.UnsatisfiedDependencyException: 
Error creating bean with name 'healthEndpoint' defined in class path resource 
[org/springframework/boot/actuate/autoconfigure/health/HealthEndpointConfiguration.class]: 
Unsatisfied dependency expressed through method 'healthEndpoint' parameter 0; 
nested exception is org.springframework.beans.factory.BeanCreationException: 
Error creating bean with name 'healthContributorRegistry' defined in class path resource 
[org/springframework/boot/actuate/autoconfigure/health/HealthEndpointConfiguration.class]: 
Bean instantiation via factory method failed; nested exception is org.springframework.beans.BeanInstantiationException: 
Failed to instantiate [org.springframework.boot.actuate.health.HealthContributorRegistry]: 
Factory method 'healthContributorRegistry' threw exception; 
nested exception is org.springframework.beans.factory.UnsatisfiedDependencyException: 
Error creating bean with name 'org.springframework.boot.actuate.autoconfigure.jdbc.DataSourceHealthContributorAutoConfiguration': 
Unsatisfied dependency expressed through constructor 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
[  restartedMain] o.apache.catalina.core.StandardService   : Stopping service [Tomcat]
 --- [  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
 --- [  restartedMain] ConditionEvaluationReportLoggingListener : 

Error starting ApplicationContext. To display the conditions report re-run your application with 'debug' enabled.
2020-09-03 13:12:04.338 ERROR 24572 --- [  restartedMain] 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).

　　這里說的是啥意思呢，你沒有數據庫相關的鏈接，數據庫相關的鏈接在哪里配置呢，就是在你的Resource文件目錄下的properties 或者yml文件中

但是這里你可能會說，我**不用數據庫，我干啥配這個b玩意，我想說這句話的時候，你已經點了很多遍的主啟動都報這個錯誤，

今天你算來對了，我敢肯定80%的人都遇到過這個問題。但是不知道為啥，今天我給你分析一下昂：

①：在IDEA 中用SpringInitial  點點點生成的SpringBoot/cloud項目
②：跟視頻操作，一頓操作后發現不能啟動，
③：DonwLoad下的代碼   復制進去的POM依賴

還有很多昂，不墨跡了說重點吧。
解決方法：

首先着重看自己的POM依賴（是自己的POM，不是父工程，也不是其他工程，是自己的）中有無以下依賴

 

 

<dependency>
            <groupId>mysql</groupId>
            <artifactId>mysql-connector-java</artifactId>
            <version>${mysql.version}</version>
</dependency>

　　

<dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-jdbc</artifactId>
</dependency>

　　經過鄙人的測試，就是第一個依賴搗的鬼，這就是為啥你加了這個依賴你不配置相關的mysql鏈接，Spring就給你報錯的原因。

 

 

最后提醒：按需注入POM才是正道，老鐵們，我做的對么？