Failed to configure a DataSource: ‘url’ attribute is not specified and no embedded (How to Fix)

when setting up springboot, boot fails with the error 

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

the solution: add a exclude = DataSourceAutoConfiguration. Class

before:

package App;

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

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

after:

package App;

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

@SpringBootApplication(exclude = DataSourceAutoConfiguration.class)
public class App {
	public static void main(String[] args) {
		SpringApplication.run(App.class, args);
	}
}

works normally, solve 


  .   ____          _            __ _ _
 /\\/___'_ __ _ _(_)_ __  __ _ \ \ \ \
( ( )\___ | '_ | '_| | '_ \/ _` | \ \ \ \
 \\/  ___)| |_)| | | | | || (_| |  ) ) ) )
  '  |____| .__|_| |_|_| |_\__, |////
 =========|_|==============|___/=/_/_/_/
 :: Spring Boot ::        (v2.0.5.RELEASE)

2018-10-13 10:38:15.265  INFO 7288 --- [           main] App.App                                  : Starting App on Y9SVAFMN942HYRY with PID 7288 (D:\boot_1\target\classes started by Administrator in D:\boot_1)
2018-10-13 10:38:15.271  INFO 7288 --- [           main] App.App                                  : No active profile set, falling back to default profiles: default
2018-10-13 10:38:15.453  INFO 7288 --- [           main] ConfigServletWebServerApplicationContext : Refreshing org.springframework.boot.web.servlet.context.AnnotationConfigServletWebServerApplicationContext@50a6f6: startup date [Sat Oct 13 10:38:15 CST 2018]; root of context hierarchy
2018-10-13 10:38:18.881  INFO 7288 --- [           main] o.s.b.w.embedded.tomcat.TomcatWebServer  : Tomcat initialized with port(s): 8080 (http)
2018-10-13 10:38:18.942  INFO 7288 --- [           main] o.apache.catalina.core.StandardService   : Starting service [Tomcat]
2018-10-13 10:38:18.942  INFO 7288 --- [           main] org.apache.catalina.core.StandardEngine  : Starting Servlet Engine: Apache Tomcat/8.5.34
2018-10-13 10:38:18.967  INFO 7288 --- [ost-startStop-1] o.a.catalina.core.AprLifecycleListener   : The APR based Apache Tomcat Native library which allows optimal performance in production environments was not found on the java.library.path: [C:\Program Files\Java\jre1.8.0_161\bin;C:\Windows\Sun\Java\bin;C:\Windows\system32;C:\Windows;C:/Program Files/Java/jre1.8.0_161/bin/client;C:/Program Files/Java/jre1.8.0_161/bin;C:/Program Files/Java/jre1.8.0_161/lib/i386;C:\ProgramData\Oracle\Java\javapath;C:\Windows\system32;C:\Windows;C:\Windows\System32\Wbem;C:\Windows\System32\WindowsPowerShell\v1.0\;E:\namd-tutorial\NAMD_2.8\NAMD_2.8_Win32-multicore;D:\Program Files\Anaconda3;D:\Program Files\Anaconda3\Scripts;D:\Program Files\Anaconda3\Library\bin;;D:\eclipse-jee-oxygen-3-win32\eclipse;;.]
2018-10-13 10:38:19.506  INFO 7288 --- [ost-startStop-1] org.apache.jasper.servlet.TldScanner     : At least one JAR was scanned for TLDs yet contained no TLDs. Enable debug logging for this logger for a complete list of JARs that were scanned but no TLDs were found in them. Skipping unneeded JARs during scanning can improve startup time and JSP compilation time.
2018-10-13 10:38:19.515  INFO 7288 --- [ost-startStop-1] o.a.c.c.C.[Tomcat].[localhost].[/]       : Initializing Spring embedded WebApplicationContext
2018-10-13 10:38:19.515  INFO 7288 --- [ost-startStop-1] o.s.web.context.ContextLoader            : Root WebApplicationContext: initialization completed in 4066 ms
2018-10-13 10:38:20.059  INFO 7288 --- [ost-startStop-1] o.s.b.w.servlet.ServletRegistrationBean  : Servlet dispatcherServlet mapped to [/]
2018-10-13 10:38:20.068  INFO 7288 --- [ost-startStop-1] o.s.b.w.servlet.FilterRegistrationBean   : Mapping filter: 'characterEncodingFilter' to: [/*]
2018-10-13 10:38:20.069  INFO 7288 --- [ost-startStop-1] o.s.b.w.servlet.FilterRegistrationBean   : Mapping filter: 'hiddenHttpMethodFilter' to: [/*]
2018-10-13 10:38:20.069  INFO 7288 --- [ost-startStop-1] o.s.b.w.servlet.FilterRegistrationBean   : Mapping filter: 'httpPutFormContentFilter' to: [/*]
2018-10-13 10:38:20.070  INFO 7288 --- [ost-startStop-1] o.s.b.w.servlet.FilterRegistrationBean   : Mapping filter: 'requestContextFilter' to: [/*]
2018-10-13 10:38:20.367  INFO 7288 --- [           main] o.s.w.s.handler.SimpleUrlHandlerMapping  : Mapped URL path [/**/favicon.ico] onto handler of type [class org.springframework.web.servlet.resource.ResourceHttpRequestHandler]
2018-10-13 10:38:20.993  INFO 7288 --- [           main] s.w.s.m.m.a.RequestMappingHandlerAdapter : Looking for @ControllerAdvice: org.springframework.boot.web.servlet.context.AnnotationConfigServletWebServerApplicationContext@50a6f6: startup date [Sat Oct 13 10:38:15 CST 2018]; root of context hierarchy
2018-10-13 10:38:21.159  INFO 7288 --- [           main] s.w.s.m.m.a.RequestMappingHandlerMapping : Mapped "{[/error]}" onto public org.springframework.http.ResponseEntity<java.util.Map<java.lang.String, java.lang.Object>> org.springframework.boot.autoconfigure.web.servlet.error.BasicErrorController.error(javax.servlet.http.HttpServletRequest)
2018-10-13 10:38:21.162  INFO 7288 --- [           main] s.w.s.m.m.a.RequestMappingHandlerMapping : Mapped "{[/error],produces=[text/html]}" onto public org.springframework.web.servlet.ModelAndView org.springframework.boot.autoconfigure.web.servlet.error.BasicErrorController.errorHtml(javax.servlet.http.HttpServletRequest,javax.servlet.http.HttpServletResponse)
2018-10-13 10:38:21.216  INFO 7288 --- [           main] o.s.w.s.handler.SimpleUrlHandlerMapping  : Mapped URL path [/webjars/**] onto handler of type [class org.springframework.web.servlet.resource.ResourceHttpRequestHandler]
2018-10-13 10:38:21.216  INFO 7288 --- [           main] o.s.w.s.handler.SimpleUrlHandlerMapping  : Mapped URL path [/**] onto handler of type [class org.springframework.web.servlet.resource.ResourceHttpRequestHandler]
2018-10-13 10:38:21.662  INFO 7288 --- [           main] o.s.j.e.a.AnnotationMBeanExporter        : Registering beans for JMX exposure on startup
2018-10-13 10:38:21.920  INFO 7288 --- [           main] o.s.b.w.embedded.tomcat.TomcatWebServer  : Tomcat started on port(s): 8080 (http) with context path ''
2018-10-13 10:38:21.926  INFO 7288 --- [           main] App.App                                  : Started App in 7.938 seconds (JVM running for 8.682)


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