第一个Spring Boot程序启动报错了

创建完成第一个Spring Boot项目后，准备运行，尝一下胜利的果实。

启动日志如下

  .   ____          _            __ _ _
 /\\ / ___'_ __ _ _(_)_ __  __ _ \ \ \ \
( ( )\___ | '_ | '_| | '_ \/ _` | \ \ \ \
 \\/  ___)| |_)| | | | | || (_| |  ) ) ) )
  '  |____| .__|_| |_|_| |_\__, | / / / /
 =========|_|==============|___/=/_/_/_/
 :: Spring Boot ::        (v2.1.1.RELEASE)

-- ::41.812  INFO  --- [           main] com.example.demo01.Demo01Application     : Starting Demo01Application on - with PID  (D:\SpringBoot\project\demo01\target\classes started by Administrator in D:\SpringBoot\project\demo01)
-- ::41.821  INFO  --- [           main] com.example.demo01.Demo01Application     : No active profile set, falling back to default profiles: default
-- ::43.160  INFO  --- [           main] com.example.demo01.Demo01Application     : Started Demo01Application in 1.955 seconds (JVM running for 3.395)

Process finished with exit code 

没有报错，但是，这是一个web项目，为什么自己就结束了呢？

查阅资料（百度）

发现pom文件有问题，这里不啰嗦，直接上代码

<dependency>
			<groupId>org.springframework.boot</groupId>
			<artifactId>spring-boot-starter-tomcat</artifactId>
			<scope>provided</scope>
		</dependency>

pom文件中有这个依赖，这个是什么意思呢？

简单来说就是：我把外部的一个tomcat引入了。

这下你明白了吧，spring boot内部本来就有一个。你现在又引入了一个，这下出问题了。

解决方案：

把上述代码做掉（删除）。问题解决

重新启动项目：

日志如下

  .   ____          _            __ _ _
 /\\ / ___'_ __ _ _(_)_ __  __ _ \ \ \ \
( ( )\___ | '_ | '_| | '_ \/ _` | \ \ \ \
 \\/  ___)| |_)| | | | | || (_| |  ) ) ) )
  '  |____| .__|_| |_|_| |_\__, | / / / /
 =========|_|==============|___/=/_/_/_/
 :: Spring Boot ::        (v2.1.1.RELEASE)

-- ::18.385  INFO  --- [           main] com.example.demo01.Demo01Application     : Starting Demo01Application on - with PID  (D:\SpringBoot\project\demo01\target\classes started by Administrator in D:\SpringBoot\project\demo01)
-- ::18.391  INFO  --- [           main] com.example.demo01.Demo01Application     : No active profile set, falling back to default profiles: default
-- ::19.851  INFO  --- [           main] o.s.b.w.embedded.tomcat.TomcatWebServer  : Tomcat initialized with port(s):  (http)
-- ::19.875  INFO  --- [           main] o.apache.catalina.core.StandardService   : Starting service [Tomcat]
-- ::19.875  INFO  --- [           main] org.apache.catalina.core.StandardEngine  : Starting Servlet Engine: Apache Tomcat/9.0.
-- ::19.882  INFO  --- [           main] 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: [D:\Program Files\Java\jdk1..0_172\bin;C:\Windows\Sun\Java\bin;C:\Windows\system32;C:\Windows;D:\Python37;D:\Program Files (x86)\Sybase\PowerDesigner ;D:\oracle\product\10.2.\db_1\bin;D:\app\Administrator\product\11.2.\client_1;D:\maven\apache-maven-3.5.\bin;D:\Program Files\Java\jdk1..0_80\bin;C:\Windows\system32;C:\Windows;C:\Windows\System32\Wbem;C:\Windows\System32\WindowsPowerShell\v1.\;D:\Program Files\TortoiseSVN\bin;C:\Program Files (x86)\MySQL\MySQL Server 5.5\bin;D:\Program Files\EmEditor;D:\Python37\Scripts;D:\Python37\Lib\site-packages\Django-2.1.-py3..egg\django;D:\Program Files\Git\cmd;D:\Python37\Scripts\;D:\Python37\;.]
-- ::20.011  INFO  --- [           main] o.a.c.c.C.[Tomcat].[localhost].[/]       : Initializing Spring embedded WebApplicationContext
-- ::20.011  INFO  --- [           main] o.s.web.context.ContextLoader            : Root WebApplicationContext: initialization completed in  ms
-- ::20.236  INFO  --- [           main] o.s.s.concurrent.ThreadPoolTaskExecutor  : Initializing ExecutorService 'applicationTaskExecutor'
-- ::20.463  INFO  --- [           main] o.s.b.w.embedded.tomcat.TomcatWebServer  : Tomcat started on port(s):  (http) with context path ''
-- ::20.469  INFO  --- [           main] com.example.demo01.Demo01Application     : Started Demo01Application in 2.713 seconds (JVM running for 3.954)

未完待续。。。。。。。。。

下面继续....

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