######为什么运行了 localhost 8080 没有变化呀
idea的代码：
```java
spring:
datasource:
username: root
password: asd123
driver-class-name: com.mysql.cj.jdbc.Driver
url: jdbc:mysql://127.0.0.1:3306/stuinfosystem?useUnicode=true&characterEncoding=utf8&useSSL=false&serverTimezone=Hongkong&useAffectedRows=true
type: com.alibaba.druid.pool.DruidDataSource
# 数据源其他配置
initialSize: 5
minIdle: 5
maxActive: 20
maxWait: 60000
thymeleaf:
cache: false
encoding: UTF-8
http:
encoding:
charset: UTF-8
mybatis:
configuration:
map-underscore-to-camel-case: true
server:
port: 8080
tomcat:
uri-encoding: utf-8
pagehelper:
helperDialect: mysql
reasonable: true
supportMethodsArguments: true
运行结果：
```java
org.apache.catalina.LifecycleException: Failed to start component [Connector[HTTP/1.1-8080]]
at org.apache.catalina.util.LifecycleBase.start(LifecycleBase.java:167) ~[tomcat-embed-core-8.5.27.jar:8.5.27]
at org.apache.catalina.core.StandardService.addConnector(StandardService.java:225) ~[tomcat-embed-core-8.5.27.jar:8.5.27]
at org.springframework.boot.context.embedded.tomcat.TomcatEmbeddedServletContainer.addPreviouslyRemovedConnectors(TomcatEmbeddedServletContainer.java:250) [spring-boot-1.5.10.RELEASE.jar:1.5.10.RELEASE]
at org.springframework.boot.context.embedded.tomcat.TomcatEmbeddedServletContainer.start(TomcatEmbeddedServletContainer.java:193) [spring-boot-1.5.10.RELEASE.jar:1.5.10.RELEASE]
at org.springframework.boot.context.embedded.EmbeddedWebApplicationContext.startEmbeddedServletContainer(EmbeddedWebApplicationContext.java:297) [spring-boot-1.5.10.RELEASE.jar:1.5.10.RELEASE]
at org.springframework.boot.context.embedded.EmbeddedWebApplicationContext.finishRefresh(EmbeddedWebApplicationContext.java:145) [spring-boot-1.5.10.RELEASE.jar:1.5.10.RELEASE]
at org.springframework.context.support.AbstractApplicationContext.refresh(AbstractApplicationContext.java:546) [spring-context-4.3.14.RELEASE.jar:4.3.14.RELEASE]
at org.springframework.boot.context.embedded.EmbeddedWebApplicationContext.refresh(EmbeddedWebApplicationContext.java:122) [spring-boot-1.5.10.RELEASE.jar:1.5.10.RELEASE]
at org.springframework.boot.SpringApplication.refresh(SpringApplication.java:693) [spring-boot-1.5.10.RELEASE.jar:1.5.10.RELEASE]
at org.springframework.boot.SpringApplication.refreshContext(SpringApplication.java:360) [spring-boot-1.5.10.RELEASE.jar:1.5.10.RELEASE]
at org.springframework.boot.SpringApplication.run(SpringApplication.java:303) [spring-boot-1.5.10.RELEASE.jar:1.5.10.RELEASE]
at org.springframework.boot.SpringApplication.run(SpringApplication.java:1118) [spring-boot-1.5.10.RELEASE.jar:1.5.10.RELEASE]
at org.springframework.boot.SpringApplication.run(SpringApplication.java:1107) [spring-boot-1.5.10.RELEASE.jar:1.5.10.RELEASE]
at com.lc.demo.DemoApplication.main(DemoApplication.java:12) [classes/:na]
Caused by: org.apache.catalina.LifecycleException: Protocol handler start failed
at org.apache.catalina.connector.Connector.startInternal(Connector.java:1021) ~[tomcat-embed-core-8.5.27.jar:8.5.27]
at org.apache.catalina.util.LifecycleBase.start(LifecycleBase.java:150) ~[tomcat-embed-core-8.5.27.jar:8.5.27]
... 13 common frames omitted
Caused by: java.net.BindException: Address already in use: bind
at sun.nio.ch.Net.bind0(Native Method) ~[na:1.8.0_181]
at sun.nio.ch.Net.bind(Net.java:433) ~[na:1.8.0_181]
at sun.nio.ch.Net.bind(Net.java:425) ~[na:1.8.0_181]
at sun.nio.ch.ServerSocketChannelImpl.bind(ServerSocketChannelImpl.java:223) ~[na:1.8.0_181]
at sun.nio.ch.ServerSocketAdaptor.bind(ServerSocketAdaptor.java:74) ~[na:1.8.0_181]
at org.apache.tomcat.util.net.NioEndpoint.bind(NioEndpoint.java:210) ~[tomcat-embed-core-8.5.27.jar:8.5.27]
at org.apache.tomcat.util.net.AbstractEndpoint.start(AbstractEndpoint.java:1150) ~[tomcat-embed-core-8.5.27.jar:8.5.27]
at org.apache.coyote.AbstractProtocol.start(AbstractProtocol.java:591) ~[tomcat-embed-core-8.5.27.jar:8.5.27]
at org.apache.catalina.connector.Connector.startInternal(Connector.java:1018) ~[tomcat-embed-core-8.5.27.jar:8.5.27]
... 14 common frames omitted
2022-12-09 17:18:54.179 INFO 10616 --- [ main] o.apache.catalina.core.StandardService : Stopping service [Tomcat]
2022-12-09 17:18:54.189 INFO 10616 --- [ main] utoConfigurationReportLoggingInitializer :
Error starting ApplicationContext. To display the auto-configuration report re-run your application with 'debug' enabled.
2022-12-09 17:18:54.192 ERROR 10616 --- [ main] o.s.b.d.LoggingFailureAnalysisReporter :
***************************
APPLICATION FAILED TO START
***************************
Description:
The Tomcat connector configured to listen on port 8080 failed to start. The port may already be in use or the connector may be misconfigured.
Action:
Verify the connector's configuration, identify and stop any process that's listening on port 8080, or configure this application to listen on another port.
2022-12-09 17:18:54.193 INFO 10616 --- [ main] ationConfigEmbeddedWebApplicationContext : Closing org.springframework.boot.context.embedded.AnnotationConfigEmbeddedWebApplicationContext@41fbdac4: startup date [Fri Dec 09 17:18:51 GMT+08:00 2022]; root of context hierarchy
2022-12-09 17:18:54.194 INFO 10616 --- [ main] o.s.j.e.a.AnnotationMBeanExporter : Unregistering JMX-exposed beans on shutdown
2022-12-09 17:18:54.194 INFO 10616 --- [ main] o.s.j.e.a.AnnotationMBeanExporter : Unregistering JMX-exposed beans
Process finished with exit code 1
8080端口 被占用了，换个端口，或者找到占用这个端口的进程，kill掉
端口占用，，应该是你上一次运行没有停止，或者您换一个端口