【问题描述】：启动SpringBoot项目时，报如下堆栈错误
32.014 ERROR c.z.hikari.pool.HikariPool :594 restartedMain HikariPool-1 - Exception during pool initialization. com.mysql.cj.jdbc.exceptions.CommunicationsException: Communications link failure The last packet sent successfully to the server was 0 milliseconds ago. The driver has not received any packets from the server. at com.mysql.cj.jdbc.exceptions.SQLError.createCommunicationsException(SQLError.java:174) at com.mysql.cj.jdbc.exceptions.SQLExceptionsMapping.translateException(SQLExceptionsMapping.java:64) at com.mysql.cj.jdbc.ConnectionImpl.createNewIO(ConnectionImpl.java:833) at com.mysql.cj.jdbc.ConnectionImpl.(ConnectionImpl.java:453) at com.mysql.cj.jdbc.ConnectionImpl.getInstance(ConnectionImpl.java:246) at com.mysql.cj.jdbc.NonRegisteringDriver.connect(NonRegisteringDriver.java:198) at com.zaxxer.hikari.util.DriverDataSource.getConnection(DriverDataSource.java:138) at com.zaxxer.hikari.pool.Poolbase.newConnection(Poolbase.java:364) at com.zaxxer.hikari.pool.Poolbase.newPoolEntry(Poolbase.java:206) at com.zaxxer.hikari.pool.HikariPool.createPoolEntry(HikariPool.java:476) at com.zaxxer.hikari.pool.HikariPool.checkFailFast(HikariPool.java:561) at com.zaxxer.hikari.pool.HikariPool. (HikariPool.java:115) at com.zaxxer.hikari.HikariDataSource.getConnection(HikariDataSource.java:112) at org.springframework.jdbc.datasource.DataSourceUtils.fetchConnection(DataSourceUtils.java:158) at org.springframework.jdbc.datasource.DataSourceUtils.doGetConnection(DataSourceUtils.java:116) at org.springframework.jdbc.datasource.DataSourceUtils.getConnection(DataSourceUtils.java:79) at org.springframework.jdbc.core.JdbcTemplate.execute(JdbcTemplate.java:330) at org.springframework.boot.jdbc.EmbeddedDatabaseConnection.isEmbedded(EmbeddedDatabaseConnection.java:184) at org.springframework.boot.jdbc.init.DataSourcescriptDatabaseInitializer.isEmbeddedDatabase(DataSourcescriptDatabaseInitializer.java:64) at org.springframework.boot.sql.init.AbstractscriptDatabaseInitializer.isEnabled(AbstractscriptDatabaseInitializer.java:87) at org.springframework.boot.sql.init.AbstractscriptDatabaseInitializer.initializeDatabase(AbstractscriptDatabaseInitializer.java:74) at org.springframework.boot.sql.init.AbstractscriptDatabaseInitializer.afterPropertiesSet(AbstractscriptDatabaseInitializer.java:65) at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.invokeInitMethods(AbstractAutowireCapableBeanFactory.java:1845) at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.initializeBean(AbstractAutowireCapableBeanFactory.java:1782) at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.doCreateBean(AbstractAutowireCapableBeanFactory.java:602) at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.createBean(AbstractAutowireCapableBeanFactory.java:524) at org.springframework.beans.factory.support.AbstractBeanFactory.lambda$doGetBean$0(AbstractBeanFactory.java:335) at org.springframework.beans.factory.support.DefaultSingletonBeanRegistry.getSingleton(DefaultSingletonBeanRegistry.java:234) at org.springframework.beans.factory.support.AbstractBeanFactory.doGetBean(AbstractBeanFactory.java:333) at org.springframework.beans.factory.support.AbstractBeanFactory.getBean(AbstractBeanFactory.java:208) at org.springframework.beans.factory.support.AbstractBeanFactory.doGetBean(AbstractBeanFactory.java:322) at org.springframework.beans.factory.support.AbstractBeanFactory.getBean(AbstractBeanFactory.java:208) at org.springframework.beans.factory.support.DefaultListableBeanFactory.preInstantiateSingletons(DefaultListableBeanFactory.java:944) at org.springframework.context.support.AbstractApplicationContext.finishBeanFactoryInitialization(AbstractApplicationContext.java:918) at org.springframework.context.support.AbstractApplicationContext.refresh(AbstractApplicationContext.java:583) at org.springframework.boot.web.servlet.context.ServletWebServerApplicationContext.refresh(ServletWebServerApplicationContext.java:145) at org.springframework.boot.SpringApplication.refresh(SpringApplication.java:754) at org.springframework.boot.SpringApplication.refreshContext(SpringApplication.java:434) at org.springframework.boot.SpringApplication.run(SpringApplication.java:338) at com.abc.wiki.WikiApplication.main(WikiApplication.java:19) at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method) at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:62) at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43) at java.lang.reflect.Method.invoke(Method.java:498) at org.springframework.boot.devtools.restart.RestartLauncher.run(RestartLauncher.java:49) Caused by: com.mysql.cj.exceptions.CJCommunicationsException: Communications link failure The last packet sent successfully to the server was 0 milliseconds ago. The driver has not received any packets from the server. at sun.reflect.NativeConstructorAccessorImpl.newInstance0(Native Method) at sun.reflect.NativeConstructorAccessorImpl.newInstance(NativeConstructorAccessorImpl.java:62) at sun.reflect.DelegatingConstructorAccessorImpl.newInstance(DelegatingConstructorAccessorImpl.java:45) at java.lang.reflect.Constructor.newInstance(Constructor.java:423) at com.mysql.cj.exceptions.ExceptionFactory.createException(ExceptionFactory.java:61) at com.mysql.cj.exceptions.ExceptionFactory.createException(ExceptionFactory.java:105) at com.mysql.cj.exceptions.ExceptionFactory.createException(ExceptionFactory.java:151) at com.mysql.cj.exceptions.ExceptionFactory.createCommunicationsException(ExceptionFactory.java:167) at com.mysql.cj.protocol.a.NativeSocketConnection.connect(NativeSocketConnection.java:89) at com.mysql.cj.NativeSession.connect(NativeSession.java:144) at com.mysql.cj.jdbc.ConnectionImpl.connectOneTryOnly(ConnectionImpl.java:953) at com.mysql.cj.jdbc.ConnectionImpl.createNewIO(ConnectionImpl.java:823) ... 42 common frames omitted Caused by: java.net.ConnectException: Connection timed out: connect at java.net.DualStackPlainSocketImpl.waitForConnect(Native Method) at java.net.DualStackPlainSocketImpl.socketConnect(DualStackPlainSocketImpl.java:85) at java.net.AbstractPlainSocketImpl.doConnect(AbstractPlainSocketImpl.java:350) at java.net.AbstractPlainSocketImpl.connectToAddress(AbstractPlainSocketImpl.java:206) at java.net.AbstractPlainSocketImpl.connect(AbstractPlainSocketImpl.java:188) at java.net.PlainSocketImpl.connect(PlainSocketImpl.java:172) at java.net.SocksSocketImpl.connect(SocksSocketImpl.java:392) at java.net.Socket.connect(Socket.java:589) at com.mysql.cj.protocol.StandardSocketFactory.connect(StandardSocketFactory.java:155) at com.mysql.cj.protocol.a.NativeSocketConnection.connect(NativeSocketConnection.java:63) ... 45 common frames omitted
【问题原因】：今天在本地调试项目，由于电脑连接的wifi变了，导致ip也变了，最终导致这个问题。
【解决方法】：将项目连接数据库的配置修改为新的ip地址。
