开始的配置：
url: jdbc:mysql://mysql:3306/heima?useSSL=false
更改后的配置
jdbc:mysql://127.0.0.1:3306/heima?useSSL=false
说白了其实就将其他地址转换为本地机地址
下面是报错，希望对参考有帮助
com.mysql.jdbc.exceptions.jdbc4.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 java.base/jdk.internal.reflect.NativeConstructorAccessorImpl.newInstance0(Native Method) ~[na:na]
at java.base/jdk.internal.reflect.NativeConstructorAccessorImpl.newInstance(NativeConstructorAccessorImpl.java:64) ~[na:na]
at java.base/jdk.internal.reflect.DelegatingConstructorAccessorImpl.newInstance(DelegatingConstructorAccessorImpl.java:45) ~[na:na]
at java.base/java.lang.reflect.Constructor.newInstanceWithCaller(Constructor.java:500) ~[na:na]
at java.base/java.lang.reflect.Constructor.newInstance(Constructor.java:481) ~[na:na]
at com.mysql.jdbc.Util.handleNewInstance(Util.java:411) ~[mysql-connector-java-5.1.21.jar:na]
at com.mysql.jdbc.SQLError.createCommunicationsException(SQLError.java:1117) ~[mysql-connector-java-5.1.21.jar:na]
at com.mysql.jdbc.MysqlIO.
at com.mysql.jdbc.ConnectionImpl.coreConnect(ConnectionImpl.java:2393) ~[mysql-connector-java-5.1.21.jar:na]
at com.mysql.jdbc.ConnectionImpl.connectOneTryOnly(ConnectionImpl.java:2430) ~[mysql-connector-java-5.1.21.jar:na]
at com.mysql.jdbc.ConnectionImpl.createNewIO(ConnectionImpl.java:2215) ~[mysql-connector-java-5.1.21.jar:na]
at com.mysql.jdbc.ConnectionImpl.
at com.mysql.jdbc.JDBC4Connection.
at java.base/jdk.internal.reflect.NativeConstructorAccessorImpl.newInstance0(Native Method) ~[na:na]
at java.base/jdk.internal.reflect.NativeConstructorAccessorImpl.newInstance(NativeConstructorAccessorImpl.java:64) ~[na:na]
at java.base/jdk.internal.reflect.DelegatingConstructorAccessorImpl.newInstance(DelegatingConstructorAccessorImpl.java:45) ~[na:na]
at java.base/java.lang.reflect.Constructor.newInstanceWithCaller(Constructor.java:500) ~[na:na]
at java.base/java.lang.reflect.Constructor.newInstance(Constructor.java:481) ~[na:na]
at com.mysql.jdbc.Util.handleNewInstance(Util.java:411) ~[mysql-connector-java-5.1.21.jar:na]
at com.mysql.jdbc.ConnectionImpl.getInstance(ConnectionImpl.java:399) ~[mysql-connector-java-5.1.21.jar:na]
at com.mysql.jdbc.NonRegisteringDriver.connect(NonRegisteringDriver.java:334) ~[mysql-connector-java-5.1.21.jar:na]
at com.zaxxer.hikari.util.DriverDataSource.getConnection(DriverDataSource.java:138) ~[HikariCP-3.4.5.jar:na]
at com.zaxxer.hikari.pool.PoolBase.newConnection(PoolBase.java:358) ~[HikariCP-3.4.5.jar:na]
at com.zaxxer.hikari.pool.PoolBase.newPoolEntry(PoolBase.java:206) ~[HikariCP-3.4.5.jar:na]
at com.zaxxer.hikari.pool.HikariPool.createPoolEntry(HikariPool.java:477) ~[HikariCP-3.4.5.jar:na]
at com.zaxxer.hikari.pool.HikariPool.checkFailFast(HikariPool.java:560) ~[HikariCP-3.4.5.jar:na]
at com.zaxxer.hikari.pool.HikariPool.
at com.zaxxer.hikari.HikariDataSource.getConnection(HikariDataSource.java:112) ~[HikariCP-3.4.5.jar:na]
at org.springframework.jdbc.datasource.DataSourceUtils.fetchConnection(DataSourceUtils.java:158) ~[spring-jdbc-5.2.14.RELEASE.jar:5.2.14.RELEASE]
at org.springframework.jdbc.datasource.DataSourceUtils.doGetConnection(DataSourceUtils.java:116) ~[spring-jdbc-5.2.14.RELEASE.jar:5.2.14.RELEASE]
at org.springframework.jdbc.datasource.DataSourceUtils.getConnection(DataSourceUtils.java:79) ~[spring-jdbc-5.2.14.RELEASE.jar:5.2.14.RELEASE]
at org.mybatis.spring.transaction.SpringManagedTransaction.openConnection(SpringManagedTransaction.java:80) ~[mybatis-spring-2.0.5.jar:2.0.5]
at org.mybatis.spring.transaction.SpringManagedTransaction.getConnection(SpringManagedTransaction.java:67) ~[mybatis-spring-2.0.5.jar:2.0.5]
at org.apache.ibatis.executor.BaseExecutor.getConnection(BaseExecutor.java:337) ~[mybatis-3.5.6.jar:3.5.6]
at com.baomidou.mybatisplus.core.executor.MybatisSimpleExecutor.prepareStatement(MybatisSimpleExecutor.java:93) ~[mybatis-plus-core-3.4.2.jar:3.4.2]
at com.baomidou.mybatisplus.core.executor.MybatisSimpleExecutor.doQuery(MybatisSimpleExecutor.java:68) ~[mybatis-plus-core-3.4.2.jar:3.4.2]
at org.apache.ibatis.executor.BaseExecutor.queryFromDatabase(BaseExecutor.java:325) ~[mybatis-3.5.6.jar:3.5.6]
at org.apache.ibatis.executor.BaseExecutor.query(BaseExecutor.java:156) ~[mybatis-3.5.6.jar:3.5.6]
at com.baomidou.mybatisplus.core.executor.MybatisCachingExecutor.query(MybatisCachingExecutor.java:165) ~[mybatis-plus-core-3.4.2.jar:3.4.2]
at com.baomidou.mybatisplus.extension.plugins.inner.PaginationInnerInterceptor.willDoQuery(PaginationInnerInterceptor.java:141) ~[mybatis-plus-extension-3.4.2.jar:3.4.2]
at com.baomidou.mybatisplus.extension.plugins.MybatisPlusInterceptor.intercept(MybatisPlusInterceptor.java:75) ~[mybatis-plus-extension-3.4.2.jar:3.4.2]
at org.apache.ibatis.plugin.Plugin.invoke(Plugin.java:61) ~[mybatis-3.5.6.jar:3.5.6]
at com.sun.proxy.$Proxy74.query(Unknown Source) ~[na:na]
at org.apache.ibatis.session.defaults.DefaultSqlSession.selectList(DefaultSqlSession.java:147) ~[mybatis-3.5.6.jar:3.5.6]
at org.apache.ibatis.session.defaults.DefaultSqlSession.selectList(DefaultSqlSession.java:140) ~[mybatis-3.5.6.jar:3.5.6]
at java.base/jdk.internal.reflect.NativeMethodAccessorImpl.invoke0(Native Method) ~[na:na]
at java.base/jdk.internal.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:64) ~[na:na]
at java.base/jdk.internal.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43) ~[na:na]
at java.base/java.lang.reflect.Method.invoke(Method.java:564) ~[na:na]
at org.mybatis.spring.SqlSessionTemplate$SqlSessionInterceptor.invoke(SqlSessionTemplate.java:426) ~[mybatis-spring-2.0.5.jar:2.0.5]
at com.sun.proxy.$Proxy54.selectList(Unknown Source) ~[na:na]
at org.mybatis.spring.SqlSessionTemplate.selectList(SqlSessionTemplate.java:223) ~[mybatis-spring-2.0.5.jar:2.0.5]
at com.baomidou.mybatisplus.core.override.MybatisMapperMethod.executeForIPage(MybatisMapperMethod.java:122) ~[mybatis-plus-core-3.4.2.jar:3.4.2]
at com.baomidou.mybatisplus.core.override.MybatisMapperMethod.execute(MybatisMapperMethod.java:86) ~[mybatis-plus-core-3.4.2.jar:3.4.2]
at com.baomidou.mybatisplus.core.override.MybatisMapperProxy$PlainMethodInvoker.invoke(MybatisMapperProxy.java:148) ~[mybatis-plus-core-3.4.2.jar:3.4.2]
at com.baomidou.mybatisplus.core.override.MybatisMapperProxy.invoke(MybatisMapperProxy.java:89) ~[mybatis-plus-core-3.4.2.jar:3.4.2]
at com.sun.proxy.$Proxy56.selectPage(Unknown Source) ~[na:na]
at com.baomidou.mybatisplus.extension.service.IService.page(IService.java:298) ~[mybatis-plus-extension-3.4.2.jar:3.4.2]
at com.baomidou.mybatisplus.extension.service.IService.page(IService.java:308) ~[mybatis-plus-extension-3.4.2.jar:3.4.2]
at com.baomidou.mybatisplus.extension.service.IService$$FastClassBySpringCGLIB$$f8525d18.invoke(
at org.springframework.cglib.proxy.MethodProxy.invoke(MethodProxy.java:218) ~[spring-core-5.2.14.RELEASE.jar:5.2.14.RELEASE]
at org.springframework.aop.framework.CglibAopProxy$DynamicAdvisedInterceptor.intercept(CglibAopProxy.java:687) ~[spring-aop-5.2.14.RELEASE.jar:5.2.14.RELEASE]
at cn.itcast.hotel.service.impl.HotelService$$EnhancerBySpringCGLIB$$993fe1ac.page(
at cn.itcast.hotel.web.HotelController.hotelList(HotelController.java:29) ~[classes/:na]
at java.base/jdk.internal.reflect.NativeMethodAccessorImpl.invoke0(Native Method) ~[na:na]
at java.base/jdk.internal.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:64) ~[na:na]
at java.base/jdk.internal.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43) ~[na:na]
at java.base/java.lang.reflect.Method.invoke(Method.java:564) ~[na:na]
at org.springframework.web.method.support.InvocableHandlerMethod.doInvoke(InvocableHandlerMethod.java:190) ~[spring-web-5.2.14.RELEASE.jar:5.2.14.RELEASE]
at org.springframework.web.method.support.InvocableHandlerMethod.invokeForRequest(InvocableHandlerMethod.java:138) ~[spring-web-5.2.14.RELEASE.jar:5.2.14.RELEASE]
at org.springframework.web.servlet.mvc.method.annotation.ServletInvocableHandlerMethod.invokeAndHandle(ServletInvocableHandlerMethod.java:105) ~[spring-webmvc-5.2.14.RELEASE.jar:5.2.14.RELEASE]
at org.springframework.web.servlet.mvc.method.annotation.RequestMappingHandlerAdapter.invokeHandlerMethod(RequestMappingHandlerAdapter.java:878) ~[spring-webmvc-5.2.14.RELEASE.jar:5.2.14.RELEASE]
at org.springframework.web.servlet.mvc.method.annotation.RequestMappingHandlerAdapter.handleInternal(RequestMappingHandlerAdapter.java:792) ~[spring-webmvc-5.2.14.RELEASE.jar:5.2.14.RELEASE]
at org.springframework.web.servlet.mvc.method.AbstractHandlerMethodAdapter.handle(AbstractHandlerMethodAdapter.java:87) ~[spring-webmvc-5.2.14.RELEASE.jar:5.2.14.RELEASE]
at org.springframework.web.servlet.DispatcherServlet.doDispatch(DispatcherServlet.java:1040) ~[spring-webmvc-5.2.14.RELEASE.jar:5.2.14.RELEASE]
at org.springframework.web.servlet.DispatcherServlet.doService(DispatcherServlet.java:943) ~[spring-webmvc-5.2.14.RELEASE.jar:5.2.14.RELEASE]
at org.springframework.web.servlet.FrameworkServlet.processRequest(FrameworkServlet.java:1006) ~[spring-webmvc-5.2.14.RELEASE.jar:5.2.14.RELEASE]
at org.springframework.web.servlet.FrameworkServlet.doGet(FrameworkServlet.java:898) ~[spring-webmvc-5.2.14.RELEASE.jar:5.2.14.RELEASE]
at javax.servlet.http.HttpServlet.service(HttpServlet.java:626) ~[tomcat-embed-core-9.0.45.jar:4.0.FR]
at org.springframework.web.servlet.FrameworkServlet.service(FrameworkServlet.java:883) ~[spring-webmvc-5.2.14.RELEASE.jar:5.2.14.RELEASE]
at javax.servlet.http.HttpServlet.service(HttpServlet.java:733) ~[tomcat-embed-core-9.0.45.jar:4.0.FR]
at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:227) ~[tomcat-embed-core-9.0.45.jar:9.0.45]
at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:162) ~[tomcat-embed-core-9.0.45.jar:9.0.45]
at org.apache.tomcat.websocket.server.WsFilter.doFilter(WsFilter.java:53) ~[tomcat-embed-websocket-9.0.45.jar:9.0.45]
at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:189) ~[tomcat-embed-core-9.0.45.jar:9.0.45]
at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:162) ~[tomcat-embed-core-9.0.45.jar:9.0.45]
at org.springframework.web.filter.RequestContextFilter.doFilterInternal(RequestContextFilter.java:100) ~[spring-web-5.2.14.RELEASE.jar:5.2.14.RELEASE]
at org.springframework.web.filter.OncePerRequestFilter.doFilter(OncePerRequestFilter.java:119) ~[spring-web-5.2.14.RELEASE.jar:5.2.14.RELEASE]
at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:189) ~[tomcat-embed-core-9.0.45.jar:9.0.45]
at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:162) ~[tomcat-embed-core-9.0.45.jar:9.0.45]
at org.springframework.web.filter.FormContentFilter.doFilterInternal(FormContentFilter.java:93) ~[spring-web-5.2.14.RELEASE.jar:5.2.14.RELEASE]
at org.springframework.web.filter.OncePerRequestFilter.doFilter(OncePerRequestFilter.java:119) ~[spring-web-5.2.14.RELEASE.jar:5.2.14.RELEASE]
at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:189) ~[tomcat-embed-core-9.0.45.jar:9.0.45]
at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:162) ~[tomcat-embed-core-9.0.45.jar:9.0.45]
at org.springframework.web.filter.CharacterEncodingFilter.doFilterInternal(CharacterEncodingFilter.java:201) ~[spring-web-5.2.14.RELEASE.jar:5.2.14.RELEASE]
at org.springframework.web.filter.OncePerRequestFilter.doFilter(OncePerRequestFilter.java:119) ~[spring-web-5.2.14.RELEASE.jar:5.2.14.RELEASE]
at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:189) ~[tomcat-embed-core-9.0.45.jar:9.0.45]
at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:162) ~[tomcat-embed-core-9.0.45.jar:9.0.45]
at org.apache.catalina.core.StandardWrapperValve.invoke(StandardWrapperValve.java:202) ~[tomcat-embed-core-9.0.45.jar:9.0.45]
at org.apache.catalina.core.StandardContextValve.invoke(StandardContextValve.java:97) ~[tomcat-embed-core-9.0.45.jar:9.0.45]
at org.apache.catalina.authenticator.AuthenticatorBase.invoke(AuthenticatorBase.java:542) ~[tomcat-embed-core-9.0.45.jar:9.0.45]
at org.apache.catalina.core.StandardHostValve.invoke(StandardHostValve.java:143) ~[tomcat-embed-core-9.0.45.jar:9.0.45]
at org.apache.catalina.valves.ErrorReportValve.invoke(ErrorReportValve.java:92) ~[tomcat-embed-core-9.0.45.jar:9.0.45]
at org.apache.catalina.core.StandardEngineValve.invoke(StandardEngineValve.java:78) ~[tomcat-embed-core-9.0.45.jar:9.0.45]
at org.apache.catalina.connector.CoyoteAdapter.service(CoyoteAdapter.java:357) ~[tomcat-embed-core-9.0.45.jar:9.0.45]
at org.apache.coyote.http11.Http11Processor.service(Http11Processor.java:374) ~[tomcat-embed-core-9.0.45.jar:9.0.45]
at org.apache.coyote.AbstractProcessorLight.process(AbstractProcessorLight.java:65) ~[tomcat-embed-core-9.0.45.jar:9.0.45]
at org.apache.coyote.AbstractProtocol$ConnectionHandler.process(AbstractProtocol.java:893) ~[tomcat-embed-core-9.0.45.jar:9.0.45]
at org.apache.tomcat.util.net.NioEndpoint$SocketProcessor.doRun(NioEndpoint.java:1707) ~[tomcat-embed-core-9.0.45.jar:9.0.45]
at org.apache.tomcat.util.net.SocketProcessorBase.run(SocketProcessorBase.java:49) ~[tomcat-embed-core-9.0.45.jar:9.0.45]
at java.base/java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1130) ~[na:na]
at java.base/java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:630) ~[na:na]
at org.apache.tomcat.util.threads.TaskThread$WrappingRunnable.run(TaskThread.java:61) ~[tomcat-embed-core-9.0.45.jar:9.0.45]
at java.base/java.lang.Thread.run(Thread.java:832) ~[na:na]
Caused by: java.net.UnknownHostException: 不知道这样的主机。 (mysql)
at java.base/java.net.Inet6AddressImpl.lookupAllHostAddr(Native Method) ~[na:na]
at java.base/java.net.InetAddress$PlatformNameService.lookupAllHostAddr(InetAddress.java:932) ~[na:na]
at java.base/java.net.InetAddress.getAddressesFromNameService(InetAddress.java:1517) ~[na:na]
at java.base/java.net.InetAddress$NameServiceAddresses.get(InetAddress.java:851) ~[na:na]
at java.base/java.net.InetAddress.getAllByName0(InetAddress.java:1507) ~[na:na]
at java.base/java.net.InetAddress.getAllByName(InetAddress.java:1366) ~[na:na]
at java.base/java.net.InetAddress.getAllByName(InetAddress.java:1300) ~[na:na]
at com.mysql.jdbc.StandardSocketFactory.connect(StandardSocketFactory.java:247) ~[mysql-connector-java-5.1.21.jar:na]
at com.mysql.jdbc.MysqlIO.
... 106 common frames omitted
