连接数据库报错：
java.sql.SQLNonTransientConnectionException: Could not create connection to database server. Attempted reconnect 3 times. Giving up.
at com.mysql.cj.jdbc.exceptions.SQLError.createSQLException(SQLError.java:110) ~[mysql-connector-java-8.0.19.jar:8.0.19]
at com.mysql.cj.jdbc.exceptions.SQLError.createSQLException(SQLError.java:97) ~[mysql-connector-java-8.0.19.jar:8.0.19]
at com.mysql.cj.jdbc.exceptions.SQLError.createSQLException(SQLError.java:89) ~[mysql-connector-java-8.0.19.jar:8.0.19]
at com.mysql.cj.jdbc.exceptions.SQLError.createSQLException(SQLError.java:63) ~[mysql-connector-java-8.0.19.jar:8.0.19]
at com.mysql.cj.jdbc.exceptions.SQLError.createSQLException(SQLError.java:73) ~[mysql-connector-java-8.0.19.jar:8.0.19]
at com.mysql.cj.jdbc.ConnectionImpl.connectWithRetries(ConnectionImpl.java:906) ~[mysql-connector-java-8.0.19.jar:8.0.19]
at com.mysql.cj.jdbc.ConnectionImpl.createNewIO(ConnectionImpl.java:831) ~[mysql-connector-java-8.0.19.jar:8.0.19]
at com.mysql.cj.jdbc.ConnectionImpl.<init>(ConnectionImpl.java:456) ~[mysql-connector-java-8.0.19.jar:8.0.19]
at com.mysql.cj.jdbc.ConnectionImpl.getInstance(ConnectionImpl.java:246) ~[mysql-connector-java-8.0.19.jar:8.0.19]
at com.mysql.cj.jdbc.NonRegisteringDriver.connect(NonRegisteringDriver.java:197) ~[mysql-connector-java-8.0.19.jar:8.0.19]
at com.zaxxer.hikari.util.DriverDataSource.getConnection(DriverDataSource.java:138) ~[HikariCP-3.4.2.jar:na]
at com.zaxxer.hikari.pool.PoolBase.newConnection(PoolBase.java:354) ~[HikariCP-3.4.2.jar:na]
at com.zaxxer.hikari.pool.PoolBase.newPoolEntry(PoolBase.java:202) ~[HikariCP-3.4.2.jar:na]
at com.zaxxer.hikari.pool.HikariPool.createPoolEntry(HikariPool.java:473) [HikariCP-3.4.2.jar:na]
at com.zaxxer.hikari.pool.HikariPool.checkFailFast(HikariPool.java:554) [HikariCP-3.4.2.jar:na]
at com.zaxxer.hikari.pool.HikariPool.<init>(HikariPool.java:115) [HikariCP-3.4.2.jar:na]
at com.zaxxer.hikari.HikariDataSource.getConnection(HikariDataSource.java:112) [HikariCP-3.4.2.jar:na]
at org.springframework.jdbc.datasource.DataSourceUtils.fetchConnection(DataSourceUtils.java:158) [spring-jdbc-5.2.3.RELEASE.jar:5.2.3.RELEASE]
at org.springframework.jdbc.datasource.DataSourceUtils.doGetConnection(DataSourceUtils.java:116) [spring-jdbc-5.2.3.RELEASE.jar:5.2.3.RELEASE]
at org.springframework.jdbc.datasource.DataSourceUtils.getConnection(DataSourceUtils.java:79) [spring-jdbc-5.2.3.RELEASE.jar:5.2.3.RELEASE]
at org.mybatis.spring.transaction.SpringManagedTransaction.openConnection(SpringManagedTransaction.java:82) [mybatis-spring-1.3.2.jar:1.3.2]
at org.mybatis.spring.transaction.SpringManagedTransaction.getConnection(SpringManagedTransaction.java:68) [mybatis-spring-1.3.2.jar:1.3.2]
at org.apache.ibatis.executor.BaseExecutor.getConnection(BaseExecutor.java:338) [mybatis-3.4.6.jar:3.4.6]
at org.apache.ibatis.executor.SimpleExecutor.prepareStatement(SimpleExecutor.java:84) [mybatis-3.4.6.jar:3.4.6]
at org.apache.ibatis.executor.SimpleExecutor.doQuery(SimpleExecutor.java:62) [mybatis-3.4.6.jar:3.4.6]
at org.apache.ibatis.executor.BaseExecutor.queryFromDatabase(BaseExecutor.java:326) [mybatis-3.4.6.jar:3.4.6]
at org.apache.ibatis.executor.BaseExecutor.query(BaseExecutor.java:156) [mybatis-3.4.6.jar:3.4.6]
at org.apache.ibatis.executor.CachingExecutor.query(CachingExecutor.java:109) [mybatis-3.4.6.jar:3.4.6]
at org.apache.ibatis.executor.CachingExecutor.query(CachingExecutor.java:83) [mybatis-3.4.6.jar:3.4.6]
at org.apache.ibatis.session.defaults.DefaultSqlSession.selectList(DefaultSqlSession.java:148) [mybatis-3.4.6.jar:3.4.6]
at org.apache.ibatis.session.defaults.DefaultSqlSession.selectList(DefaultSqlSession.java:141) [mybatis-3.4.6.jar:3.4.6]
at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method) ~[na:1.8.0_92]
at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:62) ~[na:1.8.0_92]
at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43) ~[na:1.8.0_92]
at java.lang.reflect.Method.invoke(Method.java:498) ~[na:1.8.0_92]
at org.mybatis.spring.SqlSessionTemplate$SqlSessionInterceptor.invoke(SqlSessionTemplate.java:433) [mybatis-spring-1.3.2.jar:1.3.2]
at com.sun.proxy.$Proxy68.selectList(Unknown Source) [na:na]
at org.mybatis.spring.SqlSessionTemplate.selectList(SqlSessionTemplate.java:230) [mybatis-spring-1.3.2.jar:1.3.2]
at org.apache.ibatis.binding.MapperMethod.executeForMany(MapperMethod.java:139) [mybatis-3.4.6.jar:3.4.6]
at org.apache.ibatis.binding.MapperMethod.execute(MapperMethod.java:76) [mybatis-3.4.6.jar:3.4.6]
at org.apache.ibatis.binding.MapperProxy.invoke(MapperProxy.java:59) [mybatis-3.4.6.jar:3.4.6]
at com.sun.proxy.$Proxy69.findAll(Unknown Source) [na:na]
at com.yql.mango.service.Impl.SysUserServiceImpl.findAll(SysUserServiceImpl.java:20) [classes/:na]
at com.yql.mango.controller.SysUserController.findAll(SysUserController.java:19) [classes/:na]
at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method) ~[na:1.8.0_92]
at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:62) ~[na:1.8.0_92]
at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43) ~[na:1.8.0_92]
at java.lang.reflect.Method.invoke(Method.java:498) ~[na:1.8.0_92]
at org.springframework.web.method.support.InvocableHandlerMethod.doInvoke(InvocableHandlerMethod.java:190) [spring-web-5.2.3.RELEASE.jar:5.2.3.RELEASE]
at org.springframework.web.method.support.InvocableHandlerMethod.invokeForRequest(InvocableHandlerMethod.java:138) [spring-web-5.2.3.RELEASE.jar:5.2.3.RELEASE]
at org.springframework.web.servlet.mvc.method.annotation.ServletInvocableHandlerMethod.invokeAndHandle(ServletInvocableHandlerMethod.java:106) [spring-webmvc-5.2.3.RELEASE.jar:5.2.3.RELEASE]
at org.springframework.web.servlet.mvc.method.annotation.RequestMappingHandlerAdapter.invokeHandlerMethod(RequestMappingHandlerAdapter.java:888) [spring-webmvc-5.2.3.RELEASE.jar:5.2.3.RELEASE]
at org.springframework.web.servlet.mvc.method.annotation.RequestMappingHandlerAdapter.handleInternal(RequestMappingHandlerAdapter.java:793) [spring-webmvc-5.2.3.RELEASE.jar:5.2.3.RELEASE]
at org.springframework.web.servlet.mvc.method.AbstractHandlerMethodAdapter.handle(AbstractHandlerMethodAdapter.java:87) [spring-webmvc-5.2.3.RELEASE.jar:5.2.3.RELEASE]
at org.springframework.web.servlet.DispatcherServlet.doDispatch(DispatcherServlet.java:1040) [spring-webmvc-5.2.3.RELEASE.jar:5.2.3.RELEASE]
at org.springframework.web.servlet.DispatcherServlet.doService(DispatcherServlet.java:943) [spring-webmvc-5.2.3.RELEASE.jar:5.2.3.RELEASE]
at org.springframework.web.servlet.FrameworkServlet.processRequest(FrameworkServlet.java:1006) [spring-webmvc-5.2.3.RELEASE.jar:5.2.3.RELEASE]
at org.springframework.web.servlet.FrameworkServlet.doGet(FrameworkServlet.java:898) [spring-webmvc-5.2.3.RELEASE.jar:5.2.3.RELEASE]
at javax.servlet.http.HttpServlet.service(HttpServlet.java:634) [tomcat-embed-core-9.0.30.jar:9.0.30]
at org.springframework.web.servlet.FrameworkServlet.service(FrameworkServlet.java:883) [spring-webmvc-5.2.3.RELEASE.jar:5.2.3.RELEASE]
at javax.servlet.http.HttpServlet.service(HttpServlet.java:741) [tomcat-embed-core-9.0.30.jar:9.0.30]
at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:231) [tomcat-embed-core-9.0.30.jar:9.0.30]
at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:166) [tomcat-embed-core-9.0.30.jar:9.0.30]
at org.apache.tomcat.websocket.server.WsFilter.doFilter(WsFilter.java:53) [tomcat-embed-websocket-9.0.30.jar:9.0.30]
at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:193) [tomcat-embed-core-9.0.30.jar:9.0.30]
at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:166) [tomcat-embed-core-9.0.30.jar:9.0.30]
at org.springframework.web.filter.RequestContextFilter.doFilterInternal(RequestContextFilter.java:100) [spring-web-5.2.3.RELEASE.jar:5.2.3.RELEASE]
at org.springframework.web.filter.OncePerRequestFilter.doFilter(OncePerRequestFilter.java:119) [spring-web-5.2.3.RELEASE.jar:5.2.3.RELEASE]
at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:193) [tomcat-embed-core-9.0.30.jar:9.0.30]
at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:166) [tomcat-embed-core-9.0.30.jar:9.0.30]
at org.springframework.web.filter.FormContentFilter.doFilterInternal(FormContentFilter.java:93) [spring-web-5.2.3.RELEASE.jar:5.2.3.RELEASE]
at org.springframework.web.filter.OncePerRequestFilter.doFilter(OncePerRequestFilter.java:119) [spring-web-5.2.3.RELEASE.jar:5.2.3.RELEASE]
at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:193) [tomcat-embed-core-9.0.30.jar:9.0.30]
at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:166) [tomcat-embed-core-9.0.30.jar:9.0.30]
at org.springframework.web.filter.CharacterEncodingFilter.doFilterInternal(CharacterEncodingFilter.java:201) [spring-web-5.2.3.RELEASE.jar:5.2.3.RELEASE]
at org.springframework.web.filter.OncePerRequestFilter.doFilter(OncePerRequestFilter.java:119) [spring-web-5.2.3.RELEASE.jar:5.2.3.RELEASE]
at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:193) [tomcat-embed-core-9.0.30.jar:9.0.30]
at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:166) [tomcat-embed-core-9.0.30.jar:9.0.30]
at org.apache.catalina.core.StandardWrapperValve.invoke(StandardWrapperValve.java:202) [tomcat-embed-core-9.0.30.jar:9.0.30]
at org.apache.catalina.core.StandardContextValve.invoke(StandardContextValve.java:96) [tomcat-embed-core-9.0.30.jar:9.0.30]
at org.apache.catalina.authenticator.AuthenticatorBase.invoke(AuthenticatorBase.java:541) [tomcat-embed-core-9.0.30.jar:9.0.30]
at org.apache.catalina.core.StandardHostValve.invoke(StandardHostValve.java:139) [tomcat-embed-core-9.0.30.jar:9.0.30]
at org.apache.catalina.valves.ErrorReportValve.invoke(ErrorReportValve.java:92) [tomcat-embed-core-9.0.30.jar:9.0.30]
at org.apache.catalina.core.StandardEngineValve.invoke(StandardEngineValve.java:74) [tomcat-embed-core-9.0.30.jar:9.0.30]
at org.apache.catalina.connector.CoyoteAdapter.service(CoyoteAdapter.java:343) [tomcat-embed-core-9.0.30.jar:9.0.30]
at org.apache.coyote.http11.Http11Processor.service(Http11Processor.java:367) [tomcat-embed-core-9.0.30.jar:9.0.30]
at org.apache.coyote.AbstractProcessorLight.process(AbstractProcessorLight.java:65) [tomcat-embed-core-9.0.30.jar:9.0.30]
at org.apache.coyote.AbstractProtocol$ConnectionHandler.process(AbstractProtocol.java:860) [tomcat-embed-core-9.0.30.jar:9.0.30]
at org.apache.tomcat.util.net.NioEndpoint$SocketProcessor.doRun(NioEndpoint.java:1598) [tomcat-embed-core-9.0.30.jar:9.0.30]
at org.apache.tomcat.util.net.SocketProcessorBase.run(SocketProcessorBase.java:49) [tomcat-embed-core-9.0.30.jar:9.0.30]
at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1142) [na:1.8.0_92]
at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:617) [na:1.8.0_92]
at org.apache.tomcat.util.threads.TaskThread$WrappingRunnable.run(TaskThread.java:61) [tomcat-embed-core-9.0.30.jar:9.0.30]
at java.lang.Thread.run(Thread.java:745) [na:1.8.0_92]
Caused by: com.mysql.cj.exceptions.InvalidConnectionAttributeException: The server time zone value '�й���ʱ��' is unrecognized or represents more than one time zone. You must configure either the server or JDBC driver (via the 'serverTimezone' configuration property) to use a more specifc time zone value if you want to utilize time zone support.
at sun.reflect.NativeConstructorAccessorImpl.newInstance0(Native Method) ~[na:1.8.0_92]
at sun.reflect.NativeConstructorAccessorImpl.newInstance(NativeConstructorAccessorImpl.java:62) ~[na:1.8.0_92]
at sun.reflect.DelegatingConstructorAccessorImpl.newInstance(DelegatingConstructorAccessorImpl.java:45) ~[na:1.8.0_92]
at java.lang.reflect.Constructor.newInstance(Constructor.java:423) ~[na:1.8.0_92]
at com.mysql.cj.exceptions.ExceptionFactory.createException(ExceptionFactory.java:61) ~[mysql-connector-java-8.0.19.jar:8.0.19]
at com.mysql.cj.exceptions.ExceptionFactory.createException(ExceptionFactory.java:85) ~[mysql-connector-java-8.0.19.jar:8.0.19]
at com.mysql.cj.util.TimeUtil.getCanonicalTimezone(TimeUtil.java:132) ~[mysql-connector-java-8.0.19.jar:8.0.19]
at com.mysql.cj.protocol.a.NativeProtocol.configureTimezone(NativeProtocol.java:2118) ~[mysql-connector-java-8.0.19.jar:8.0.19]
at com.mysql.cj.protocol.a.NativeProtocol.initServerSession(NativeProtocol.java:2142) ~[mysql-connector-java-8.0.19.jar:8.0.19]
at com.mysql.cj.jdbc.ConnectionImpl.initializePropsFromServer(ConnectionImpl.java:1310) ~[mysql-connector-java-8.0.19.jar:8.0.19]
at com.mysql.cj.jdbc.ConnectionImpl.connectWithRetries(ConnectionImpl.java:869) ~[mysql-connector-java-8.0.19.jar:8.0.19]
... 88 common frames omitted
错误原因：
MySQL jdbc 6.0 版本以上必须配置“serverTimezone”参数
UTC代表的是全球标准时间
修改URL
jdbc:mysql://localhost:3306/mango?characterEncoding=utf-8&serverTimezone=UTC