spring boot项目报错
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 sun.reflect.NativeConstructorAccessorImpl.newInstance0(Native Method) ~[na:1.8.0_152]
at sun.reflect.NativeConstructorAccessorImpl.newInstance(NativeConstructorAccessorImpl.java:62) ~[na:1.8.0_152]
at sun.reflect.DelegatingConstructorAccessorImpl.newInstance(DelegatingConstructorAccessorImpl.java:45) ~[na:1.8.0_152]
at java.lang.reflect.Constructor.newInstance(Constructor.java:423) ~[na:1.8.0_152]
at com.mysql.jdbc.Util.handleNewInstance(Util.java:409) ~[mysql-connector-java-5.1.30.jar:na]
at com.mysql.jdbc.SQLError.createCommunicationsException(SQLError.java:1127) ~[mysql-connector-java-5.1.30.jar:na]
at com.mysql.jdbc.MysqlIO.<init>(MysqlIO.java:356) ~[mysql-connector-java-5.1.30.jar:na]
at com.mysql.jdbc.ConnectionImpl.coreConnect(ConnectionImpl.java:2502) ~[mysql-connector-java-5.1.30.jar:na]
at com.mysql.jdbc.ConnectionImpl.connectOneTryOnly(ConnectionImpl.java:2539) ~[mysql-connector-java-5.1.30.jar:na]
at com.mysql.jdbc.ConnectionImpl.createNewIO(ConnectionImpl.java:2321) ~[mysql-connector-java-5.1.30.jar:na]
at com.mysql.jdbc.ConnectionImpl.<init>(ConnectionImpl.java:832) ~[mysql-connector-java-5.1.30.jar:na]
at com.mysql.jdbc.JDBC4Connection.<init>(JDBC4Connection.java:46) ~[mysql-connector-java-5.1.30.jar:na]
at sun.reflect.NativeConstructorAccessorImpl.newInstance0(Native Method) ~[na:1.8.0_152]
at sun.reflect.NativeConstructorAccessorImpl.newInstance(NativeConstructorAccessorImpl.java:62) ~[na:1.8.0_152]
at sun.reflect.DelegatingConstructorAccessorImpl.newInstance(DelegatingConstructorAccessorImpl.java:45) ~[na:1.8.0_152]
at java.lang.reflect.Constructor.newInstance(Constructor.java:423) ~[na:1.8.0_152]
at com.mysql.jdbc.Util.handleNewInstance(Util.java:409) ~[mysql-connector-java-5.1.30.jar:na]
at com.mysql.jdbc.ConnectionImpl.getInstance(ConnectionImpl.java:417) ~[mysql-connector-java-5.1.30.jar:na]
at com.mysql.jdbc.NonRegisteringDriver.connect(NonRegisteringDriver.java:344) ~[mysql-connector-java-5.1.30.jar:na]
at org.apache.tomcat.jdbc.pool.PooledConnection.connectUsingDriver(PooledConnection.java:310) ~[tomcat-jdbc-8.5.27.jar:na]
at org.apache.tomcat.jdbc.pool.PooledConnection.connect(PooledConnection.java:203) ~[tomcat-jdbc-8.5.27.jar:na]
at org.apache.tomcat.jdbc.pool.ConnectionPool.createConnection(ConnectionPool.java:735) [tomcat-jdbc-8.5.27.jar:na]
at org.apache.tomcat.jdbc.pool.ConnectionPool.borrowConnection(ConnectionPool.java:667) [tomcat-jdbc-8.5.27.jar:na]
at org.apache.tomcat.jdbc.pool.ConnectionPool.init(ConnectionPool.java:482) [tomcat-jdbc-8.5.27.jar:na]
at org.apache.tomcat.jdbc.pool.ConnectionPool.<init>(ConnectionPool.java:154) [tomcat-jdbc-8.5.27.jar:na]
at org.apache.tomcat.jdbc.pool.DataSourceProxy.pCreatePool(DataSourceProxy.java:118) [tomcat-jdbc-8.5.27.jar:na]
at org.apache.tomcat.jdbc.pool.DataSourceProxy.createPool(DataSourceProxy.java:107) [tomcat-jdbc-8.5.27.jar:na]
at org.apache.tomcat.jdbc.pool.DataSourceProxy.getConnection(DataSourceProxy.java:131) [tomcat-jdbc-8.5.27.jar:na]
at org.springframework.jdbc.datasource.DataSourceUtils.doGetConnection(DataSourceUtils.java:111) [spring-jdbc-4.3.14.RELEASE.jar:4.3.14.RELEASE]
at org.springframework.jdbc.datasource.TransactionAwareDataSourceProxy$TransactionAwareInvocationHandler.invoke(TransactionAwareDataSourceProxy.java:225) [spring-jdbc-4.3.14.RELEASE.jar:4.3.14.RELEASE]
at com.sun.proxy.$Proxy82.getMetaData(Unknown Source) [na:na]
at org.activiti.engine.impl.cfg.ProcessEngineConfigurationImpl.initDatabaseType(ProcessEngineConfigurationImpl.java:859) [activiti-engine-5.22.0.jar:5.22.0]
at org.activiti.engine.impl.cfg.ProcessEngineConfigurationImpl.initDataSource(ProcessEngineConfigurationImpl.java:808) [activiti-engine-5.22.0.jar:5.22.0]
at org.activiti.engine.impl.cfg.ProcessEngineConfigurationImpl.init(ProcessEngineConfigurationImpl.java:624) [activiti-engine-5.22.0.jar:5.22.0]
at org.activiti.engine.impl.cfg.ProcessEngineConfigurationImpl.buildProcessEngine(ProcessEngineConfigurationImpl.java:612) [activiti-engine-5.22.0.jar:5.22.0]
at org.activiti.spring.SpringProcessEngineConfiguration.buildProcessEngine(SpringProcessEngineConfiguration.java:65) [activiti-spring-5.22.0.jar:5.22.0]
at org.activiti.spring.ProcessEngineFactoryBean.getObject(ProcessEngineFactoryBean.java:60) [activiti-spring-5.22.0.jar:5.22.0]
at org.activiti.spring.ProcessEngineFactoryBean.getObject(ProcessEngineFactoryBean.java:32) [activiti-spring-5.22.0.jar:5.22.0]
at org.springframework.beans.factory.support.FactoryBeanRegistrySupport.doGetObjectFromFactoryBean(FactoryBeanRegistrySupport.java:168) [spring-beans-4.3.14.RELEASE.jar:4.3.14.RELEASE]
at org.springframework.beans.factory.support.FactoryBeanRegistrySupport.getObjectFromFactoryBean(FactoryBeanRegistrySupport.java:103) [spring-beans-4.3.14.RELEASE.jar:4.3.14.RELEASE]
at org.springframework.beans.factory.support.AbstractBeanFactory.getObjectForBeanInstance(AbstractBeanFactory.java:1634) [spring-beans-4.3.14.RELEASE.jar:4.3.14.RELEASE]
at org.springframework.beans.factory.support.AbstractBeanFactory.doGetBean(AbstractBeanFactory.java:317) [spring-beans-4.3.14.RELEASE.jar:4.3.14.RELEASE]
at org.springframework.beans.factory.support.AbstractBeanFactory.getBean(AbstractBeanFactory.java:202) [spring-beans-4.3.14.RELEASE.jar:4.3.14.RELEASE]
at org.springframework.beans.factory.config.DependencyDescriptor.resolveCandidate(DependencyDescriptor.java:208) [spring-beans-4.3.14.RELEASE.jar:4.3.14.RELEASE]
at org.springframework.beans.factory.support.DefaultListableBeanFactory.doResolveDependency(DefaultListableBeanFactory.java:1138) [spring-beans-4.3.14.RELEASE.jar:4.3.14.RELEASE]
at org.springframework.beans.factory.support.DefaultListableBeanFactory.resolveDependency(DefaultListableBeanFactory.java:1066) [spring-beans-4.3.14.RELEASE.jar:4.3.14.RELEASE]
at org.springframework.beans.factory.support.ConstructorResolver.resolveAutowiredArgument(ConstructorResolver.java:835) [spring-beans-4.3.14.RELEASE.jar:4.3.14.RELEASE]
at org.springframework.beans.factory.support.ConstructorResolver.createArgumentArray(ConstructorResolver.java:741) [spring-beans-4.3.14.RELEASE.jar:4.3.14.RELEASE]
at org.springframework.beans.factory.support.ConstructorResolver.instantiateUsingFactoryMethod(ConstructorResolver.java:467) [spring-beans-4.3.14.RELEASE.jar:4.3.14.RELEASE]
at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.instantiateUsingFactoryMethod(AbstractAutowireCapableBeanFactory.java:1173) [spring-beans-4.3.14.RELEASE.jar:4.3.14.RELEASE]
at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.createBeanInstance(AbstractAutowireCapableBeanFactory.java:1067) [spring-beans-4.3.14.RELEASE.jar:4.3.14.RELEASE]
at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.doCreateBean(AbstractAutowireCapableBeanFactory.java:513) [spring-beans-4.3.14.RELEASE.jar:4.3.14.RELEASE]
at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.createBean(AbstractAutowireCapableBeanFactory.java:483) [spring-beans-4.3.14.RELEASE.jar:4.3.14.RELEASE]
at org.springframework.beans.factory.support.AbstractBeanFactory$1.getObject(AbstractBeanFactory.java:306) [spring-beans-4.3.14.RELEASE.jar:4.3.14.RELEASE]
at org.springframework.beans.factory.support.DefaultSingletonBeanRegistry.getSingleton(DefaultSingletonBeanRegistry.java:230) [spring-beans-4.3.14.RELEASE.jar:4.3.14.RELEASE]
at org.springframework.beans.factory.support.AbstractBeanFactory.doGetBean(AbstractBeanFactory.java:302) [spring-beans-4.3.14.RELEASE.jar:4.3.14.RELEASE]
at org.springframework.beans.factory.support.AbstractBeanFactory.getBean(AbstractBeanFactory.java:202) [spring-beans-4.3.14.RELEASE.jar:4.3.14.RELEASE]
at org.springframework.beans.factory.config.DependencyDescriptor.resolveCandidate(DependencyDescriptor.java:208) [spring-beans-4.3.14.RELEASE.jar:4.3.14.RELEASE]
at org.springframework.beans.factory.support.DefaultListableBeanFactory.doResolveDependency(DefaultListableBeanFactory.java:1138) [spring-beans-4.3.14.RELEASE.jar:4.3.14.RELEASE]
at org.springframework.beans.factory.support.DefaultListableBeanFactory.resolveDependency(DefaultListableBeanFactory.java:1066) [spring-beans-4.3.14.RELEASE.jar:4.3.14.RELEASE]
at org.springframework.beans.factory.annotation.AutowiredAnnotationBeanPostProcessor$AutowiredFieldElement.inject(AutowiredAnnotationBeanPostProcessor.java:585) [spring-beans-4.3.14.RELEASE.jar:4.3.14.RELEASE]
at org.springframework.beans.factory.annotation.InjectionMetadata.inject(InjectionMetadata.java:88) [spring-beans-4.3.14.RELEASE.jar:4.3.14.RELEASE]
at org.springframework.beans.factory.annotation.AutowiredAnnotationBeanPostProcessor.postProcessPropertyValues(AutowiredAnnotationBeanPostProcessor.java:366) [spring-beans-4.3.14.RELEASE.jar:4.3.14.RELEASE]
at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.populateBean(AbstractAutowireCapableBeanFactory.java:1264) [spring-beans-4.3.14.RELEASE.jar:4.3.14.RELEASE]
at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.doCreateBean(AbstractAutowireCapableBeanFactory.java:553) [spring-beans-4.3.14.RELEASE.jar:4.3.14.RELEASE]
at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.createBean(AbstractAutowireCapableBeanFactory.java:483) [spring-beans-4.3.14.RELEASE.jar:4.3.14.RELEASE]
at org.springframework.beans.factory.support.AbstractBeanFactory$1.getObject(AbstractBeanFactory.java:306) [spring-beans-4.3.14.RELEASE.jar:4.3.14.RELEASE]
at org.springframework.beans.factory.support.DefaultSingletonBeanRegistry.getSingleton(DefaultSingletonBeanRegistry.java:230) [spring-beans-4.3.14.RELEASE.jar:4.3.14.RELEASE]
at org.springframework.beans.factory.support.AbstractBeanFactory.doGetBean(AbstractBeanFactory.java:302) [spring-beans-4.3.14.RELEASE.jar:4.3.14.RELEASE]
at org.springframework.beans.factory.support.AbstractBeanFactory.getBean(AbstractBeanFactory.java:197) [spring-beans-4.3.14.RELEASE.jar:4.3.14.RELEASE]
at org.springframework.beans.factory.support.DefaultListableBeanFactory.preInstantiateSingletons(DefaultListableBeanFactory.java:761) [spring-beans-4.3.14.RELEASE.jar:4.3.14.RELEASE]
at org.springframework.context.support.AbstractApplicationContext.finishBeanFactoryInitialization(AbstractApplicationContext.java:867) [spring-context-4.3.14.RELEASE.jar:4.3.14.RELEASE]
at org.springframework.context.support.AbstractApplicationContext.refresh(AbstractApplicationContext.java:543) [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 boot.spring.Application.main(Application.java:15) [classes/:na]
Caused by: java.net.ConnectException: Connection timed out: connect
at java.net.DualStackPlainSocketImpl.connect0(Native Method) ~[na:1.8.0_152]
at java.net.DualStackPlainSocketImpl.socketConnect(DualStackPlainSocketImpl.java:79) ~[na:1.8.0_152]
at java.net.AbstractPlainSocketImpl.doConnect(AbstractPlainSocketImpl.java:350) ~[na:1.8.0_152]
at java.net.AbstractPlainSocketImpl.connectToAddress(AbstractPlainSocketImpl.java:206) ~[na:1.8.0_152]
at java.net.AbstractPlainSocketImpl.connect(AbstractPlainSocketImpl.java:188) ~[na:1.8.0_152]
at java.net.PlainSocketImpl.connect(PlainSocketImpl.java:172) ~[na:1.8.0_152]
at java.net.SocksSocketImpl.connect(SocksSocketImpl.java:392) ~[na:1.8.0_152]
at java.net.Socket.connect(Socket.java:589) ~[na:1.8.0_152]
at java.net.Socket.connect(Socket.java:538) ~[na:1.8.0_152]
at java.net.Socket.<init>(Socket.java:434) ~[na:1.8.0_152]
at java.net.Socket.<init>(Socket.java:244) ~[na:1.8.0_152]
at com.mysql.jdbc.StandardSocketFactory.connect(StandardSocketFactory.java:258) ~[mysql-connector-java-5.1.30.jar:na]
at com.mysql.jdbc.MysqlIO.<init>(MysqlIO.java:306) ~[mysql-connector-java-5.1.30.jar:na]
... 73 common frames omitted
解决方法：
①注意application.properties中关于数据库的配置置否正确
②链接数据库的url后添加useSSL=false
