连接超时Spring Boot应用程序和MySQL

Question

I'm developing some java (spring-boot) RestFul web-services that using mysql like relational database. Now sometimes I'm getting the following exception:

    com.mysql.jdbc.exceptions.jdbc4.CommunicationsException: Communications link failure

The last packet successfully received from the server was 3,519,805 milliseconds ago.  The last packet sent successfully to the server was 925,623 milliseconds ago.
        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.jdbc.Util.handleNewInstance(Util.java:425)
        at com.mysql.jdbc.SQLError.createCommunicationsException(SQLError.java:989)
        at com.mysql.jdbc.MysqlIO.reuseAndReadPacket(MysqlIO.java:3559)
        at com.mysql.jdbc.MysqlIO.reuseAndReadPacket(MysqlIO.java:3459)
        at com.mysql.jdbc.MysqlIO.checkErrorPacket(MysqlIO.java:3900)
        at com.mysql.jdbc.MysqlIO.sendCommand(MysqlIO.java:2527)
        at com.mysql.jdbc.MysqlIO.sqlQueryDirect(MysqlIO.java:2680)
        at com.mysql.jdbc.ConnectionImpl.execSQL(ConnectionImpl.java:2483)
        at com.mysql.jdbc.ConnectionImpl.execSQL(ConnectionImpl.java:2441)
        at com.mysql.jdbc.StatementImpl.executeInternal(StatementImpl.java:845)
        at com.mysql.jdbc.StatementImpl.execute(StatementImpl.java:745)
        at org.apache.tomcat.jdbc.pool.PooledConnection.validate(PooledConnection.java:532)
        at org.apache.tomcat.jdbc.pool.PooledConnection.validate(PooledConnection.java:443)
        at org.apache.tomcat.jdbc.pool.ConnectionPool.borrowConnection(ConnectionPool.java:802)
        at org.apache.tomcat.jdbc.pool.ConnectionPool.borrowConnection(ConnectionPool.java:651)
        at org.apache.tomcat.jdbc.pool.ConnectionPool.getConnection(ConnectionPool.java:198)
        at org.apache.tomcat.jdbc.pool.DataSourceProxy.getConnection(DataSourceProxy.java:132)
        at org.hibernate.engine.jdbc.connections.internal.DatasourceConnectionProviderImpl.getConnection(DatasourceConnectionProviderImpl.java:122)
        at org.hibernate.internal.AbstractSessionImpl$NonContextualJdbcConnectionAccess.obtainConnection(AbstractSessionImpl.java:386)
        at org.hibernate.resource.jdbc.internal.LogicalConnectionManagedImpl.acquireConnectionIfNeeded(LogicalConnectionManagedImpl.java:87)
        at org.hibernate.resource.jdbc.internal.LogicalConnectionManagedImpl.getPhysicalConnection(LogicalConnectionManagedImpl.java:112)
        at org.hibernate.engine.jdbc.internal.StatementPreparerImpl.connection(StatementPreparerImpl.java:47)
        at org.hibernate.engine.jdbc.internal.StatementPreparerImpl$5.doPrepare(StatementPreparerImpl.java:146)
        at org.hibernate.engine.jdbc.internal.StatementPreparerImpl$StatementPreparationTemplate.prepareStatement(StatementPreparerImpl.java:172)
        at org.hibernate.engine.jdbc.internal.StatementPreparerImpl.prepareQueryStatement(StatementPreparerImpl.java:148)
        at org.hibernate.loader.Loader.prepareQueryStatement(Loader.java:1928)
        at org.hibernate.loader.Loader.executeQueryStatement(Loader.java:1897)
        at org.hibernate.loader.Loader.executeQueryStatement(Loader.java:1875)
        at org.hibernate.loader.Loader.doQuery(Loader.java:919)
        at org.hibernate.loader.Loader.doQueryAndInitializeNonLazyCollections(Loader.java:336)
        at org.hibernate.loader.Loader.doList(Loader.java:2611)
        at org.hibernate.loader.Loader.doList(Loader.java:2594)
        at org.hibernate.loader.Loader.listIgnoreQueryCache(Loader.java:2423)
        at org.hibernate.loader.Loader.list(Loader.java:2418)
        at org.hibernate.loader.hql.QueryLoader.list(QueryLoader.java:501)
        at org.hibernate.hql.internal.ast.QueryTranslatorImpl.list(QueryTranslatorImpl.java:371)
        at org.hibernate.engine.query.spi.HQLQueryPlan.performList(HQLQueryPlan.java:216)
        at org.hibernate.internal.SessionImpl.list(SessionImpl.java:1326)
        at org.hibernate.internal.QueryImpl.list(QueryImpl.java:87)
        at org.hibernate.jpa.internal.QueryImpl.list(QueryImpl.java:606)
        at org.hibernate.jpa.internal.QueryImpl.getSingleResult(QueryImpl.java:529)
        at org.hibernate.jpa.criteria.compile.CriteriaQueryTypeQueryAdapter.getSingleResult(CriteriaQueryTypeQueryAdapter.java:54)
        at org.springframework.data.jpa.repository.query.JpaQueryExecution$SingleEntityExecution.doExecute(JpaQueryExecution.java:208)
        at org.springframework.data.jpa.repository.query.JpaQueryExecution.execute(JpaQueryExecution.java:87)
        at org.springframework.data.jpa.repository.query.AbstractJpaQuery.doExecute(AbstractJpaQuery.java:116)
        at org.springframework.data.jpa.repository.query.AbstractJpaQuery.execute(AbstractJpaQuery.java:106)
        at org.springframework.data.repository.core.support.RepositoryFactorySupport$QueryExecutorMethodInterceptor.doInvoke(RepositoryFactorySupport.java:499)
        at org.springframework.data.repository.core.support.RepositoryFactorySupport$QueryExecutorMethodInterceptor.invoke(RepositoryFactorySupport.java:477)
        at org.springframework.aop.framework.ReflectiveMethodInvocation.proceed(ReflectiveMethodInvocation.java:179)
        at org.springframework.data.projection.DefaultMethodInvokingMethodInterceptor.invoke(DefaultMethodInvokingMethodInterceptor.java:56)
        at org.springframework.aop.framework.ReflectiveMethodInvocation.proceed(ReflectiveMethodInvocation.java:179)
        at org.springframework.transaction.interceptor.TransactionInterceptor$1.proceedWithInvocation(TransactionInterceptor.java:99)
        at org.springframework.transaction.interceptor.TransactionAspectSupport.invokeWithinTransaction(TransactionAspectSupport.java:282)
        at org.springframework.transaction.interceptor.TransactionInterceptor.invoke(TransactionInterceptor.java:96)
        at org.springframework.aop.framework.ReflectiveMethodInvocation.proceed(ReflectiveMethodInvocation.java:179)
        at org.springframework.dao.support.PersistenceExceptionTranslationInterceptor.invoke(PersistenceExceptionTranslationInterceptor.java:136)
        at org.springframework.aop.framework.ReflectiveMethodInvocation.proceed(ReflectiveMethodInvocation.java:179)
        at org.springframework.data.jpa.repository.support.CrudMethodMetadataPostProcessor$CrudMethodMetadataPopulatingMethodInterceptor.invoke(CrudMethodMetadataPostProcessor.java:133)
        at org.springframework.aop.framework.ReflectiveMethodInvocation.proceed(ReflectiveMethodInvocation.java:179)
        at org.springframework.aop.interceptor.ExposeInvocationInterceptor.invoke(ExposeInvocationInterceptor.java:92)
        at org.springframework.aop.framework.ReflectiveMethodInvocation.proceed(ReflectiveMethodInvocation.java:179)
        at org.springframework.data.repository.core.support.SurroundingTransactionDetectorMethodInterceptor.invoke(SurroundingTransactionDetectorMethodInterceptor.java:57)
        at org.springframework.aop.framework.ReflectiveMethodInvocation.proceed(ReflectiveMethodInvocation.java:179)
        at org.springframework.aop.framework.JdkDynamicAopProxy.invoke(JdkDynamicAopProxy.java:213)
        at com.sun.proxy.$Proxy815.findByUsername(Unknown Source)
        at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
        at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:62)
        at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
        at java.lang.reflect.Method.invoke(Method.java:498)
        at org.springframework.aop.support.AopUtils.invokeJoinpointUsingReflection(AopUtils.java:333)
        at org.springframework.aop.framework.ReflectiveMethodInvocation.invokeJoinpoint(ReflectiveMethodInvocation.java:190)
        at org.springframework.aop.framework.ReflectiveMethodInvocation.proceed(ReflectiveMethodInvocation.java:157)
        at org.springframework.aop.framework.adapter.MethodBeforeAdviceInterceptor.invoke(MethodBeforeAdviceInterceptor.java:52)
        at org.springframework.aop.framework.ReflectiveMethodInvocation.proceed(ReflectiveMethodInvocation.java:179)
        at org.springframework.aop.aspectj.AspectJAfterAdvice.invoke(AspectJAfterAdvice.java:47)
        at org.springframework.aop.framework.ReflectiveMethodInvocation.proceed(ReflectiveMethodInvocation.java:179)
        at org.springframework.aop.interceptor.ExposeInvocationInterceptor.invoke(ExposeInvocationInterceptor.java:92)
        at org.springframework.aop.framework.ReflectiveMethodInvocation.proceed(ReflectiveMethodInvocation.java:179)
        at org.springframework.aop.framework.JdkDynamicAopProxy.invoke(JdkDynamicAopProxy.java:213)
        at com.sun.proxy.$Proxy815.findByUsername(Unknown Source)
        at it.integris.dataexploration.jwt.services.JwtUserDetailsServiceImpl.loadUserByUsername(JwtUserDetailsServiceImpl.java:26)
        at org.springframework.security.authentication.dao.DaoAuthenticationProvider.retrieveUser(DaoAuthenticationProvider.java:114)
        at org.springframework.security.authentication.dao.AbstractUserDetailsAuthenticationProvider.authenticate(AbstractUserDetailsAuthenticationProvider.java:144)
        at org.springframework.security.authentication.ProviderManager.authenticate(ProviderManager.java:174)
        at it.integris.dataexploration.jwt.controller.security.AuthenticationRestController.createAuthenticationToken(AuthenticationRestController.java:55)
        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.web.method.support.InvocableHandlerMethod.doInvoke(InvocableHandlerMethod.java:205)
        at org.springframework.web.method.support.InvocableHandlerMethod.invokeForRequest(InvocableHandlerMethod.java:133)
        at org.springframework.web.servlet.mvc.method.annotation.ServletInvocableHandlerMethod.invokeAndHandle(ServletInvocableHandlerMethod.java:97)
        at org.springframework.web.servlet.mvc.method.annotation.RequestMappingHandlerAdapter.invokeHandlerMethod(RequestMappingHandlerAdapter.java:827)
        at org.springframework.web.servlet.mvc.method.annotation.RequestMappingHandlerAdapter.handleInternal(RequestMappingHandlerAdapter.java:738)
        at org.springframework.web.servlet.mvc.method.AbstractHandlerMethodAdapter.handle(AbstractHandlerMethodAdapter.java:85)
        at org.springframework.web.servlet.DispatcherServlet.doDispatch(DispatcherServlet.java:967)
        at org.springframework.web.servlet.DispatcherServlet.doService(DispatcherServlet.java:901)
        at org.springframework.web.servlet.FrameworkServlet.processRequest(FrameworkServlet.java:970)
        at org.springframework.web.servlet.FrameworkServlet.doPost(FrameworkServlet.java:872)
        at javax.servlet.http.HttpServlet.service(HttpServlet.java:707)
        at org.springframework.web.servlet.FrameworkServlet.service(FrameworkServlet.java:846)
        at javax.servlet.http.HttpServlet.service(HttpServlet.java:790)
        at io.undertow.servlet.handlers.ServletHandler.handleRequest(ServletHandler.java:85)
        at io.undertow.servlet.handlers.FilterHandler$FilterChainImpl.doFilter(FilterHandler.java:129)
        at org.springframework.web.filter.OncePerRequestFilter.doFilter(OncePerRequestFilter.java:101)
        at io.undertow.servlet.core.ManagedFilter.doFilter(ManagedFilter.java:60)
        at io.undertow.servlet.handlers.FilterHandler$FilterChainImpl.doFilter(FilterHandler.java:131)
        at org.springframework.security.web.FilterChainProxy$VirtualFilterChain.doFilter(FilterChainProxy.java:317)
        at org.springframework.security.web.access.intercept.FilterSecurityInterceptor.invoke(FilterSecurityInterceptor.java:127)
        at org.springframework.security.web.access.intercept.FilterSecurityInterceptor.doFilter(FilterSecurityInterceptor.java:91)
        at org.springframework.security.web.FilterChainProxy$VirtualFilterChain.doFilter(FilterChainProxy.java:331)
        at org.springframework.security.web.access.ExceptionTranslationFilter.doFilter(ExceptionTranslationFilter.java:114)
        at org.springframework.security.web.FilterChainProxy$VirtualFilterChain.doFilter(FilterChainProxy.java:331)
        at org.springframework.security.web.session.SessionManagementFilter.doFilter(SessionManagementFilter.java:137)
        at org.springframework.security.web.FilterChainProxy$VirtualFilterChain.doFilter(FilterChainProxy.java:331)
        at org.springframework.security.web.authentication.AnonymousAuthenticationFilter.doFilter(AnonymousAuthenticationFilter.java:111)
        at org.springframework.security.web.FilterChainProxy$VirtualFilterChain.doFilter(FilterChainProxy.java:331)
        at org.springframework.security.web.servletapi.SecurityContextHolderAwareRequestFilter.doFilter(SecurityContextHolderAwareRequestFilter.java:170)
        at org.springframework.security.web.FilterChainProxy$VirtualFilterChain.doFilter(FilterChainProxy.java:331)
        at org.springframework.security.web.savedrequest.RequestCacheAwareFilter.doFilter(RequestCacheAwareFilter.java:63)
        at org.springframework.security.web.FilterChainProxy$VirtualFilterChain.doFilter(FilterChainProxy.java:331)
        at it.integris.dataexploration.jwt.security.JwtAuthenticationTokenFilter.doFilterInternal(JwtAuthenticationTokenFilter.java:66)
        at org.springframework.web.filter.OncePerRequestFilter.doFilter(OncePerRequestFilter.java:107)
        at org.springframework.security.web.FilterChainProxy$VirtualFilterChain.doFilter(FilterChainProxy.java:331)
        at org.springframework.security.web.authentication.logout.LogoutFilter.doFilter(LogoutFilter.java:116)
        at org.springframework.security.web.FilterChainProxy$VirtualFilterChain.doFilter(FilterChainProxy.java:331)
        at org.springframework.web.filter.CorsFilter.doFilterInternal(CorsFilter.java:96)
        at org.springframework.web.filter.OncePerRequestFilter.doFilter(OncePerRequestFilter.java:107)
        at org.springframework.security.web.FilterChainProxy$VirtualFilterChain.doFilter(FilterChainProxy.java:331)
        at org.springframework.security.web.header.HeaderWriterFilter.doFilterInternal(HeaderWriterFilter.java:64)
        at org.springframework.web.filter.OncePerRequestFilter.doFilter(OncePerRequestFilter.java:107)
        at org.springframework.security.web.FilterChainProxy$VirtualFilterChain.doFilter(FilterChainProxy.java:331)
        at org.springframework.security.web.context.SecurityContextPersistenceFilter.doFilter(SecurityContextPersistenceFilter.java:105)
        at org.springframework.security.web.FilterChainProxy$VirtualFilterChain.doFilter(FilterChainProxy.java:331)
        at org.springframework.security.web.context.request.async.WebAsyncManagerIntegrationFilter.doFilterInternal(WebAsyncManagerIntegrationFilter.java:56)
        at org.springframework.web.filter.OncePerRequestFilter.doFilter(OncePerRequestFilter.java:107)
        at org.springframework.security.web.FilterChainProxy$VirtualFilterChain.doFilter(FilterChainProxy.java:331)
        at org.springframework.security.web.FilterChainProxy.doFilterInternal(FilterChainProxy.java:214)
        at org.springframework.security.web.FilterChainProxy.doFilter(FilterChainProxy.java:177)
        at org.springframework.web.filter.DelegatingFilterProxy.invokeDelegate(DelegatingFilterProxy.java:347)
        at org.springframework.web.filter.DelegatingFilterProxy.doFilter(DelegatingFilterProxy.java:263)
        at io.undertow.servlet.core.ManagedFilter.doFilter(ManagedFilter.java:60)
        at io.undertow.servlet.handlers.FilterHandler$FilterChainImpl.doFilter(FilterHandler.java:131)
        at org.springframework.web.filter.RequestContextFilter.doFilterInternal(RequestContextFilter.java:99)
        at org.springframework.web.filter.OncePerRequestFilter.doFilter(OncePerRequestFilter.java:107)
        at io.undertow.servlet.core.ManagedFilter.doFilter(ManagedFilter.java:60)
        at io.undertow.servlet.handlers.FilterHandler$FilterChainImpl.doFilter(FilterHandler.java:131)
        at org.springframework.web.filter.HttpPutFormContentFilter.doFilterInternal(HttpPutFormContentFilter.java:108)
        at org.springframework.web.filter.OncePerRequestFilter.doFilter(OncePerRequestFilter.java:107)
        at io.undertow.servlet.core.ManagedFilter.doFilter(ManagedFilter.java:60)
        at io.undertow.servlet.handlers.FilterHandler$FilterChainImpl.doFilter(FilterHandler.java:131)
        at org.springframework.web.filter.HiddenHttpMethodFilter.doFilterInternal(HiddenHttpMethodFilter.java:81)
        at org.springframework.web.filter.OncePerRequestFilter.doFilter(OncePerRequestFilter.java:107)
        at io.undertow.servlet.core.ManagedFilter.doFilter(ManagedFilter.java:60)
        at io.undertow.servlet.handlers.FilterHandler$FilterChainImpl.doFilter(FilterHandler.java:131)
        at org.springframework.web.filter.CharacterEncodingFilter.doFilterInternal(CharacterEncodingFilter.java:197)
        at org.springframework.web.filter.OncePerRequestFilter.doFilter(OncePerRequestFilter.java:107)
        at io.undertow.servlet.core.ManagedFilter.doFilter(ManagedFilter.java:60)
        at io.undertow.servlet.handlers.FilterHandler$FilterChainImpl.doFilter(FilterHandler.java:131)
        at org.springframework.boot.web.support.ErrorPageFilter.doFilter(ErrorPageFilter.java:115)
        at org.springframework.boot.web.support.ErrorPageFilter.access$000(ErrorPageFilter.java:59)
        at org.springframework.boot.web.support.ErrorPageFilter$1.doFilterInternal(ErrorPageFilter.java:90)
        at org.springframework.web.filter.OncePerRequestFilter.doFilter(OncePerRequestFilter.java:107)
        at org.springframework.boot.web.support.ErrorPageFilter.doFilter(ErrorPageFilter.java:108)
        at io.undertow.servlet.core.ManagedFilter.doFilter(ManagedFilter.java:60)
        at io.undertow.servlet.handlers.FilterHandler$FilterChainImpl.doFilter(FilterHandler.java:131)
        at io.undertow.servlet.handlers.FilterHandler.handleRequest(FilterHandler.java:84)
        at io.undertow.servlet.handlers.security.ServletSecurityRoleHandler.handleRequest(ServletSecurityRoleHandler.java:62)
        at io.undertow.servlet.handlers.ServletDispatchingHandler.handleRequest(ServletDispatchingHandler.java:36)
        at org.wildfly.extension.undertow.security.SecurityContextAssociationHandler.handleRequest(SecurityContextAssociationHandler.java:78)
        at io.undertow.server.handlers.PredicateHandler.handleRequest(PredicateHandler.java:43)
        at io.undertow.servlet.handlers.security.SSLInformationAssociationHandler.handleRequest(SSLInformationAssociationHandler.java:131)
        at io.undertow.servlet.handlers.security.ServletAuthenticationCallHandler.handleRequest(ServletAuthenticationCallHandler.java:57)
        at io.undertow.server.handlers.PredicateHandler.handleRequest(PredicateHandler.java:43)
        at io.undertow.security.handlers.AbstractConfidentialityHandler.handleRequest(AbstractConfidentialityHandler.java:46)
        at io.undertow.servlet.handlers.security.ServletConfidentialityConstraintHandler.handleRequest(ServletConfidentialityConstraintHandler.java:64)
        at io.undertow.security.handlers.AuthenticationMechanismsHandler.handleRequest(AuthenticationMechanismsHandler.java:60)
        at io.undertow.servlet.handlers.security.CachedAuthenticatedSessionHandler.handleRequest(CachedAuthenticatedSessionHandler.java:77)
        at io.undertow.security.handlers.NotificationReceiverHandler.handleRequest(NotificationReceiverHandler.java:50)
        at io.undertow.security.handlers.AbstractSecurityContextAssociationHandler.handleRequest(AbstractSecurityContextAssociationHandler.java:43)
        at io.undertow.server.handlers.PredicateHandler.handleRequest(PredicateHandler.java:43)
        at org.wildfly.extension.undertow.security.jacc.JACCContextIdHandler.handleRequest(JACCContextIdHandler.java:61)
        at io.undertow.server.handlers.PredicateHandler.handleRequest(PredicateHandler.java:43)
        at io.undertow.server.handlers.PredicateHandler.handleRequest(PredicateHandler.java:43)
        at io.undertow.servlet.handlers.ServletInitialHandler.handleFirstRequest(ServletInitialHandler.java:284)
        at io.undertow.servlet.handlers.ServletInitialHandler.dispatchRequest(ServletInitialHandler.java:263)
        at io.undertow.servlet.handlers.ServletInitialHandler.access$000(ServletInitialHandler.java:81)
        at io.undertow.servlet.handlers.ServletInitialHandler$1.handleRequest(ServletInitialHandler.java:174)
        at io.undertow.server.Connectors.executeRootHandler(Connectors.java:202)
        at io.undertow.server.HttpServerExchange$1.run(HttpServerExchange.java:793)
        at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1142)
        at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:617)
        at java.lang.Thread.run(Thread.java:745)
Caused by: java.net.SocketException: Connection timed out
        at java.net.SocketInputStream.socketRead0(Native Method)
        at java.net.SocketInputStream.socketRead(SocketInputStream.java:116)
        at java.net.SocketInputStream.read(SocketInputStream.java:170)
        at java.net.SocketInputStream.read(SocketInputStream.java:141)
        at com.mysql.jdbc.util.ReadAheadInputStream.fill(ReadAheadInputStream.java:101)
        at com.mysql.jdbc.util.ReadAheadInputStream.readFromUnderlyingStreamIfNecessary(ReadAheadInputStream.java:144)
        at com.mysql.jdbc.util.ReadAheadInputStream.read(ReadAheadInputStream.java:174)
        at com.mysql.jdbc.MysqlIO.readFully(MysqlIO.java:3008)
        at com.mysql.jdbc.MysqlIO.reuseAndReadPacket(MysqlIO.java:3469)

My application is deployed on a wildFly 10.0.0 application server, otherwise I'm using tomcat-jdbc 8.5.23 like connection pool. Anyway this is my pom.xml dependencies:

<dependencies>
    <dependency>
        <groupId>org.springframework.boot</groupId>
        <artifactId>spring-boot-starter-web</artifactId>
        <exclusions>
            <exclusion>
                <groupId>org.apache.tomcat.embed</groupId>
                <artifactId>tomcat-embed-websocket</artifactId>
            </exclusion>
        </exclusions>
    </dependency>

    <dependency>
        <groupId>org.springframework.boot</groupId>
        <artifactId>spring-boot-starter-test</artifactId>
        <scope>test</scope>
    </dependency>

    <dependency>
        <groupId>io.jsonwebtoken</groupId>
        <artifactId>jjwt</artifactId>
        <version>0.9.0</version>
    </dependency>


    <dependency>
        <groupId>org.springframework.boot</groupId>
        <artifactId>spring-boot-starter-data-jpa</artifactId>
        <exclusions>
            <exclusion>
                <artifactId>hibernate-entitymanager</artifactId>
                <groupId>org.hibernate</groupId>
            </exclusion>
            <exclusion>
                <artifactId>hibernate-core</artifactId>
                <groupId>org.hibernate</groupId>
            </exclusion>
        </exclusions>
    </dependency>

    <dependency>

I read more article about this problem: Debugging Communication Link Failure exceptions in Connector/J

Any suggestion about this problem? Can i add some properties in my application.properties to validate idle connection or the problem could be solved changed poll connection?

Edit1 I'm trying to add the following properties in my application.properties:

spring.datasource.testOnBorrow=true
spring.datasource.validationQuery=SELECT 1
spring.datasource.testWhileIdle = true
spring.datasource.timeBetweenEvictionRunsMillis = 60000

but the problem perstist. Now from your answer seems that i have to change the names in the application.properties:

spring.datasource.tomcat.validation-query: SELECT 1
spring.datasource.tomcat.test-on-borrow: true
spring.datasource.tomcat.validation-interval: 30000

Edit2

My connect_timeout = 10

My connection pool after show process list is:

How can I understand if the properties added do their duty?

Answer 1

I solved my problem changing connection pool. Spring boot 1.5.9 uses tomcat-jdbc like connection pool, in my case seems that this pool had same trouble about connection relasing, than i replaced tomcat connection pool with HikariCP.

Changes to pom.xml:

//Added HikariCP 
<dependency>
  <groupId>com.zaxxer</groupId>
  <artifactId>HikariCP</artifactId>
</dependency>

//Excluded Tomcat-jbc
<dependency>
    <groupId>org.springframework.boot</groupId>
    <artifactId>spring-boot-starter-data-jpa</artifactId>
    <exclusions>
        <exclusion>
            <artifactId>tomcat-jdbc</artifactId>
            <groupId>org.apache.tomcat</groupId>
        </exclusion>
    </exclusions>
</dependency>

Changes to application.properties:

//Added some properties to application.properties

spring.datasource.hikari.connection-test-query: SELECT 1 FROM DUAL
spring.datasource.hikari.minimum-idle: 1
spring.datasource.hikari.maximum-pool-size: 5
spring.datasource.hikari.pool-name: havasPoolName
spring.datasource.hikari.auto-commit: false
spring.datasource.hikari.type: com.zaxxer.hikari.HikariDataSource

Answer 2

Can i add some properties in my application.properties to validate idle connection or the problem could be solved changed poll connection

Yes you should do that.

Normally, spring will init tomcat pool and setup validation correctly. If somehow you broke the autowire part, or create custom pool then you may missing the setting.

The problem occur when a connection from pool is borrowed, but that connection already timeout so the connection failed.

This is my setting to ensure the pool validate connections:

spring:
  datasource:
    tomcat:
      validation-query: SELECT 1
      test-on-borrow: true
      validation-interval: 30000 # 30s