com.mysql.jdbc.exceptions.jdbc4.CommunicationsException MySQL + Apache Tomcat 7

Question

我的應用程序（Spring 4 MVC/Hibernate 4/MySQL/Maven）使用基於註釋的配置集成了Spring和Hibernate。之後的這幾個小時不使用的數據庫中，我總是看到這樣的錯誤：

com.mysql.jdbc.exceptions.jdbc4.CommunicationsException: The last packet successfully received from the server was 84,510,841 milliseconds ago. The last packet sent successfully to the server was 84,510,841 milliseconds ago. is longer than the server configured value of 'wait_timeout'. You should consider either expiring and/or testing connection validity before use in your application, increasing the server configured values for client timeouts, or using the Connector/J connection property 'autoReconnect=true' to avoid this problem. 
    sun.reflect.NativeConstructorAccessorImpl.newInstance0(Native Method) 
    sun.reflect.NativeConstructorAccessorImpl.newInstance(NativeConstructorAccessorImpl.java:57) 
    sun.reflect.DelegatingConstructorAccessorImpl.newInstance(DelegatingConstructorAccessorImpl.java:45) 
    java.lang.reflect.Constructor.newInstance(Constructor.java:526) 
    com.mysql.jdbc.Util.handleNewInstance(Util.java:411) 
    com.mysql.jdbc.SQLError.createCommunicationsException(SQLError.java:1121) 
    com.mysql.jdbc.MysqlIO.send(MysqlIO.java:3938) 
    com.mysql.jdbc.MysqlIO.sendCommand(MysqlIO.java:2551) 
    com.mysql.jdbc.MysqlIO.sqlQueryDirect(MysqlIO.java:2731) 
    com.mysql.jdbc.ConnectionImpl.execSQL(ConnectionImpl.java:2809) 
    com.mysql.jdbc.ConnectionImpl.setAutoCommit(ConnectionImpl.java:5333) 
    sun.reflect.GeneratedMethodAccessor58.invoke(Unknown Source) 
    sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43) 
    java.lang.reflect.Method.invoke(Method.java:606) 
    org.apache.tomcat.jdbc.pool.ProxyConnection.invoke(ProxyConnection.java:126) 
    org.apache.tomcat.jdbc.pool.JdbcInterceptor.invoke(JdbcInterceptor.java:109) 
    org.apache.tomcat.jdbc.pool.DisposableConnectionFacade.invoke(DisposableConnectionFacade.java:80) 
    com.sun.proxy.$Proxy33.setAutoCommit(Unknown Source) 
    org.hibernate.resource.jdbc.internal.AbstractLogicalConnectionImplementor.begin(AbstractLogicalConnectionImplementor.java:67) 
    org.hibernate.resource.jdbc.internal.LogicalConnectionManagedImpl.begin(LogicalConnectionManagedImpl.java:238) 
    org.hibernate.resource.transaction.backend.jdbc.internal.JdbcResourceLocalTransactionCoordinatorImpl$TransactionDriverControlImpl.begin(JdbcResourceLocalTransactionCoordinatorImpl.java:213) 
    org.hibernate.engine.transaction.internal.TransactionImpl.begin(TransactionImpl.java:52) 
    org.hibernate.internal.SessionImpl.beginTransaction(SessionImpl.java:1512) 
    org.hibernate.jpa.internal.TransactionImpl.begin(TransactionImpl.java:45) 
    org.springframework.orm.jpa.vendor.HibernateJpaDialect.beginTransaction(HibernateJpaDialect.java:170) 
    org.springframework.orm.jpa.JpaTransactionManager.doBegin(JpaTransactionManager.java:380) 
    org.springframework.transaction.support.AbstractPlatformTransactionManager.getTransaction(AbstractPlatformTransactionManager.java:373) 
    org.springframework.transaction.interceptor.TransactionAspectSupport.createTransactionIfNecessary(TransactionAspectSupport.java:427) 
    org.springframework.transaction.interceptor.TransactionAspectSupport.invokeWithinTransaction(TransactionAspectSupport.java:276) 
    org.springframework.transaction.interceptor.TransactionInterceptor.invoke(TransactionInterceptor.java:96) 
    org.springframework.aop.framework.ReflectiveMethodInvocation.proceed(ReflectiveMethodInvocation.java:179) 
    org.springframework.aop.framework.JdkDynamicAopProxy.invoke(JdkDynamicAopProxy.java:208) 
    com.sun.proxy.$Proxy118.findAll(Unknown Source) 
    com.ideefe.iot.controller.AppController.listDevices(AppController.java:49) 
    sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method) 
    sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:57) 
    sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43) 
    java.lang.reflect.Method.invoke(Method.java:606) 
    org.springframework.web.method.support.InvocableHandlerMethod.doInvoke(InvocableHandlerMethod.java:222) 
    org.springframework.web.method.support.InvocableHandlerMethod.invokeForRequest(InvocableHandlerMethod.java:137) 
    org.springframework.web.servlet.mvc.method.annotation.ServletInvocableHandlerMethod.invokeAndHandle(ServletInvocableHandlerMethod.java:110) 
    org.springframework.web.servlet.mvc.method.annotation.RequestMappingHandlerAdapter.invokeHandlerMethod(RequestMappingHandlerAdapter.java:814) 
    org.springframework.web.servlet.mvc.method.annotation.RequestMappingHandlerAdapter.handleInternal(RequestMappingHandlerAdapter.java:737) 
    org.springframework.web.servlet.mvc.method.AbstractHandlerMethodAdapter.handle(AbstractHandlerMethodAdapter.java:85) 
    org.springframework.web.servlet.DispatcherServlet.doDispatch(DispatcherServlet.java:959) 
    org.springframework.web.servlet.DispatcherServlet.doService(DispatcherServlet.java:893) 
    org.springframework.web.servlet.FrameworkServlet.processRequest(FrameworkServlet.java:970) 
    org.springframework.web.servlet.FrameworkServlet.doGet(FrameworkServlet.java:861) 
    javax.servlet.http.HttpServlet.service(HttpServlet.java:620) 
    org.springframework.web.servlet.FrameworkServlet.service(FrameworkServlet.java:846) 
    javax.servlet.http.HttpServlet.service(HttpServlet.java:727) 
    org.springframework.web.filter.CharacterEncodingFilter.doFilterInternal(CharacterEncodingFilter.java:121) 
    org.springframework.web.filter.OncePerRequestFilter.doFilter(OncePerRequestFilter.java:107) 
    org.springframework.web.filter.HiddenHttpMethodFilter.doFilterInternal(HiddenHttpMethodFilter.java:77) 
    org.springframework.web.filter.OncePerRequestFilter.doFilter(OncePerRequestFilter.java:107) 
    org.springframework.web.multipart.support.MultipartFilter.doFilterInternal(MultipartFilter.java:118) 
    org.springframework.web.filter.OncePerRequestFilter.doFilter(OncePerRequestFilter.java:107) 

下面是MySQL數據庫my.cnf文件：

devuser@localhost:/etc/apache2$ more /etc/mysql/my.cnf 
# 
# The MySQL database server configuration file. 
# 
# You can copy this to one of: 
# - "/etc/mysql/my.cnf" to set global options, 
# - "~/.my.cnf" to set user-specific options. 
# 
# One can use all long options that the program supports. 
# Run program with --help to get a list of available options and with 
# --print-defaults to see which it would actually understand and use. 
# 
# For explanations see 
# http://dev.mysql.com/doc/mysql/en/server-system-variables.html 

# This will be passed to all mysql clients 
# It has been reported that passwords should be enclosed with ticks/quotes 
# escpecially if they contain "#" chars... 
# Remember to edit /etc/mysql/debian.cnf when changing the socket location. 
[client] 
port  = 3306 
socket  = /var/run/mysqld/mysqld.sock 

# Here is entries for some specific programs 
# The following values assume you have at least 32M ram 

# This was formally known as [safe_mysqld]. Both versions are currently parsed. 
[mysqld_safe] 
socket  = /var/run/mysqld/mysqld.sock 
nice  = 0 

[mysqld] 
# 
# * Basic Settings 
# 
user  = mysql 
pid-file = /var/run/mysqld/mysqld.pid 
socket  = /var/run/mysqld/mysqld.sock 
port  = 3306 
basedir  = /usr 
datadir  = /var/lib/mysql 
tmpdir  = /tmp 
lc-messages-dir = /usr/share/mysql 
skip-external-locking 
# 
# Instead of skip-networking the default is now to listen only on 
# localhost which is more compatible and is not less secure. 
bind-address  = 127.0.0.1 
# 
# * Fine Tuning 
# 
key_buffer  = 32M 
max_allowed_packet = 1M 
thread_stack  = 128K 
thread_cache_size  = 8 
# This replaces the startup script and checks MyISAM tables if needed 
# the first time they are touched 
myisam-recover   = BACKUP 
max_connections  = 75 
table_cache   = 32 
#thread_concurrency  = 10 
# 
# * Query Cache Configuration 
# 
query_cache_limit = 1M 
query_cache_size  = 16M 
# 
# * Logging and Replication 
# 
# Both location gets rotated by the cronjob. 
# Be aware that this log type is a performance killer. 
# As of 5.1 you can enable the log at runtime! 
#general_log_file  = /var/log/mysql/mysql.log 
#general_log    = 1 
# 
# Error log - should be very few entries. 
# 
log_error = /var/log/mysql/error.log 
# 
# Here you can see queries with especially long duration 
#log_slow_queries = /var/log/mysql/mysql-slow.log 
#long_query_time = 2 
#log-queries-not-using-indexes 
# 
# The following can be used as easy to replay backup logs or for replication. 
# note: if you are setting up a replication slave, see README.Debian about 
#  other settings you may need to change. 
#server-id  = 1 
#log_bin   = /var/log/mysql/mysql-bin.log 
expire_logs_days = 10 
max_binlog_size   = 100M 
#binlog_do_db  = include_database_name 
#binlog_ignore_db = include_database_name 
# 
# * InnoDB 
# 
# InnoDB is enabled by default with a 10MB datafile in /var/lib/mysql/. 
# Read the manual for more InnoDB related options. There are many! 
# 
# * Security Features 
# 
# Read the manual, too, if you want chroot! 
# chroot = /var/lib/mysql/ 
# 
# For generating SSL certificates I recommend the OpenSSL GUI "tinyca". 
# 
# ssl-ca=/etc/mysql/cacert.pem 
# ssl-cert=/etc/mysql/server-cert.pem 
# ssl-key=/etc/mysql/server-key.pem 



[mysqldump] 
quick 
quote-names 
max_allowed_packet = 16M 

[mysql] 
#no-auto-rehash # faster start of mysql but no tab completition 

[isamchk] 
key_buffer  = 16M 

# 
# * IMPORTANT: Additional settings that can override those from this file! 
# The files must end with '.cnf', otherwise they'll be ignored. 
# 
!includedir /etc/mysql/conf.d/ 

我使用的定義爲連接池如下：

<?xml version="1.0" encoding="UTF-8"?> 
<Context> 
    <!-- Especifica un DataSource JDBC. --> 
    <Resource name="jdbc/devicesDS" 
       auth="Container" 
       type="javax.sql.DataSource" 
       maxActive="10" 
       maxIdle="4" 
       username="root" 
       password="SrbBfsatn640^" 
       driverClassName="com.mysql.jdbc.Driver" 
       url="jdbc:mysql://localhost:3306/devices?autoReconnect=true" 
       validationQuery="select 1 from dual" /> 
</Context> 

Answer 1

看起來像這是MySQL inactivity timeout - 圍繞它有相當多的類似StackOverflow問題（例如here,here和here）。奉勸加入testOnBorrow=true，即改變你的連接池設置：

<Resource name="jdbc/devicesDS" 
      auth="Container" 
      type="javax.sql.DataSource" 
      maxActive="10" 
      maxIdle="4" 
      username="root" 
      password="SrbBfsatn640^" 
      driverClassName="com.mysql.jdbc.Driver" 
      url="jdbc:mysql://localhost:3306/devices?autoReconnect=true" 
      validationQuery="select 1 from dual" 
      testOnBorrow=true /> 

會親自的偏向testOnBorrow超過testWhileIdle的選擇，因爲前者是完全獨立於wait_timeout價值 - 但不知道如何表現進行比較。對於在錯誤文本中建議的JDBC URL中使用autoreconnect=true替代方案，請親自謹慎 - 請參閱comment here，原因爲何。

Answer 2

在您的應用程序的連接字符串mysql數據庫應該是：

jdbc:mysql://{host}:{port}/{schema}?autoReconnect=true 

加入autoReconnect的= true，將會解決這個問題

Answer 3

我運行到這個問題與其他應用程序實現，tryed每個配置後，autoreconnect等 我發現解決這個問題的唯一方法是製作一個調度事件，每小時調用一次測試查詢來ping數據庫，強制它刷新連接。

query("SELECT version()");