我有Spring应用程序，该应用程序在我的本地计算机上运行在Tomcat(7.0.68(上使用Google Cloud MySQL实例。我也使用C3P0(0.9.1.2(作为连接池。您可以在下面找到DAOcontext.xml文件和CATALINA_OPTS的一部分：
....
<bean id="dataSource" class="com.mchange.v2.c3p0.ComboPooledDataSource">
<property name="driverClass" value="com.mysql.jdbc.Driver"/>
<property name="jdbcUrl" value="jdbc:mysql://sql_instance_ip:3306/table_name?verifyServerCertificate=true&useSSL=true&requireSSL=true&trustCertificateKeyStoreUrl=file:/path/to/trustStore.jks&trustCertificateKeyStorePassword=****&characterEncoding=UTF-8&useUnicode=true&autoReconnect=true&useServerPrepStmts=false&rewriteBatchedStatements=true&failOverReadOnly=false&zeroDateTimeBehavior=convertToNull"/>
<property name="user" value="***"/>
<property name="password" value="****"/>
<property name="acquireIncrement" value="1"/>
<property name="initialPoolSize" value="1"/>
<property name="minPoolSize" value="1"/>
<property name="maxPoolSize" value="5"/>
<property name="maxIdleTime" value="120"/>
</bean>
...
CATALINA_OPTS="... -Djavax.net.ssl.keyStore=/path/to/keyStore.jks -Djavax.net.ssl.keyStorePassword=**** ..."
仅供参考，这些密钥存储是从我的 SQL 实例的证书创建的，并且我的本地 IP 已列入此 MySQL 实例的白名单。 https://cloud.google.com/sql/docs/mysql/configure-ssl-instance
当我从仪表板禁用"仅允许 SSL 连接">选项时，我的应用程序运行没有任何数据库连接问题。此外，当我通过WireShark检查我的应用程序和SQL实例之间的连接时，我看到数据包是SSL加密的。
当我启用此选项时，我的 tomcat 应用程序会给出以下错误：
May 07, 2018 5:02:49 PM com.mchange.v2.c3p0.impl.AbstractPoolBackedDataSource getPoolManager
INFO: Initializing c3p0 pool... com.mchange.v2.c3p0.ComboPooledDataSource [ acquireIncrement -> 1, acquireRetryAttempts -> 30, acquireRetryDelay -> 1000, autoCommitOnClose -> false, automaticTestTable -> null, breakAfterAcquireFailure -> false, checkoutTimeout -> 0, connectionCustomizerClassName -> null, connectionTesterClassName -> com.mchange.v2.c3p0.impl.DefaultConnectionTester, dataSourceName -> z8kfsx9u1h2ypospw6bfm|37fcf007, debugUnreturnedConnectionStackTraces -> false, description -> null, driverClass -> com.mysql.jdbc.Driver, factoryClassLocation -> null, forceIgnoreUnresolvedTransactions -> false, identityToken -> z8kfsx9u1h2ypospw6bfm|37fcf007, idleConnectionTestPeriod -> 0, initialPoolSize -> 1, jdbcUrl -> jdbc:mysql://sql_instance_ip:3306/table_name?verifyServerCertificate=true&useSSL=true&requireSSL=true&trustCertificateKeyStoreUrl=file:/path/to/trustStore.jks&trustCertificateKeyStorePassword=****&characterEncoding=UTF-8&useUnicode=true&autoReconnect=true&useServerPrepStmts=false&rewriteBatchedStatements=true&failOverReadOnly=false&zeroDateTimeBehavior=convertToNull"/, maxAdministrativeTaskTime -> 0, maxConnectionAge -> 0, maxIdleTime -> 120, maxIdleTimeExcessConnections -> 0, maxPoolSize -> 5, maxStatements -> 0, maxStatementsPerConnection -> 0, minPoolSize -> 1, numHelperThreads -> 3, numThreadsAwaitingCheckoutDefaultUser -> 0, preferredTestQuery -> null, properties -> {user=******, password=******}, propertyCycle -> 0, testConnectionOnCheckin -> false, testConnectionOnCheckout -> false, unreturnedConnectionTimeout -> 0, usesTraditionalReflectiveProxies -> false ]
May 07, 2018 5:03:09 PM com.mchange.v2.async.ThreadPoolAsynchronousRunner$DeadlockDetector run
WARNING: com.mchange.v2.async.ThreadPoolAsynchronousRunner$DeadlockDetector@274517d0 -- APPARENT DEADLOCK!!! Creating emergency threads for unassigned pending tasks!
May 07, 2018 5:03:09 PM com.mchange.v2.async.ThreadPoolAsynchronousRunner$DeadlockDetector run
WARNING: com.mchange.v2.async.ThreadPoolAsynchronousRunner$DeadlockDetector@274517d0 -- APPARENT DEADLOCK!!! Complete Status:
Managed Threads: 3
Active Threads: 3
Active Tasks:
com.mchange.v2.resourcepool.BasicResourcePool$AcquireTask@68bff773 (com.mchange.v2.async.ThreadPoolAsynchronousRunner$PoolThread-#1)
com.mchange.v2.resourcepool.BasicResourcePool$AcquireTask@67cb9623 (com.mchange.v2.async.ThreadPoolAsynchronousRunner$PoolThread-#2)
com.mchange.v2.resourcepool.BasicResourcePool$AcquireTask@599d5f2f (com.mchange.v2.async.ThreadPoolAsynchronousRunner$PoolThread-#0)
Pending Tasks:
com.mchange.v2.resourcepool.BasicResourcePool$AcquireTask@1f0360c0
com.mchange.v2.resourcepool.BasicResourcePool$AcquireTask@890083c
Pool thread stack traces:
Thread[com.mchange.v2.async.ThreadPoolAsynchronousRunner$PoolThread-#1,5,main]
java.lang.Thread.sleep(Native Method)
com.mysql.jdbc.ConnectionImpl.connectWithRetries(ConnectionImpl.java:2376)
com.mysql.jdbc.ConnectionImpl.createNewIO(ConnectionImpl.java:2306)
com.mysql.jdbc.ConnectionImpl.<init>(ConnectionImpl.java:834)
com.mysql.jdbc.JDBC4Connection.<init>(JDBC4Connection.java:47)
sun.reflect.NativeConstructorAccessorImpl.newInstance0(Native Method)
....
这些错误日志并非特定于此问题，但它们类似于我的应用程序无法连接数据库时得到的错误日志。你对这个问题有什么想法或建议吗？是否有人使用类似的设置并遇到此问题？
任何帮助和建议都非常感谢！
这似乎是一个配置问题。我建议您再次按照官方文档中描述的所有步骤进行操作，并检查您的服务器证书是否仍然有效。
作为一种解决方法，我建议使用Cloud SQL代理的可能性。