db2 驱动错误但能够建立连接

Question

我正在尝试将C3P0 连接池用于 IBM DB2 Version 10.5.5 Fix Pack 5 和 Java 8。

最初，我收到了this error，所以我将 jar 更改为db2jcc4.jar，但我仍然在控制台中遇到以下错误，

1350 [C3P0PooledConnectionPoolManager[identityToken->2x0fal9iui9mpmdj6im3|c2e1f26]-HelperThread-#1] INFO  com.mchange.v2.c3p0.SQLWarnings  – Origination unknown: [10228][11541][4.11.77] Security exceptions occurred while loading driver. ERRORCODE=4223, SQLSTATE=null
com.ibm.db2.jcc.am.SqlWarning: Origination unknown: [10228][11541][4.11.77] Security exceptions occurred while loading driver. ERRORCODE=4223, SQLSTATE=null
    at com.ibm.db2.jcc.am.gd.b(gd.java:207)
    at com.ibm.db2.jcc.am.gd.b(gd.java:258)
    at com.ibm.db2.jcc.am.jb.a(jb.java:887)
    at com.ibm.db2.jcc.am.lb.a(lb.java:574)
    at com.ibm.db2.jcc.am.lb.<init>(lb.java:555)
    at com.ibm.db2.jcc.t4.b.<init>(b.java:305)
    at com.ibm.db2.jcc.DB2SimpleDataSource.getConnection(DB2SimpleDataSource.java:214)
    at com.ibm.db2.jcc.DB2Driver.connect(DB2Driver.java:460)
    at com.mchange.v2.c3p0.DriverManagerDataSource.getConnection(DriverManagerDataSource.java:175)
    at com.mchange.v2.c3p0.WrapperConnectionPoolDataSource.getPooledConnection(WrapperConnectionPoolDataSource.java:220)
    at com.mchange.v2.c3p0.WrapperConnectionPoolDataSource.getPooledConnection(WrapperConnectionPoolDataSource.java:206)
    at com.mchange.v2.c3p0.impl.C3P0PooledConnectionPool$1PooledConnectionResourcePoolManager.acquireResource(C3P0PooledConnectionPool.java:203)
    at com.mchange.v2.resourcepool.BasicResourcePool.doAcquire(BasicResourcePool.java:1138)
    at com.mchange.v2.resourcepool.BasicResourcePool.doAcquireAndDecrementPendingAcquiresWithinLockOnSuccess(BasicResourcePool.java:1125)
    at com.mchange.v2.resourcepool.BasicResourcePool.access$700(BasicResourcePool.java:44)
    at com.mchange.v2.resourcepool.BasicResourcePool$ScatteredAcquireTask.run(BasicResourcePool.java:1870)
    at com.mchange.v2.async.ThreadPoolAsynchronousRunner$PoolThread.run(ThreadPoolAsynchronousRunner.java:696)
Caused by: java.security.PrivilegedActionException: java.lang.ClassNotFoundException: sun.io.ByteToCharConverter
    at java.security.AccessController.doPrivileged(Native Method)
    at com.ibm.db2.jcc.am.jb.r(jb.java:873)
    at com.ibm.db2.jcc.am.jb.<clinit>(jb.java:484)
    at com.ibm.db2.jcc.DB2Driver.connect(DB2Driver.java:117)
    ... 9 more
Caused by: java.lang.ClassNotFoundException: sun.io.ByteToCharConverter
    at java.net.URLClassLoader.findClass(Unknown Source)
    at java.lang.ClassLoader.loadClass(Unknown Source)
    at sun.misc.Launcher$AppClassLoader.loadClass(Unknown Source)
    at java.lang.ClassLoader.loadClass(Unknown Source)
    at java.lang.Class.forName0(Native Method)
    at java.lang.Class.forName(Unknown Source)
    at com.ibm.db2.jcc.am.jg.run(jg.java:19)
    ... 13 more
1350 [C3P0PooledConnectionPoolManager[identityToken->2x0fal9iui9mpmdj6im3|c2e1f26]-HelperThread-#0] INFO  com.mchange.v2.c3p0.SQLWarnings  – Origination unknown: [10228][11541][4.11.77] Security exceptions occurred while loading driver. ERRORCODE=4223, SQLSTATE=null
com.ibm.db2.jcc.am.SqlWarning: Origination unknown: [10228][11541][4.11.77] Security exceptions occurred while loading driver. ERRORCODE=4223, SQLSTATE=null
    at com.ibm.db2.jcc.am.gd.b(gd.java:207)
    at com.ibm.db2.jcc.am.gd.b(gd.java:258)
    at com.ibm.db2.jcc.am.jb.a(jb.java:887)
    at com.ibm.db2.jcc.am.lb.a(lb.java:574)
    at com.ibm.db2.jcc.am.lb.<init>(lb.java:555)
    at com.ibm.db2.jcc.t4.b.<init>(b.java:305)
    at com.ibm.db2.jcc.DB2SimpleDataSource.getConnection(DB2SimpleDataSource.java:214)
    at com.ibm.db2.jcc.DB2Driver.connect(DB2Driver.java:460)
    at com.mchange.v2.c3p0.DriverManagerDataSource.getConnection(DriverManagerDataSource.java:175)
    at com.mchange.v2.c3p0.WrapperConnectionPoolDataSource.getPooledConnection(WrapperConnectionPoolDataSource.java:220)
    at com.mchange.v2.c3p0.WrapperConnectionPoolDataSource.getPooledConnection(WrapperConnectionPoolDataSource.java:206)
    at com.mchange.v2.c3p0.impl.C3P0PooledConnectionPool$1PooledConnectionResourcePoolManager.acquireResource(C3P0PooledConnectionPool.java:203)
    at com.mchange.v2.resourcepool.BasicResourcePool.doAcquire(BasicResourcePool.java:1138)
    at com.mchange.v2.resourcepool.BasicResourcePool.doAcquireAndDecrementPendingAcquiresWithinLockOnSuccess(BasicResourcePool.java:1125)
    at com.mchange.v2.resourcepool.BasicResourcePool.access$700(BasicResourcePool.java:44)
    at com.mchange.v2.resourcepool.BasicResourcePool$ScatteredAcquireTask.run(BasicResourcePool.java:1870)
    at com.mchange.v2.async.ThreadPoolAsynchronousRunner$PoolThread.run(ThreadPoolAsynchronousRunner.java:696)
Caused by: java.security.PrivilegedActionException: java.lang.ClassNotFoundException: sun.io.ByteToCharConverter
    at java.security.AccessController.doPrivileged(Native Method)
    at com.ibm.db2.jcc.am.jb.r(jb.java:873)
    at com.ibm.db2.jcc.am.jb.<clinit>(jb.java:484)
    at com.ibm.db2.jcc.DB2Driver.connect(DB2Driver.java:117)
    ... 9 more
Caused by: java.lang.ClassNotFoundException: sun.io.ByteToCharConverter
    at java.net.URLClassLoader.findClass(Unknown Source)
    at java.lang.ClassLoader.loadClass(Unknown Source)
    at sun.misc.Launcher$AppClassLoader.loadClass(Unknown Source)
    at java.lang.ClassLoader.loadClass(Unknown Source)
    at java.lang.Class.forName0(Native Method)
    at java.lang.Class.forName(Unknown Source)
    at com.ibm.db2.jcc.am.jg.run(jg.java:19)
    ... 13 more

即使日志中出现此错误，我的独立 Java 应用程序也能够连接到数据库并获得结果，即 SELECT 查询已成功执行。

如何解决这种混乱？

Answer 1

您看到的堆栈跟踪来自 SqlWarning 对象，这可能意味着它们不是致命或严重的问题。明显的问题java.lang.ClassNotFoundException: sun.io.ByteToCharConverter 似乎很奇怪。但是由于它是作为警告而不是作为异常抛出的，驱动程序可能已经从问题中恢复过来，这就是您的应用程序似乎可以工作的原因。

JDBC 连接被允许存储a chain of SQLWarnings，它可能来自任何东西，但大多数应用程序会忽略它。 （大多数 JDBC 程序员甚至都不知道它们的存在。）

c3p0 对于定期检查连接警告、记录它们然后清除它们非常神经质，这样连接的用户就不会看到来自先前客户端使用的警告。但是，警告的日志记录可能很烦人，因此，如果您愿意，可以很容易地抑制它（或将其重定向到单独的文件，或其他）。 c3p0 将警告记录到名为com.mchange.v2.c3p0.SQLWarnings 的特殊记录器中。在您使用的任何日志记录库的配置文件中，您可以通过将该记录器的级别设置为 WARNING 或更高来抑制此输出。

（有点令人困惑的是，SQLWarnings 记录在INFO 而不是WARNING。由于它们通常代表有关已恢复条件的信息，驱动程序作者知道大多数开发人员从未见过，因此它们实际上并没有上升到WARNING。因此，在INFO 及以下过滤掉来自com.mchange.v2.c3p0.SQLWarnings 的消息足以消除警告。如果您想查看负责的代码，它是here。）