在更改完用户的权限后，必须使用刷新权限吗，我在更新完用户权限后，没有刷新权限，但是也更改成功了

这个第一个题目不是说不包括Zlotkey吗，答案怎么包含

这题不对哦，应该怎么查询小写a呢，课堂老师的查询包含了大写A

老师，这个警告怎么处理呢？网上说在url后添加?useSSL=false 。怎么在同时指定编码

?useUnicode=true&characterEncoding=utf-8

的情况下添加这个?useSSL=false呢？

老师，能不能把整章的数据库文件发上来呢

为什么我的局部变量list不能在try块中正常使用

老师好，建议显示 提问和回答时间，希望老师们给出回应

问题：老师我用c3p0数据库连接池用配置文件实现连接时报错了，你看是我这个xml文件建的有问题吗，还是c3p0-0.9.1.2.jar这个版本还需要依赖别的jar包，下面是报的错，最下面是配置文件图片

六月 19, 2020 10:37:26 上午 com.mchange.v2.log.MLog <clinit>

信息: MLog clients using java 1.4+ standard logging.

六月 19, 2020 10:37:27 上午 com.mchange.v2.c3p0.C3P0Registry banner

信息: Initializing c3p0-0.9.1.2 [built 21-May-2007 15:04:56; debug? true; trace: 10]

六月 19, 2020 10:37:27 上午 com.mchange.v2.c3p0.impl.AbstractPoolBackedDataSource getPoolManager

信息: Initializing c3p0 pool... com.mchange.v2.c3p0.ComboPooledDataSource [ acquireIncrement -> 5, acquireRetryAttempts -> 30, acquireRetryDelay -> 1000, autoCommitOnClose -> false, automaticTestTable -> null, breakAfterAcquireFailure -> false, checkoutTimeout -> 0, connectionCustomizerClassName -> null, connectionTesterClassName -> com.mchange.v2.c3p0.impl.DefaultConnectionTester, dataSourceName -> hellc3p0, debugUnreturnedConnectionStackTraces -> false, description -> null, driverClass -> com.mysql.jdbc.Driver, factoryClassLocation -> null, forceIgnoreUnresolvedTransactions -> false, identityToken -> 1hge9eiaa1k63i3np8f2kz|e73f9ac, idleConnectionTestPeriod -> 0, initialPoolSize -> 10, jdbcUrl -> jdbc.mysql://localhost:3306/test, maxAdministrativeTaskTime -> 0, maxConnectionAge -> 0, maxIdleTime -> 0, maxIdleTimeExcessConnections -> 0, maxPoolSize -> 100, maxStatements -> 0, maxStatementsPerConnection -> 2, minPoolSize -> 10, numHelperThreads -> 3, numThreadsAwaitingCheckoutDefaultUser -> 0, preferredTestQuery -> null, properties -> {user=******, password=******}, propertyCycle -> 0, testConnectionOnCheckin -> false, testConnectionOnCheckout -> false, unreturnedConnectionTimeout -> 0, usesTraditionalReflectiveProxies -> false ]

六月 19, 2020 10:37:47 上午 com.mchange.v2.async.ThreadPoolAsynchronousRunner$DeadlockDetector run

警告: com.mchange.v2.async.ThreadPoolAsynchronousRunner$DeadlockDetector@1f407bb -- APPARENT DEADLOCK!!! Creating emergency threads for unassigned pending tasks!

六月 19, 2020 10:37:47 上午 com.mchange.v2.async.ThreadPoolAsynchronousRunner$DeadlockDetector run

警告: com.mchange.v2.async.ThreadPoolAsynchronousRunner$DeadlockDetector@1f407bb -- APPARENT DEADLOCK!!! Complete Status: 

Managed Threads: 3

Active Threads: 3

Active Tasks: 

com.mchange.v2.resourcepool.BasicResourcePool$AcquireTask@4e0ee3ce (com.mchange.v2.async.ThreadPoolAsynchronousRunner$PoolThread-#0)

com.mchange.v2.resourcepool.BasicResourcePool$AcquireTask@6fe6fc6b (com.mchange.v2.async.ThreadPoolAsynchronousRunner$PoolThread-#1)

com.mchange.v2.resourcepool.BasicResourcePool$AcquireTask@7f0acc23 (com.mchange.v2.async.ThreadPoolAsynchronousRunner$PoolThread-#2)

Pending Tasks: 

com.mchange.v2.resourcepool.BasicResourcePool$AcquireTask@17088d3d

com.mchange.v2.resourcepool.BasicResourcePool$AcquireTask@2e211c81

com.mchange.v2.resourcepool.BasicResourcePool$AcquireTask@767ca88a

com.mchange.v2.resourcepool.BasicResourcePool$AcquireTask@5fbe09b2

com.mchange.v2.resourcepool.BasicResourcePool$AcquireTask@c0c061d

com.mchange.v2.resourcepool.BasicResourcePool$AcquireTask@2a6fc609

com.mchange.v2.resourcepool.BasicResourcePool$AcquireTask@39440336

Pool thread stack traces:

Thread[com.mchange.v2.async.ThreadPoolAsynchronousRunner$PoolThread-#0,5,main]

java.lang.Thread.sleep(Native Method)

com.mchange.v2.resourcepool.BasicResourcePool$AcquireTask.run(BasicResourcePool.java:1805)

com.mchange.v2.async.ThreadPoolAsynchronousRunner$PoolThread.run(ThreadPoolAsynchronousRunner.java:547)

Thread[com.mchange.v2.async.ThreadPoolAsynchronousRunner$PoolThread-#1,5,main]

java.lang.Thread.sleep(Native Method)

com.mchange.v2.resourcepool.BasicResourcePool$AcquireTask.run(BasicResourcePool.java:1805)

com.mchange.v2.async.ThreadPoolAsynchronousRunner$PoolThread.run(ThreadPoolAsynchronousRunner.java:547)

Thread[com.mchange.v2.async.ThreadPoolAsynchronousRunner$PoolThread-#2,5,main]

java.lang.Thread.sleep(Native Method)

com.mchange.v2.resourcepool.BasicResourcePool$AcquireTask.run(BasicResourcePool.java:1805)

com.mchange.v2.async.ThreadPoolAsynchronousRunner$PoolThread.run(ThreadPoolAsynchronousRunner.java:547)

六月 19, 2020 10:37:56 上午 com.mchange.v2.resourcepool.BasicResourcePool$AcquireTask run

警告: com.mchange.v2.resourcepool.BasicResourcePool$AcquireTask@4e0ee3ce -- Acquisition Attempt Failed!!! Clearing pending acquires. While trying to acquire a needed new resource, we failed to succeed more than the maximum number of allowed acquisition attempts (30). Last acquisition attempt exception: 

java.sql.SQLException: No suitable driver

at java.sql.DriverManager.getDriver(DriverManager.java:315)

at com.mchange.v2.c3p0.DriverManagerDataSource.driver(DriverManagerDataSource.java:223)

at com.mchange.v2.c3p0.DriverManagerDataSource.getConnection(DriverManagerDataSource.java:134)

at com.mchange.v2.c3p0.WrapperConnectionPoolDataSource.getPooledConnection(WrapperConnectionPoolDataSource.java:182)

at com.mchange.v2.c3p0.WrapperConnectionPoolDataSource.getPooledConnection(WrapperConnectionPoolDataSource.java:171)

at com.mchange.v2.c3p0.impl.C3P0PooledConnectionPool$1PooledConnectionResourcePoolManager.acquireResource(C3P0PooledConnectionPool.java:137)

at com.mchange.v2.resourcepool.BasicResourcePool.doAcquire(BasicResourcePool.java:1014)

at com.mchange.v2.resourcepool.BasicResourcePool.access$800(BasicResourcePool.java:32)

at com.mchange.v2.resourcepool.BasicResourcePool$AcquireTask.run(BasicResourcePool.java:1810)

at com.mchange.v2.async.ThreadPoolAsynchronousRunner$PoolThread.run(ThreadPoolAsynchronousRunner.java:547)

六月 19, 2020 10:37:56 上午 com.mchange.v2.resourcepool.BasicResourcePool$AcquireTask run

警告: com.mchange.v2.resourcepool.BasicResourcePool$AcquireTask@7f0acc23 -- Acquisition Attempt Failed!!! Clearing pending acquires. While trying to acquire a needed new resource, we failed to succeed more than the maximum number of allowed acquisition attempts (30). Last acquisition attempt exception: 

java.sql.SQLException: No suitable driver

at java.sql.DriverManager.getDriver(DriverManager.java:315)

at com.mchange.v2.c3p0.DriverManagerDataSource.driver(DriverManagerDataSource.java:223)

at com.mchange.v2.c3p0.DriverManagerDataSource.getConnection(DriverManagerDataSource.java:134)

at com.mchange.v2.c3p0.WrapperConnectionPoolDataSource.getPooledConnection(WrapperConnectionPoolDataSource.java:182)

at com.mchange.v2.c3p0.WrapperConnectionPoolDataSource.getPooledConnection(WrapperConnectionPoolDataSource.java:171)

at com.mchange.v2.c3p0.impl.C3P0PooledConnectionPool$1PooledConnectionResourcePoolManager.acquireResource(C3P0PooledConnectionPool.java:137)

at com.mchange.v2.resourcepool.BasicResourcePool.doAcquire(BasicResourcePool.java:1014)

at com.mchange.v2.resourcepool.BasicResourcePool.access$800(BasicResourcePool.java:32)

at com.mchange.v2.resourcepool.BasicResourcePool$AcquireTask.run(BasicResourcePool.java:1810)

at com.mchange.v2.async.ThreadPoolAsynchronousRunner$PoolThread.run(ThreadPoolAsynchronousRunner.java:547)

六月 19, 2020 10:37:56 上午 com.mchange.v2.resourcepool.BasicResourcePool$AcquireTask run

警告: com.mchange.v2.resourcepool.BasicResourcePool$AcquireTask@6fe6fc6b -- Acquisition Attempt Failed!!! Clearing pending acquires. While trying to acquire a needed new resource, we failed to succeed more than the maximum number of allowed acquisition attempts (30). Last acquisition attempt exception: 

java.sql.SQLException: No suitable driver

at java.sql.DriverManager.getDriver(DriverManager.java:315)

at com.mchange.v2.c3p0.DriverManagerDataSource.driver(DriverManagerDataSource.java:223)

at com.mchange.v2.c3p0.DriverManagerDataSource.getConnection(DriverManagerDataSource.java:134)

at com.mchange.v2.c3p0.WrapperConnectionPoolDataSource.getPooledConnection(WrapperConnectionPoolDataSource.java:182)

at com.mchange.v2.c3p0.WrapperConnectionPoolDataSource.getPooledConnection(WrapperConnectionPoolDataSource.java:171)

at com.mchange.v2.c3p0.impl.C3P0PooledConnectionPool$1PooledConnectionResourcePoolManager.acquireResource(C3P0PooledConnectionPool.java:137)

at com.mchange.v2.resourcepool.BasicResourcePool.doAcquire(BasicResourcePool.java:1014)

at com.mchange.v2.resourcepool.BasicResourcePool.access$800(BasicResourcePool.java:32)

at com.mchange.v2.resourcepool.BasicResourcePool$AcquireTask.run(BasicResourcePool.java:1810)

at com.mchange.v2.async.ThreadPoolAsynchronousRunner$PoolThread.run(ThreadPoolAsynchronousRunner.java:547)

java.sql.SQLException: Connections could not be acquired from the underlying database!

at com.mchange.v2.sql.SqlUtils.toSQLException(SqlUtils.java:106)

at com.mchange.v2.c3p0.impl.C3P0PooledConnectionPool.checkoutPooledConnection(C3P0PooledConnectionPool.java:529)

at com.mchange.v2.c3p0.impl.AbstractPoolBackedDataSource.getConnection(AbstractPoolBackedDataSource.java:128)

at com.bjsxt7.connection.C3P0Test.testGetConnection1(C3P0Test.java:31)

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.junit.runners.model.FrameworkMethod$1.runReflectiveCall(FrameworkMethod.java:50)

at org.junit.internal.runners.model.ReflectiveCallable.run(ReflectiveCallable.java:12)

at org.junit.runners.model.FrameworkMethod.invokeExplosively(FrameworkMethod.java:47)

at org.junit.internal.runners.statements.InvokeMethod.evaluate(InvokeMethod.java:17)

at org.junit.runners.ParentRunner.runLeaf(ParentRunner.java:325)

at org.junit.runners.BlockJUnit4ClassRunner.runChild(BlockJUnit4ClassRunner.java:78)

at org.junit.runners.BlockJUnit4ClassRunner.runChild(BlockJUnit4ClassRunner.java:57)

at org.junit.runners.ParentRunner$3.run(ParentRunner.java:290)

at org.junit.runners.ParentRunner$1.schedule(ParentRunner.java:71)

at org.junit.runners.ParentRunner.runChildren(ParentRunner.java:288)

at org.junit.runners.ParentRunner.access$000(ParentRunner.java:58)

at org.junit.runners.ParentRunner$2.evaluate(ParentRunner.java:268)

at org.junit.runners.ParentRunner.run(ParentRunner.java:363)

at org.junit.runner.JUnitCore.run(JUnitCore.java:137)

at com.intellij.junit4.JUnit4IdeaTestRunner.startRunnerWithArgs(JUnit4IdeaTestRunner.java:68)

at com.intellij.rt.junit.IdeaTestRunner$Repeater.startRunnerWithArgs(IdeaTestRunner.java:33)

at com.intellij.rt.junit.JUnitStarter.prepareStreamsAndStart(JUnitStarter.java:230)

at com.intellij.rt.junit.JUnitStarter.main(JUnitStarter.java:58)

Caused by: com.mchange.v2.resourcepool.CannotAcquireResourceException: A ResourcePool could not acquire a resource from its primary factory or source.

at com.mchange.v2.resourcepool.BasicResourcePool.awaitAvailable(BasicResourcePool.java:1319)

at com.mchange.v2.resourcepool.BasicResourcePool.prelimCheckoutResource(BasicResourcePool.java:557)

at com.mchange.v2.resourcepool.BasicResourcePool.checkoutResource(BasicResourcePool.java:477)

at com.mchange.v2.c3p0.impl.C3P0PooledConnectionPool.checkoutPooledConnection(C3P0PooledConnectionPool.java:525)

... 24 more

Process finished with exit code -1

老师这个数据库昨天还可以登录，今天登录不进去，显示无监听程序，我重新配置服务器时，发现更改登录登不进去，请问一下这是什么原因

怎么我的这个一直下不完了呢？

老师，这个之前写的是5、wangliu那条，后来视频里是没保存，我是把内容删了，为什么我删完之后打开表中仍有这行，但是去设计表里面查看显示只有四行。

老师，麻烦帮我看一下代码，一直显示错误，debug好多次了。谢谢！

老师，为啥今天打开时候突然出现这个，是说还有5天就不能用了？这个咋办啊，我当时就是按照视频中一样安装的，是哪个环节出问题了么？

oracle中创建表Name时不可定义表列名name,报错ORA-00904;

是因为name是关键字吗？那需要使用name需要加“”，可老师没加啊？

为什么我看视频就有滋滋滋电流声，听音乐就没有，用的蓝牙耳机，怎么回事