java.lang.ClassNotFoundException: com.mysql.jdbc.Driver报错 [问题点数:20分,结帖人H191329610]

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错误:java.lang.ClassNotFoundException: com.mysql.cj.jdbc.Driver

关于这个问题,我找了一下资料,其实就是MySQL版本和配置的区别问题 <em>com</em>.<em>mysql</em>.<em>jdbc</em>.<em>Driver</em> 是 <em>mysql</em>-connector-<em>java</em> 5中的 JDBC连接Mysql5 <em>com</em>.<em>mysql</em>.<em>jdbc</em>.<em>Driver</em>: org.quartz.dataSource.qzDS.driver:<em>com</em>.<em>mysql</em>.<em>jdbc</em>.<em>Driver</em> org.quartz.dataSource.q...

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我们做JavaWeb项目连接MySQL数据库时Eclipse控制台如果出现类似下面的异常提示: <em>java</em>.<em>lang</em>.<em>ClassNotFoundException</em>: <em>com</em>.<em>mysql</em>.<em>jdbc</em>.<em>Driver</em> at org.apache.catalina.loader.WebappClassLoader.loadClass(WebappClassLoader.<em>java</em>:1647) at org....

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java.lang.ClassNotFoundException: com.mysql.jdbc.Driver解决方法

Exception in thread &quot;main&quot; <em>java</em>.<em>lang</em>.<em>ClassNotFoundException</em>: <em>com</em>.<em>mysql</em>.<em>jdbc</em>.<em>Driver</em>         at <em>java</em>.net.URLClassLoader.findClass(Unknown Source)         at <em>java</em>.<em>lang</em>.ClassLoader.loadClass(Unknown Sourc...

java.lang.ClassNotFoundException:com.mysql.jdbc.Driver解决方法

折腾了很久,终于在网上找到了错误的原因。这里也发一篇帮助广大新手指导如何解决。 原因是tomcat找不到<em>mysql</em> jar包的问题。 在<em>java</em>项目中,只需要引入<em>mysql</em>-connector-<em>java</em>-5.1.7-bin.jar就可以运行<em>java</em>项目。 在web项目中,当Class.forName("om.<em>mysql</em>.<em>jdbc</em>.<em>Driver</em>");时myeclipse是不会去查找字符串,不会

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java.lang.ClassNotFoundException: com.mysql.jdbc.Driver的解决方式

引入了包,并且没有任何错误。 据说要把这个jar引入到中但是我发现无论如何都引入不进去,最后找到了一种解决方式——右键项目文件点击Properties 如图 点击add 选择<em>java</em> build path entries 这个时候选择你的jar包 最后就解决了 不知道什么原因望指点!! ...

java.lang.ClassNotFoundException: com.mysql.jdbc.Driver解决方案

在写一个简单的连接数据库程序时出现以下错误 <em>java</em>.<em>lang</em>.<em>ClassNotFoundException</em>: <em>com</em>.<em>mysql</em>.<em>jdbc</em>.<em>Driver</em> at <em>java</em>.base/jdk.internal.loader.BuiltinClassLoader.loadClass(BuiltinClassLoader.<em>java</em>:582) at <em>java</em>.base/j...

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IDEA如何载入JDBC驱动,连接MySQL java.lang.ClassNotFoundException:com.mysql.jdbc.Driver

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Could not load driverClass com.mysql.jbdc.Driver,配置好jar了还是找不到

自学线上商城的<em>java</em> web 项目。今天一个下午都在调这个bug,也试过调试jar包,也有重新配置Tomcat与<em>mysql</em>的连接池 我也有把<em>jdbc</em>的包放在jdk的lib文件夹下,然后增加classpath,jre的ext都试过 还看了新的<em>jdbc</em>是<em>com</em>.<em>mysql</em>.cj.<em>jdbc</em>.<em>Driver</em>也试过,似乎都没什么用 在maven和Tomcat的列表里都有<em>jdbc</em>的jar包,包括我自己有新build path也增加了这些jar包,而且我把好几个版本的都放上去了(不知道会不会是这个影响,不过加了也删不掉),pom.xml里面配的是截图中的8.0.17 ![图片说明](https://img-ask.csdn.net/upload/201908/02/1564760377_14775.png) ********** 如果需要更多信息我也可以再加,感激不尽 ## <em>报错</em>信息如下:********** ``` 8月 02, 2019 11:30:38 下午 <em>com</em>.mchange.v2.c3p0.impl.AbstractPoolBackedDataSource getPoolManager 信息: Initializing c3p0 pool... <em>com</em>.mchange.v2.c3p0.ComboPooledDataSource [ acquireIncrement -> 3, acquireRetryAttempts -> 2, acquireRetryDelay -> 1000, autoCommitOnClose -> false, automaticTestTable -> null, breakAfterAcquireFailure -> false, checkoutTimeout -> 10000, connectionCustomizerClassName -> null, connectionTesterClassName -> <em>com</em>.mchange.v2.c3p0.impl.DefaultConnectionTester, dataSourceName -> 1hge162a4n0lvdz1eiiv1j|6ccdb29f, debugUnreturnedConnectionStackTraces -> false, description -> null, driverClass -> <em>com</em>.<em>mysql</em>.jbdc.<em>Driver</em>, factoryClassLocation -> null, forceIgnoreUnresolvedTransactions -> false, identityToken -> 1hge162a4n0lvdz1eiiv1j|6ccdb29f, idleConnectionTestPeriod -> 0, initialPoolSize -> 3, <em>jdbc</em>Url -> <em>jdbc</em>:<em>mysql</em>://localhost:3306/todoList?useUnicode=true&characterEncoding=utf8&serverTimezone=GMT&useSSL=false, maxAdministrativeTaskTime -> 0, maxConnectionAge -> 0, maxIdleTime -> 0, maxIdleTimeExcessConnections -> 0, maxPoolSize -> 30, maxStatements -> 0, maxStatementsPerConnection -> 0, minPoolSize -> 10, numHelperThreads -> 3, numThreadsAwaitingCheckoutDefaultUser -> 0, preferredTestQuery -> null, properties -> {password=******, user=******}, propertyCycle -> 0, testConnectionOnCheckin -> false, testConnectionOnCheckout -> false, unreturnedConnectionTimeout -> 0, usesTraditionalReflectiveProxies -> false ] 8月 02, 2019 11:30:38 下午 <em>com</em>.mchange.v2.c3p0.<em>Driver</em>ManagerDataSource ensure<em>Driver</em>Loaded 警告: Could not load driverClass <em>com</em>.<em>mysql</em>.jbdc.<em>Driver</em> <em>java</em>.<em>lang</em>.<em>ClassNotFoundException</em>: <em>com</em>.<em>mysql</em>.jbdc.<em>Driver</em> at <em>java</em>.base/jdk.internal.loader.BuiltinClassLoader.loadClass(BuiltinClassLoader.<em>java</em>:583) at <em>java</em>.base/jdk.internal.loader.ClassLoaders$AppClassLoader.loadClass(ClassLoaders.<em>java</em>:178) at <em>java</em>.base/<em>java</em>.<em>lang</em>.ClassLoader.loadClass(ClassLoader.<em>java</em>:521) at <em>java</em>.base/<em>java</em>.<em>lang</em>.Class.forName0(Native Method) at <em>java</em>.base/<em>java</em>.<em>lang</em>.Class.forName(Class.<em>java</em>:332) at <em>com</em>.mchange.v2.c3p0.<em>Driver</em>ManagerDataSource.ensure<em>Driver</em>Loaded(<em>Driver</em>ManagerDataSource.<em>java</em>:100) at <em>com</em>.mchange.v2.c3p0.<em>Driver</em>ManagerDataSource.getConnection(<em>Driver</em>ManagerDataSource.<em>java</em>:132) at <em>com</em>.mchange.v2.c3p0.WrapperConnectionPoolDataSource.getPooledConnection(WrapperConnectionPoolDataSource.<em>java</em>:182) at <em>com</em>.mchange.v2.c3p0.WrapperConnectionPoolDataSource.getPooledConnection(WrapperConnectionPoolDataSource.<em>java</em>:171) at <em>com</em>.mchange.v2.c3p0.impl.C3P0PooledConnectionPool$1PooledConnectionResourcePoolManager.acquireResource(C3P0PooledConnectionPool.<em>java</em>:137) at <em>com</em>.mchange.v2.resourcepool.BasicResourcePool.doAcquire(BasicResourcePool.<em>java</em>:1014) at <em>com</em>.mchange.v2.resourcepool.BasicResourcePool.access$800(BasicResourcePool.<em>java</em>:32) at <em>com</em>.mchange.v2.resourcepool.BasicResourcePool$AcquireTask.run(BasicResourcePool.<em>java</em>:1810) at <em>com</em>.mchange.v2.async.ThreadPoolAsynchronousRunner$PoolThread.run(ThreadPoolAsynchronousRunner.<em>java</em>:547) 8月 02, 2019 11:30:38 下午 <em>com</em>.mchange.v2.c3p0.<em>Driver</em>ManagerDataSource ensure<em>Driver</em>Loaded 警告: Could not load driverClass <em>com</em>.<em>mysql</em>.jbdc.<em>Driver</em> <em>java</em>.<em>lang</em>.<em>ClassNotFoundException</em>: <em>com</em>.<em>mysql</em>.jbdc.<em>Driver</em> at <em>java</em>.base/jdk.internal.loader.BuiltinClassLoader.loadClass(BuiltinClassLoader.<em>java</em>:583) at <em>java</em>.base/jdk.internal.loader.ClassLoaders$AppClassLoader.loadClass(ClassLoaders.<em>java</em>:178) at <em>java</em>.base/<em>java</em>.<em>lang</em>.ClassLoader.loadClass(ClassLoader.<em>java</em>:521) at <em>java</em>.base/<em>java</em>.<em>lang</em>.Class.forName0(Native Method) at <em>java</em>.base/<em>java</em>.<em>lang</em>.Class.forName(Class.<em>java</em>:332) at <em>com</em>.mchange.v2.c3p0.<em>Driver</em>ManagerDataSource.ensure<em>Driver</em>Loaded(<em>Driver</em>ManagerDataSource.<em>java</em>:100) at <em>com</em>.mchange.v2.c3p0.<em>Driver</em>ManagerDataSource.getConnection(<em>Driver</em>ManagerDataSource.<em>java</em>:132) at <em>com</em>.mchange.v2.c3p0.WrapperConnectionPoolDataSource.getPooledConnection(WrapperConnectionPoolDataSource.<em>java</em>:182) at <em>com</em>.mchange.v2.c3p0.WrapperConnectionPoolDataSource.getPooledConnection(WrapperConnectionPoolDataSource.<em>java</em>:171) at <em>com</em>.mchange.v2.c3p0.impl.C3P0PooledConnectionPool$1PooledConnectionResourcePoolManager.acquireResource(C3P0PooledConnectionPool.<em>java</em>:137) at <em>com</em>.mchange.v2.resourcepool.BasicResourcePool.doAcquire(BasicResourcePool.<em>java</em>:1014) at <em>com</em>.mchange.v2.resourcepool.BasicResourcePool.access$800(BasicResourcePool.<em>java</em>:32) at <em>com</em>.mchange.v2.resourcepool.BasicResourcePool$AcquireTask.run(BasicResourcePool.<em>java</em>:1810) at <em>com</em>.mchange.v2.async.ThreadPoolAsynchronousRunner$PoolThread.run(ThreadPoolAsynchronousRunner.<em>java</em>:547) 8月 02, 2019 11:30:38 下午 <em>com</em>.mchange.v2.c3p0.<em>Driver</em>ManagerDataSource ensure<em>Driver</em>Loaded 警告: Could not load driverClass <em>com</em>.<em>mysql</em>.jbdc.<em>Driver</em> <em>java</em>.<em>lang</em>.<em>ClassNotFoundException</em>: <em>com</em>.<em>mysql</em>.jbdc.<em>Driver</em> at <em>java</em>.base/jdk.internal.loader.BuiltinClassLoader.loadClass(BuiltinClassLoader.<em>java</em>:583) at <em>java</em>.base/jdk.internal.loader.ClassLoaders$AppClassLoader.loadClass(ClassLoaders.<em>java</em>:178) at <em>java</em>.base/<em>java</em>.<em>lang</em>.ClassLoader.loadClass(ClassLoader.<em>java</em>:521) at <em>java</em>.base/<em>java</em>.<em>lang</em>.Class.forName0(Native Method) at <em>java</em>.base/<em>java</em>.<em>lang</em>.Class.forName(Class.<em>java</em>:332) at <em>com</em>.mchange.v2.c3p0.<em>Driver</em>ManagerDataSource.ensure<em>Driver</em>Loaded(<em>Driver</em>ManagerDataSource.<em>java</em>:100) at <em>com</em>.mchange.v2.c3p0.<em>Driver</em>ManagerDataSource.getConnection(<em>Driver</em>ManagerDataSource.<em>java</em>:132) at <em>com</em>.mchange.v2.c3p0.WrapperConnectionPoolDataSource.getPooledConnection(WrapperConnectionPoolDataSource.<em>java</em>:182) at <em>com</em>.mchange.v2.c3p0.WrapperConnectionPoolDataSource.getPooledConnection(WrapperConnectionPoolDataSource.<em>java</em>:171) at <em>com</em>.mchange.v2.c3p0.impl.C3P0PooledConnectionPool$1PooledConnectionResourcePoolManager.acquireResource(C3P0PooledConnectionPool.<em>java</em>:137) at <em>com</em>.mchange.v2.resourcepool.BasicResourcePool.doAcquire(BasicResourcePool.<em>java</em>:1014) at <em>com</em>.mchange.v2.resourcepool.BasicResourcePool.access$800(BasicResourcePool.<em>java</em>:32) at <em>com</em>.mchange.v2.resourcepool.BasicResourcePool$AcquireTask.run(BasicResourcePool.<em>java</em>:1810) at <em>com</em>.mchange.v2.async.ThreadPoolAsynchronousRunner$PoolThread.run(ThreadPoolAsynchronousRunner.<em>java</em>:547) 8月 02, 2019 11:30:40 下午 <em>com</em>.mchange.v2.c3p0.<em>Driver</em>ManagerDataSource ensure<em>Driver</em>Loaded 警告: Could not load driverClass <em>com</em>.<em>mysql</em>.jbdc.<em>Driver</em> <em>java</em>.<em>lang</em>.<em>ClassNotFoundException</em>: <em>com</em>.<em>mysql</em>.jbdc.<em>Driver</em> at <em>java</em>.base/jdk.internal.loader.BuiltinClassLoader.loadClass(BuiltinClassLoader.<em>java</em>:583) at <em>java</em>.base/jdk.internal.loader.ClassLoaders$AppClassLoader.loadClass(ClassLoaders.<em>java</em>:178) at <em>java</em>.base/<em>java</em>.<em>lang</em>.ClassLoader.loadClass(ClassLoader.<em>java</em>:521) at <em>java</em>.base/<em>java</em>.<em>lang</em>.Class.forName0(Native Method) at <em>java</em>.base/<em>java</em>.<em>lang</em>.Class.forName(Class.<em>java</em>:332) at <em>com</em>.mchange.v2.c3p0.<em>Driver</em>ManagerDataSource.ensure<em>Driver</em>Loaded(<em>Driver</em>ManagerDataSource.<em>java</em>:100) at <em>com</em>.mchange.v2.c3p0.<em>Driver</em>ManagerDataSource.getConnection(<em>Driver</em>ManagerDataSource.<em>java</em>:132) at <em>com</em>.mchange.v2.c3p0.WrapperConnectionPoolDataSource.getPooledConnection(WrapperConnectionPoolDataSource.<em>java</em>:182) at <em>com</em>.mchange.v2.c3p0.WrapperConnectionPoolDataSource.getPooledConnection(WrapperConnectionPoolDataSource.<em>java</em>:171) at <em>com</em>.mchange.v2.c3p0.impl.C3P0PooledConnectionPool$1PooledConnectionResourcePoolManager.acquireResource(C3P0PooledConnectionPool.<em>java</em>:137) at <em>com</em>.mchange.v2.resourcepool.BasicResourcePool.doAcquire(BasicResourcePool.<em>java</em>:1014) at <em>com</em>.mchange.v2.resourcepool.BasicResourcePool.access$800(BasicResourcePool.<em>java</em>:32) at <em>com</em>.mchange.v2.resourcepool.BasicResourcePool$AcquireTask.run(BasicResourcePool.<em>java</em>:1810) at <em>com</em>.mchange.v2.async.ThreadPoolAsynchronousRunner$PoolThread.run(ThreadPoolAsynchronousRunner.<em>java</em>:547) 8月 02, 2019 11:30:40 下午 <em>com</em>.mchange.v2.c3p0.<em>Driver</em>ManagerDataSource ensure<em>Driver</em>Loaded 警告: Could not load driverClass <em>com</em>.<em>mysql</em>.jbdc.<em>Driver</em> <em>java</em>.<em>lang</em>.<em>ClassNotFoundException</em>: <em>com</em>.<em>mysql</em>.jbdc.<em>Driver</em> at <em>java</em>.base/jdk.internal.loader.BuiltinClassLoader.loadClass(BuiltinClassLoader.<em>java</em>:583) at <em>java</em>.base/jdk.internal.loader.ClassLoaders$AppClassLoader.loadClass(ClassLoaders.<em>java</em>:178) at <em>java</em>.base/<em>java</em>.<em>lang</em>.ClassLoader.loadClass(ClassLoader.<em>java</em>:521) at <em>java</em>.base/<em>java</em>.<em>lang</em>.Class.forName0(Native Method) at <em>java</em>.base/<em>java</em>.<em>lang</em>.Class.forName(Class.<em>java</em>:332) at <em>com</em>.mchange.v2.c3p0.<em>Driver</em>ManagerDataSource.ensure<em>Driver</em>Loaded(<em>Driver</em>ManagerDataSource.<em>java</em>:100) at <em>com</em>.mchange.v2.c3p0.<em>Driver</em>ManagerDataSource.getConnection(<em>Driver</em>ManagerDataSource.<em>java</em>:132) at <em>com</em>.mchange.v2.c3p0.WrapperConnectionPoolDataSource.getPooledConnection(WrapperConnectionPoolDataSource.<em>java</em>:182) at <em>com</em>.mchange.v2.c3p0.WrapperConnectionPoolDataSource.getPooledConnection(WrapperConnectionPoolDataSource.<em>java</em>:171) at <em>com</em>.mchange.v2.c3p0.impl.C3P0PooledConnectionPool$1PooledConnectionResourcePoolManager.acquireResource(C3P0PooledConnectionPool.<em>java</em>:137) at <em>com</em>.mchange.v2.resourcepool.BasicResourcePool.doAcquire(BasicResourcePool.<em>java</em>:1014) at <em>com</em>.mchange.v2.resourcepool.BasicResourcePool.access$800(BasicResourcePool.<em>java</em>:32) at <em>com</em>.mchange.v2.resourcepool.BasicResourcePool$AcquireTask.run(BasicResourcePool.<em>java</em>:1810) at <em>com</em>.mchange.v2.async.ThreadPoolAsynchronousRunner$PoolThread.run(ThreadPoolAsynchronousRunner.<em>java</em>:547) 8月 02, 2019 11:30:40 下午 <em>com</em>.mchange.v2.c3p0.<em>Driver</em>ManagerDataSource ensure<em>Driver</em>Loaded 警告: Could not load driverClass <em>com</em>.<em>mysql</em>.jbdc.<em>Driver</em> <em>java</em>.<em>lang</em>.<em>ClassNotFoundException</em>: <em>com</em>.<em>mysql</em>.jbdc.<em>Driver</em> at <em>java</em>.base/jdk.internal.loader.BuiltinClassLoader.loadClass(BuiltinClassLoader.<em>java</em>:583) at <em>java</em>.base/jdk.internal.loader.ClassLoaders$AppClassLoader.loadClass(ClassLoaders.<em>java</em>:178) at <em>java</em>.base/<em>java</em>.<em>lang</em>.ClassLoader.loadClass(ClassLoader.<em>java</em>:521) at <em>java</em>.base/<em>java</em>.<em>lang</em>.Class.forName0(Native Method) at <em>java</em>.base/<em>java</em>.<em>lang</em>.Class.forName(Class.<em>java</em>:332) at <em>com</em>.mchange.v2.c3p0.<em>Driver</em>ManagerDataSource.ensure<em>Driver</em>Loaded(<em>Driver</em>ManagerDataSource.<em>java</em>:100) at <em>com</em>.mchange.v2.c3p0.<em>Driver</em>ManagerDataSource.getConnection(<em>Driver</em>ManagerDataSource.<em>java</em>:132) at <em>com</em>.mchange.v2.c3p0.WrapperConnectionPoolDataSource.getPooledConnection(WrapperConnectionPoolDataSource.<em>java</em>:182) at <em>com</em>.mchange.v2.c3p0.WrapperConnectionPoolDataSource.getPooledConnection(WrapperConnectionPoolDataSource.<em>java</em>:171) at <em>com</em>.mchange.v2.c3p0.impl.C3P0PooledConnectionPool$1PooledConnectionResourcePoolManager.acquireResource(C3P0PooledConnectionPool.<em>java</em>:137) at <em>com</em>.mchange.v2.resourcepool.BasicResourcePool.doAcquire(BasicResourcePool.<em>java</em>:1014) at <em>com</em>.mchange.v2.resourcepool.BasicResourcePool.access$800(BasicResourcePool.<em>java</em>:32) at <em>com</em>.mchange.v2.resourcepool.BasicResourcePool$AcquireTask.run(BasicResourcePool.<em>java</em>:1810) at <em>com</em>.mchange.v2.async.ThreadPoolAsynchronousRunner$PoolThread.run(ThreadPoolAsynchronousRunner.<em>java</em>:547) 8月 02, 2019 11:30:40 下午 <em>com</em>.mchange.v2.resourcepool.BasicResourcePool$AcquireTask run 警告: <em>com</em>.mchange.v2.resourcepool.BasicResourcePool$AcquireTask@40eddbb0 -- 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 (2). Last acquisition attempt exception: <em>com</em>.<em>mysql</em>.<em>jdbc</em>.exceptions.<em>jdbc</em>4.MySQLSyntaxErrorException: Unknown database 'todolist' at <em>java</em>.base/jdk.internal.reflect.NativeConstructorAccessorImpl.newInstance0(Native Method) at <em>java</em>.base/jdk.internal.reflect.NativeConstructorAccessorImpl.newInstance(NativeConstructorAccessorImpl.<em>java</em>:62) at <em>java</em>.base/jdk.internal.reflect.DelegatingConstructorAccessorImpl.newInstance(DelegatingConstructorAccessorImpl.<em>java</em>:45) at <em>java</em>.base/<em>java</em>.<em>lang</em>.reflect.Constructor.newInstanceWithCaller(Constructor.<em>java</em>:500) at <em>java</em>.base/<em>java</em>.<em>lang</em>.reflect.Constructor.newInstance(Constructor.<em>java</em>:481) at <em>com</em>.<em>mysql</em>.<em>jdbc</em>.Util.handleNewInstance(Util.<em>java</em>:425) at <em>com</em>.<em>mysql</em>.<em>jdbc</em>.Util.getInstance(Util.<em>java</em>:408) at <em>com</em>.<em>mysql</em>.<em>jdbc</em>.SQLError.createSQLException(SQLError.<em>java</em>:944) at <em>com</em>.<em>mysql</em>.<em>jdbc</em>.MysqlIO.checkErrorPacket(MysqlIO.<em>java</em>:3978) at <em>com</em>.<em>mysql</em>.<em>jdbc</em>.MysqlIO.checkErrorPacket(MysqlIO.<em>java</em>:3914) at <em>com</em>.<em>mysql</em>.<em>jdbc</em>.MysqlIO.checkErrorPacket(MysqlIO.<em>java</em>:871) at <em>com</em>.<em>mysql</em>.<em>jdbc</em>.MysqlIO.proceedHandshakeWithPluggableAuthentication(MysqlIO.<em>java</em>:1714) at <em>com</em>.<em>mysql</em>.<em>jdbc</em>.MysqlIO.doHandshake(MysqlIO.<em>java</em>:1224) at <em>com</em>.<em>mysql</em>.<em>jdbc</em>.ConnectionImpl.coreConnect(ConnectionImpl.<em>java</em>:2199) at <em>com</em>.<em>mysql</em>.<em>jdbc</em>.ConnectionImpl.connectOneTryOnly(ConnectionImpl.<em>java</em>:2230) at <em>com</em>.<em>mysql</em>.<em>jdbc</em>.ConnectionImpl.createNewIO(ConnectionImpl.<em>java</em>:2025) at <em>com</em>.<em>mysql</em>.<em>jdbc</em>.ConnectionImpl.(ConnectionImpl.<em>java</em>:778) at <em>com</em>.<em>mysql</em>.<em>jdbc</em>.JDBC4Connection.(JDBC4Connection.<em>java</em>:47) at <em>java</em>.base/jdk.internal.reflect.NativeConstructorAccessorImpl.newInstance0(Native Method) at <em>java</em>.base/jdk.internal.reflect.NativeConstructorAccessorImpl.newInstance(NativeConstructorAccessorImpl.<em>java</em>:62) at <em>java</em>.base/jdk.internal.reflect.DelegatingConstructorAccessorImpl.newInstance(DelegatingConstructorAccessorImpl.<em>java</em>:45) at <em>java</em>.base/<em>java</em>.<em>lang</em>.reflect.Constructor.newInstanceWithCaller(Constructor.<em>java</em>:500) at <em>java</em>.base/<em>java</em>.<em>lang</em>.reflect.Constructor.newInstance(Constructor.<em>java</em>:481) at <em>com</em>.<em>mysql</em>.<em>jdbc</em>.Util.handleNewInstance(Util.<em>java</em>:425) at <em>com</em>.<em>mysql</em>.<em>jdbc</em>.ConnectionImpl.getInstance(ConnectionImpl.<em>java</em>:386) at <em>com</em>.<em>mysql</em>.<em>jdbc</em>.NonRegistering<em>Driver</em>.connect(NonRegistering<em>Driver</em>.<em>java</em>:330) at <em>com</em>.mchange.v2.c3p0.<em>Driver</em>ManagerDataSource.getConnection(<em>Driver</em>ManagerDataSource.<em>java</em>:134) at <em>com</em>.mchange.v2.c3p0.WrapperConnectionPoolDataSource.getPooledConnection(WrapperConnectionPoolDataSource.<em>java</em>:182) at <em>com</em>.mchange.v2.c3p0.WrapperConnectionPoolDataSource.getPooledConnection(WrapperConnectionPoolDataSource.<em>java</em>:171) at <em>com</em>.mchange.v2.c3p0.impl.C3P0PooledConnectionPool$1PooledConnectionResourcePoolManager.acquireResource(C3P0PooledConnectionPool.<em>java</em>:137) at <em>com</em>.mchange.v2.resourcepool.BasicResourcePool.doAcquire(BasicResourcePool.<em>java</em>:1014) at <em>com</em>.mchange.v2.resourcepool.BasicResourcePool.access$800(BasicResourcePool.<em>java</em>:32) at <em>com</em>.mchange.v2.resourcepool.BasicResourcePool$AcquireTask.run(BasicResourcePool.<em>java</em>:1810) at <em>com</em>.mchange.v2.async.ThreadPoolAsynchronousRunner$PoolThread.run(ThreadPoolAsynchronousRunner.<em>java</em>:547) 8月 02, 2019 11:30:40 下午 <em>com</em>.mchange.v2.resourcepool.BasicResourcePool$AcquireTask run 警告: <em>com</em>.mchange.v2.resourcepool.BasicResourcePool$AcquireTask@45eae662 -- 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 (2). Last acquisition attempt exception: <em>com</em>.<em>mysql</em>.<em>jdbc</em>.exceptions.<em>jdbc</em>4.MySQLSyntaxErrorException: Unknown database 'todolist' at <em>java</em>.base/jdk.internal.reflect.NativeConstructorAccessorImpl.newInstance0(Native Method) at <em>java</em>.base/jdk.internal.reflect.NativeConstructorAccessorImpl.newInstance(NativeConstructorAccessorImpl.<em>java</em>:62) at <em>java</em>.base/jdk.internal.reflect.DelegatingConstructorAccessorImpl.newInstance(DelegatingConstructorAccessorImpl.<em>java</em>:45) at <em>java</em>.base/<em>java</em>.<em>lang</em>.reflect.Constructor.newInstanceWithCaller(Constructor.<em>java</em>:500) at <em>java</em>.base/<em>java</em>.<em>lang</em>.reflect.Constructor.newInstance(Constructor.<em>java</em>:481) at <em>com</em>.<em>mysql</em>.<em>jdbc</em>.Util.handleNewInstance(Util.<em>java</em>:425) at <em>com</em>.<em>mysql</em>.<em>jdbc</em>.Util.getInstance(Util.<em>java</em>:408) at <em>com</em>.<em>mysql</em>.<em>jdbc</em>.SQLError.createSQLException(SQLError.<em>java</em>:944) at <em>com</em>.<em>mysql</em>.<em>jdbc</em>.MysqlIO.checkErrorPacket(MysqlIO.<em>java</em>:3978) at <em>com</em>.<em>mysql</em>.<em>jdbc</em>.MysqlIO.checkErrorPacket(MysqlIO.<em>java</em>:3914) at <em>com</em>.<em>mysql</em>.<em>jdbc</em>.MysqlIO.checkErrorPacket(MysqlIO.<em>java</em>:871) at <em>com</em>.<em>mysql</em>.<em>jdbc</em>.MysqlIO.proceedHandshakeWithPluggableAuthentication(MysqlIO.<em>java</em>:1714) at <em>com</em>.<em>mysql</em>.<em>jdbc</em>.MysqlIO.doHandshake(MysqlIO.<em>java</em>:1224) at <em>com</em>.<em>mysql</em>.<em>jdbc</em>.ConnectionImpl.coreConnect(ConnectionImpl.<em>java</em>:2199) at <em>com</em>.<em>mysql</em>.<em>jdbc</em>.ConnectionImpl.connectOneTryOnly(ConnectionImpl.<em>java</em>:2230) at <em>com</em>.<em>mysql</em>.<em>jdbc</em>.ConnectionImpl.createNewIO(ConnectionImpl.<em>java</em>:2025) at <em>com</em>.<em>mysql</em>.<em>jdbc</em>.ConnectionImpl.(ConnectionImpl.<em>java</em>:778) at <em>com</em>.<em>mysql</em>.<em>jdbc</em>.JDBC4Connection.(JDBC4Connection.<em>java</em>:47) at <em>java</em>.base/jdk.internal.reflect.NativeConstructorAccessorImpl.newInstance0(Native Method) at <em>java</em>.base/jdk.internal.reflect.NativeConstructorAccessorImpl.newInstance(NativeConstructorAccessorImpl.<em>java</em>:62) at <em>java</em>.base/jdk.internal.reflect.DelegatingConstructorAccessorImpl.newInstance(DelegatingConstructorAccessorImpl.<em>java</em>:45) at <em>java</em>.base/<em>java</em>.<em>lang</em>.reflect.Constructor.newInstanceWithCaller(Constructor.<em>java</em>:500) at <em>java</em>.base/<em>java</em>.<em>lang</em>.reflect.Constructor.newInstance(Constructor.<em>java</em>:481) at <em>com</em>.<em>mysql</em>.<em>jdbc</em>.Util.handleNewInstance(Util.<em>java</em>:425) at <em>com</em>.<em>mysql</em>.<em>jdbc</em>.ConnectionImpl.getInstance(ConnectionImpl.<em>java</em>:386) at <em>com</em>.<em>mysql</em>.<em>jdbc</em>.NonRegistering<em>Driver</em>.connect(NonRegistering<em>Driver</em>.<em>java</em>:330) at <em>com</em>.mchange.v2.c3p0.<em>Driver</em>ManagerDataSource.getConnection(<em>Driver</em>ManagerDataSource.<em>java</em>:134) at <em>com</em>.mchange.v2.c3p0.WrapperConnectionPoolDataSource.getPooledConnection(WrapperConnectionPoolDataSource.<em>java</em>:182) at <em>com</em>.mchange.v2.c3p0.WrapperConnectionPoolDataSource.getPooledConnection(WrapperConnectionPoolDataSource.<em>java</em>:171) at <em>com</em>.mchange.v2.c3p0.impl.C3P0PooledConnectionPool$1PooledConnectionResourcePoolManager.acquireResource(C3P0PooledConnectionPool.<em>java</em>:137) at <em>com</em>.mchange.v2.resourcepool.BasicResourcePool.doAcquire(BasicResourcePool.<em>java</em>:1014) at <em>com</em>.mchange.v2.resourcepool.BasicResourcePool.access$800(BasicResourcePool.<em>java</em>:32) at <em>com</em>.mchange.v2.resourcepool.BasicResourcePool$AcquireTask.run(BasicResourcePool.<em>java</em>:1810) at <em>com</em>.mchange.v2.async.ThreadPoolAsynchronousRunner$PoolThread.run(ThreadPoolAsynchronousRunner.<em>java</em>:547) 8月 02, 2019 11:30:40 下午 <em>com</em>.mchange.v2.c3p0.<em>Driver</em>ManagerDataSource ensure<em>Driver</em>Loaded 警告: Could not load driverClass <em>com</em>.<em>mysql</em>.jbdc.<em>Driver</em> <em>java</em>.<em>lang</em>.<em>ClassNotFoundException</em>: <em>com</em>.<em>mysql</em>.jbdc.<em>Driver</em> at <em>java</em>.base/jdk.internal.loader.BuiltinClassLoader.loadClass(BuiltinClassLoader.<em>java</em>:583) at <em>java</em>.base/jdk.internal.loader.ClassLoaders$AppClassLoader.loadClass(ClassLoaders.<em>java</em>:178) at <em>java</em>.base/<em>java</em>.<em>lang</em>.ClassLoader.loadClass(ClassLoader.<em>java</em>:521) at <em>java</em>.base/<em>java</em>.<em>lang</em>.Class.forName0(Native Method) at <em>java</em>.base/<em>java</em>.<em>lang</em>.Class.forName(Class.<em>java</em>:332) at <em>com</em>.mchange.v2.c3p0.<em>Driver</em>ManagerDataSource.ensure<em>Driver</em>Loaded(<em>Driver</em>ManagerDataSource.<em>java</em>:100) at <em>com</em>.mchange.v2.c3p0.<em>Driver</em>ManagerDataSource.getConnection(<em>Driver</em>ManagerDataSource.<em>java</em>:132) at <em>com</em>.mchange.v2.c3p0.WrapperConnectionPoolDataSource.getPooledConnection(WrapperConnectionPoolDataSource.<em>java</em>:182) at <em>com</em>.mchange.v2.c3p0.WrapperConnectionPoolDataSource.getPooledConnection(WrapperConnectionPoolDataSource.<em>java</em>:171) at <em>com</em>.mchange.v2.c3p0.impl.C3P0PooledConnectionPool$1PooledConnectionResourcePoolManager.acquireResource(C3P0PooledConnectionPool.<em>java</em>:137) at <em>com</em>.mchange.v2.resourcepool.BasicResourcePool.doAcquire(BasicResourcePool.<em>java</em>:1014) at <em>com</em>.mchange.v2.resourcepool.BasicResourcePool.access$800(BasicResourcePool.<em>java</em>:32) at <em>com</em>.mchange.v2.resourcepool.BasicResourcePool$AcquireTask.run(BasicResourcePool.<em>java</em>:1810) at <em>com</em>.mchange.v2.async.ThreadPoolAsynchronousRunner$PoolThread.run(ThreadPoolAsynchronousRunner.<em>java</em>:547) 8月 02, 2019 11:30:40 下午 <em>com</em>.mchange.v2.resourcepool.BasicResourcePool$AcquireTask run 警告: <em>com</em>.mchange.v2.resourcepool.BasicResourcePool$AcquireTask@6f8071b9 -- 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 (2). Last acquisition attempt exception: <em>com</em>.<em>mysql</em>.<em>jdbc</em>.exceptions.<em>jdbc</em>4.MySQLSyntaxErrorException: Unknown database 'todolist' at <em>java</em>.base/jdk.internal.reflect.NativeConstructorAccessorImpl.newInstance0(Native Method) at <em>java</em>.base/jdk.internal.reflect.NativeConstructorAccessorImpl.newInstance(NativeConstructorAccessorImpl.<em>java</em>:62) at <em>java</em>.base/jdk.internal.reflect.DelegatingConstructorAccessorImpl.newInstance(DelegatingConstructorAccessorImpl.<em>java</em>:45) at <em>java</em>.base/<em>java</em>.<em>lang</em>.reflect.Constructor.newInstanceWithCaller(Constructor.<em>java</em>:500) at <em>java</em>.base/<em>java</em>.<em>lang</em>.reflect.Constructor.newInstance(Constructor.<em>java</em>:481) at <em>com</em>.<em>mysql</em>.<em>jdbc</em>.Util.handleNewInstance(Util.<em>java</em>:425) at <em>com</em>.<em>mysql</em>.<em>jdbc</em>.Util.getInstance(Util.<em>java</em>:408) at <em>com</em>.<em>mysql</em>.<em>jdbc</em>.SQLError.createSQLException(SQLError.<em>java</em>:944) at <em>com</em>.<em>mysql</em>.<em>jdbc</em>.MysqlIO.checkErrorPacket(MysqlIO.<em>java</em>:3978) at <em>com</em>.<em>mysql</em>.<em>jdbc</em>.MysqlIO.checkErrorPacket(MysqlIO.<em>java</em>:3914) at <em>com</em>.<em>mysql</em>.<em>jdbc</em>.MysqlIO.checkErrorPacket(MysqlIO.<em>java</em>:871) at <em>com</em>.<em>mysql</em>.<em>jdbc</em>.MysqlIO.proceedHandshakeWithPluggableAuthentication(MysqlIO.<em>java</em>:1714) at <em>com</em>.<em>mysql</em>.<em>jdbc</em>.MysqlIO.doHandshake(MysqlIO.<em>java</em>:1224) at <em>com</em>.<em>mysql</em>.<em>jdbc</em>.ConnectionImpl.coreConnect(ConnectionImpl.<em>java</em>:2199) at <em>com</em>.<em>mysql</em>.<em>jdbc</em>.ConnectionImpl.connectOneTryOnly(ConnectionImpl.<em>java</em>:2230) at <em>com</em>.<em>mysql</em>.<em>jdbc</em>.ConnectionImpl.createNewIO(ConnectionImpl.<em>java</em>:2025) at <em>com</em>.<em>mysql</em>.<em>jdbc</em>.ConnectionImpl.(ConnectionImpl.<em>java</em>:778) at <em>com</em>.<em>mysql</em>.<em>jdbc</em>.JDBC4Connection.(JDBC4Connection.<em>java</em>:47) at <em>java</em>.base/jdk.internal.reflect.NativeConstructorAccessorImpl.newInstance0(Native Method) at <em>java</em>.base/jdk.internal.reflect.NativeConstructorAccessorImpl.newInstance(NativeConstructorAccessorImpl.<em>java</em>:62) at <em>java</em>.base/jdk.internal.reflect.DelegatingConstructorAccessorImpl.newInstance(DelegatingConstructorAccessorImpl.<em>java</em>:45) at <em>java</em>.base/<em>java</em>.<em>lang</em>.reflect.Constructor.newInstanceWithCaller(Constructor.<em>java</em>:500) at <em>java</em>.base/<em>java</em>.<em>lang</em>.reflect.Constructor.newInstance(Constructor.<em>java</em>:481) at <em>com</em>.<em>mysql</em>.<em>jdbc</em>.Util.handleNewInstance(Util.<em>java</em>:425) at <em>com</em>.<em>mysql</em>.<em>jdbc</em>.ConnectionImpl.getInstance(ConnectionImpl.<em>java</em>:386) at <em>com</em>.<em>mysql</em>.<em>jdbc</em>.NonRegistering<em>Driver</em>.connect(NonRegistering<em>Driver</em>.<em>java</em>:330) at <em>com</em>.mchange.v2.c3p0.<em>Driver</em>ManagerDataSource.getConnection(<em>Driver</em>ManagerDataSource.<em>java</em>:134) at <em>com</em>.mchange.v2.c3p0.WrapperConnectionPoolDataSource.getPooledConnection(WrapperConnectionPoolDataSource.<em>java</em>:182) at <em>com</em>.mchange.v2.c3p0.WrapperConnectionPoolDataSource.getPooledConnection(WrapperConnectionPoolDataSource.<em>java</em>:171) at <em>com</em>.mchange.v2.c3p0.impl.C3P0PooledConnectionPool$1PooledConnectionResourcePoolManager.acquireResource(C3P0PooledConnectionPool.<em>java</em>:137) at <em>com</em>.mchange.v2.resourcepool.BasicResourcePool.doAcquire(BasicResourcePool.<em>java</em>:1014) at <em>com</em>.mchange.v2.resourcepool.BasicResourcePool.access$800(BasicResourcePool.<em>java</em>:32) at <em>com</em>.mchange.v2.resourcepool.BasicResourcePool$AcquireTask.run(BasicResourcePool.<em>java</em>:1810) at <em>com</em>.mchange.v2.async.ThreadPoolAsynchronousRunner$PoolThread.run(ThreadPoolAsynchronousRunner.<em>java</em>:547) 8月 02, 2019 11:30:40 下午 <em>com</em>.mchange.v2.c3p0.<em>Driver</em>ManagerDataSource ensure<em>Driver</em>Loaded 警告: Could not load driverClass <em>com</em>.<em>mysql</em>.jbdc.<em>Driver</em> <em>java</em>.<em>lang</em>.<em>ClassNotFoundException</em>: <em>com</em>.<em>mysql</em>.jbdc.<em>Driver</em> at <em>java</em>.base/jdk.internal.loader.BuiltinClassLoader.loadClass(BuiltinClassLoader.<em>java</em>:583) at <em>java</em>.base/jdk.internal.loader.ClassLoaders$AppClassLoader.loadClass(ClassLoaders.<em>java</em>:178) at <em>java</em>.base/<em>java</em>.<em>lang</em>.ClassLoader.loadClass(ClassLoader.<em>java</em>:521) at <em>java</em>.base/<em>java</em>.<em>lang</em>.Class.forName0(Native Method) at <em>java</em>.base/<em>java</em>.<em>lang</em>.Class.forName(Class.<em>java</em>:332) at <em>com</em>.mchange.v2.c3p0.<em>Driver</em>ManagerDataSource.ensure<em>Driver</em>Loaded(<em>Driver</em>ManagerDataSource.<em>java</em>:100) at <em>com</em>.mchange.v2.c3p0.<em>Driver</em>ManagerDataSource.getConnection(<em>Driver</em>ManagerDataSource.<em>java</em>:132) at <em>com</em>.mchange.v2.c3p0.WrapperConnectionPoolDataSource.getPooledConnection(WrapperConnectionPoolDataSource.<em>java</em>:182) at <em>com</em>.mchange.v2.c3p0.WrapperConnectionPoolDataSource.getPooledConnection(WrapperConnectionPoolDataSource.<em>java</em>:171) at <em>com</em>.mchange.v2.c3p0.impl.C3P0PooledConnectionPool$1PooledConnectionResourcePoolManager.acquireResource(C3P0PooledConnectionPool.<em>java</em>:137) at <em>com</em>.mchange.v2.resourcepool.BasicResourcePool.doAcquire(BasicResourcePool.<em>java</em>:1014) at <em>com</em>.mchange.v2.resourcepool.BasicResourcePool.access$800(BasicResourcePool.<em>java</em>:32) at <em>com</em>.mchange.v2.resourcepool.BasicResourcePool$AcquireTask.run(BasicResourcePool.<em>java</em>:1810) at <em>com</em>.mchange.v2.async.ThreadPoolAsynchronousRunner$PoolThread.run(ThreadPoolAsynchronousRunner.<em>java</em>:547) 8月 02, 2019 11:30:40 下午 <em>com</em>.mchange.v2.c3p0.<em>Driver</em>ManagerDataSource ensure<em>Driver</em>Loaded 警告: Could not load driverClass <em>com</em>.<em>mysql</em>.jbdc.<em>Driver</em> <em>java</em>.<em>lang</em>.<em>ClassNotFoundException</em>: <em>com</em>.<em>mysql</em>.jbdc.<em>Driver</em> at <em>java</em>.base/jdk.internal.loader.BuiltinClassLoader.loadClass(BuiltinClassLoader.<em>java</em>:583) at <em>java</em>.base/jdk.internal.loader.ClassLoaders$AppClassLoader.loadClass(ClassLoaders.<em>java</em>:178) at <em>java</em>.base/<em>java</em>.<em>lang</em>.ClassLoader.loadClass(ClassLoader.<em>java</em>:521) at <em>java</em>.base/<em>java</em>.<em>lang</em>.Class.forName0(Native Method) at <em>java</em>.base/<em>java</em>.<em>lang</em>.Class.forName(Class.<em>java</em>:332) at <em>com</em>.mchange.v2.c3p0.<em>Driver</em>ManagerDataSource.ensure<em>Driver</em>Loaded(<em>Driver</em>ManagerDataSource.<em>java</em>:100) at <em>com</em>.mchange.v2.c3p0.<em>Driver</em>ManagerDataSource.getConnection(<em>Driver</em>ManagerDataSource.<em>java</em>:132) at <em>com</em>.mchange.v2.c3p0.WrapperConnectionPoolDataSource.getPooledConnection(WrapperConnectionPoolDataSource.<em>java</em>:182) at <em>com</em>.mchange.v2.c3p0.WrapperConnectionPoolDataSource.getPooledConnection(WrapperConnectionPoolDataSource.<em>java</em>:171) at <em>com</em>.mchange.v2.c3p0.impl.C3P0PooledConnectionPool$1PooledConnectionResourcePoolManager.acquireResource(C3P0PooledConnectionPool.<em>java</em>:137) at <em>com</em>.mchange.v2.resourcepool.BasicResourcePool.doAcquire(BasicResourcePool.<em>java</em>:1014) at <em>com</em>.mchange.v2.resourcepool.BasicResourcePool.access$800(BasicResourcePool.<em>java</em>:32) at <em>com</em>.mchange.v2.resourcepool.BasicResourcePool$AcquireTask.run(BasicResourcePool.<em>java</em>:1810) at <em>com</em>.mchange.v2.async.ThreadPoolAsynchronousRunner$PoolThread.run(ThreadPoolAsynchronousRunner.<em>java</em>:547) ```

Cause: java.lang.ClassNotFoundException:Cannot find class:com.mysql.cj.jdbc.Driver

使用IDEA 的maven项目,实现mybatis的入门案例 mybatis的主配置文件 &lt;?xml version="1.0" encoding="UTF-8"?&gt; &lt;!DOCTYPE configuration PUBLIC "-//mybatis.org//DTD Config 3.0//EN" "http://mybatis.org/dtd...

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昨天写了一个Swing小程序,运行的时候

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java.lang.ClassNotFoundException: com.mysql.cj.jdbc.Driver

参考 https://blog.csdn.net/weixin_42585871/article/details/88374879 <em>com</em>.<em>mysql</em>.cj.<em>jdbc</em>.<em>Driver</em>中的cj去掉就好了

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-

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