数据库连接失败

c3p0-config.xml

<?xml version="1.0" encoding="UTF-8"?>
<c3p0-config>
   <named-config name="localhost">
       <property name="driverClass">com.mysql.jdbc.Driver</property>
       <property name="jdbcUrl">jdbc:mysql://localhost:3306/regist_web</property>
       <property name="user">root</property>
       <property name="password">123456</property>
       <!-- 初始化时一个连接池尝试获得的连接数量，默认是3，大小应该在maxPoolSize和minPoolSize之间 -->
       <property name="initialPoolSize">5</property>
       <!-- 一个连接最大空闲时间(单位是秒)，0意味着连接不会过时 -->
       <property name="maxIdleTime">30</property>
       <!-- 任何指定时间的最大连接数量 ,默认值是15 -->
       <property name="maxPoolSize">20</property>
       <!-- 任何指定时间的最小连接数量 ,默认值是3 -->
       <property name="minPoolSize">5</property>
   </named-config>
</c3p0-config>

错误信息

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:119)

at com.mchange.v2.c3p0.WrapperConnectionPoolDataSource.getPooledConnection(WrapperConnectionPoolDataSource.java:143)

at com.mchange.v2.c3p0.WrapperConnectionPoolDataSource.getPooledConnection(WrapperConnectionPoolDataSource.java:132)

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)

06-Jul-2017 15:53:51.824 警告 [com.mchange.v2.async.ThreadPoolAsynchronousRunner$PoolThread-#0] com.mchange.v2.resourcepool.BasicResourcePool$AcquireTask.run com.mchange.v2.resourcepool.BasicResourcePool$AcquireTask@1b054d9c -- 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:119)

at com.mchange.v2.c3p0.WrapperConnectionPoolDataSource.getPooledConnection(WrapperConnectionPoolDataSource.java:143)

at com.mchange.v2.c3p0.WrapperConnectionPoolDataSource.getPooledConnection(WrapperConnectionPoolDataSource.java:132)

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 org.apache.commons.dbutils.QueryRunner.prepareConnection(QueryRunner.java:337)

at org.apache.commons.dbutils.QueryRunner.update(QueryRunner.java:652)

at cq.my.dao.impl.UserDaoImpl.regist(UserDaoImpl.java:30)

at cq.my.service.impl.UserServiceImpl.regist(UserServiceImpl.java:21)

at cq.my.servlet.RegistServlet.doPost(RegistServlet.java:72)

at javax.servlet.http.HttpServlet.service(HttpServlet.java:661)

at javax.servlet.http.HttpServlet.service(HttpServlet.java:742)

at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:231)

at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:166)

at org.apache.tomcat.websocket.server.WsFilter.doFilter(WsFilter.java:53)

at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:193)

at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:166)

at org.apache.catalina.core.StandardWrapperValve.invoke(StandardWrapperValve.java:199)

at org.apache.catalina.core.StandardContextValve.invoke(StandardContextValve.java:96)

at org.apache.catalina.authenticator.AuthenticatorBase.invoke(AuthenticatorBase.java:475)

at org.apache.catalina.core.StandardHostValve.invoke(StandardHostValve.java:140)

at org.apache.catalina.valves.ErrorReportValve.invoke(ErrorReportValve.java:80)

at org.apache.catalina.valves.AbstractAccessLogValve.invoke(AbstractAccessLogValve.java:624)

at org.apache.catalina.core.StandardEngineValve.invoke(StandardEngineValve.java:87)

at org.apache.catalina.connector.CoyoteAdapter.service(CoyoteAdapter.java:342)

at org.apache.coyote.http11.Http11Processor.service(Http11Processor.java:498)

at org.apache.coyote.AbstractProcessorLight.process(AbstractProcessorLight.java:66)

at org.apache.coyote.AbstractProtocol$ConnectionHandler.process(AbstractProtocol.java:796)

at org.apache.tomcat.util.net.NioEndpoint$SocketProcessor.doRun(NioEndpoint.java:1366)

at org.apache.tomcat.util.net.SocketProcessorBase.run(SocketProcessorBase.java:49)

at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1142)

at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:617)

at org.apache.tomcat.util.threads.TaskThread$WrappingRunnable.run(TaskThread.java:61)

at java.lang.Thread.run(Thread.java:745)

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)

... 30 more

06-Jul-2017 15:53:51.824 警告 [com.mchange.v2.async.ThreadPoolAsynchronousRunner$PoolThread-#2] com.mchange.v2.resourcepool.BasicResourcePool$AcquireTask.run com.mchange.v2.resourcepool.BasicResourcePool$AcquireTask@6d8849c0 -- 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:119)

at com.mchange.v2.c3p0.WrapperConnectionPoolDataSource.getPooledConnection(WrapperConnectionPoolDataSource.java:143)

at com.mchange.v2.c3p0.WrapperConnectionPoolDataSource.getPooledConnection(WrapperConnectionPoolDataSource.java:132)

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)