Java.sql.SQLException:Connections could not being acquired from the underlying database!

Warning: [Email protected]72--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 at tempts (30).
Java.sql.SQLException:Connections could not being acquired from the underlying database!
At Com.mchange.v2.sql.SqlUtils.toSQLException (sqlutils.java:104)
At Com.mchange.v2.c3p0.impl.C3P0PooledConnectionPool.checkoutPooledConnection (c3p0pooledconnectionpool.java:236 )
At Com.mchange.v2.c3p0.PoolBackedDataSource.getConnection (poolbackeddatasource.java:94)
At Com.mchange.v2.c3p0.ComboPooledDataSource.getConnection (combopooleddatasource.java:521)
At Org.apache.commons.dbutils.QueryRunner.prepareConnection (queryrunner.java:337)
At Org.apache.commons.dbutils.QueryRunner.update (queryrunner.java:652)
At Com.imooc.dao.impl.UserDaoImpl.regist (userdaoimpl.java:27)
At Com.imooc.service.impl.UserServiceImpl.regist (userserviceimpl.java:19)
At Com.imooc.servlet.RegistServlet.doGet (registservlet.java:43)
At Com.imooc.servlet.RegistServlet.doPost (registservlet.java:55)
At Javax.servlet.http.HttpServlet.service (httpservlet.java:648)
At Javax.servlet.http.HttpServlet.service (httpservlet.java:729)
At Org.apache.catalina.core.ApplicationFilterChain.internalDoFilter (applicationfilterchain.java:292)
At Org.apache.catalina.core.ApplicationFilterChain.doFilter (applicationfilterchain.java:207)
At Org.apache.tomcat.websocket.server.WsFilter.doFilter (wsfilter.java:52)
At Org.apache.catalina.core.ApplicationFilterChain.internalDoFilter (applicationfilterchain.java:240)
At Org.apache.catalina.core.ApplicationFilterChain.doFilter (applicationfilterchain.java:207)
At Org.apache.catalina.core.StandardWrapperValve.invoke (standardwrappervalve.java:212)
At Org.apache.catalina.core.StandardContextValve.invoke (standardcontextvalve.java:106)
At Org.apache.catalina.authenticator.AuthenticatorBase.invoke (authenticatorbase.java:502)
At Org.apache.catalina.core.StandardHostValve.invoke (standardhostvalve.java:141)
At Org.apache.catalina.valves.ErrorReportValve.invoke (errorreportvalve.java:79)
At Org.apache.catalina.valves.AbstractAccessLogValve.invoke (abstractaccesslogvalve.java:616)
At Org.apache.catalina.core.StandardEngineValve.invoke (standardenginevalve.java:88)
At Org.apache.catalina.connector.CoyoteAdapter.service (coyoteadapter.java:528)
At Org.apache.coyote.http11.AbstractHttp11Processor.process (abstracthttp11processor.java:1099)
At Org.apache.coyote.abstractprotocol$abstractconnectionhandler.process (abstractprotocol.java:670)
At Org.apache.tomcat.util.net.nioendpoint$socketprocessor.dorun (nioendpoint.java:1520)
At Org.apache.tomcat.util.net.nioendpoint$socketprocessor.run (nioendpoint.java:1476)
At Java.util.concurrent.ThreadPoolExecutor.runWorker (threadpoolexecutor.java:1142)
At Java.util.concurrent.threadpoolexecutor$worker.run (threadpoolexecutor.java:617)
At Org.apache.tomcat.util.threads.taskthread$wrappingrunnable.run (taskthread.java:61)
At Java.lang.Thread.run (thread.java:745)
caused By:com.mchange.v2.resourcepool.cannotacquireresourceexception:a Resourcepool could not acquire A resource From its primary factory or source.
At Com.mchange.v2.resourcepool.BasicResourcePool.awaitAcquire (basicresourcepool.java:970)
At Com.mchange.v2.resourcepool.BasicResourcePool.checkoutResource (basicresourcepool.java:208)
At Com.mchange.v2.c3p0.impl.C3P0PooledConnectionPool.checkoutPooledConnection (c3p0pooledconnectionpool.java:232 )
... More
March 18, 2017 10:17:38 pm Com.mchange.v2.resourcepool.basicresourcepool$acquiretask Run
Warning: [Email protected]c--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 at tempts (30).

Personal solutions:

Change other versions of the C3P0 jar package

C3p0-0.9.1.2.jar Address

Portal

Http://pan.baidu.com/s/1qYpqDVQ

Java.sql.SQLException:Connections could not being acquired from the underlying database!