您好我正在使用C3P0连接池，我得到这个间歇性的错误：
java.sql.SQLException: No suitable driver found for jdbc:mysql://localhost/circuit
at java.sql.DriverManager.getConnection(Unknown Source)
at java.sql.DriverManager.getConnection(Unknown Source)
at com.mchange.v2.c3p0.DriverManagerDataSource.getConnection(DriverManagerDataSource.java:66)
at com.mchange.v2.c3p0.WrapperConnectionPoolDataSource.getPooledConnection(WrapperConnectionPoolDataSource.java:76)
at com.mchange.v2.c3p0.impl.C3P0PooledConnectionPool$1.acquireResource(C3P0PooledConnectionPool.java:66)
at com.mchange.v2.resourcepool.BasicResourcePool.assimilateResource(BasicResourcePool.java:787)
at com.mchange.v2.resourcepool.BasicResourcePool.acquireUntil(BasicResourcePool.java:548)
at com.mchange.v2.resourcepool.BasicResourcePool.access$000(BasicResourcePool.java:35)
at com.mchange.v2.resourcepool.BasicResourcePool$AcquireTask.run(BasicResourcePool.java:972)
at com.mchange.v2.async.ThreadPoolAsynchronousRunner$PoolThread.run(ThreadPoolAsynchronousRunner.java:148)
任何线索？