C3P0进行query查询时连接超时

Question

在使用C3P0连接池写Javaweb项目时遇到这样的问题：可以登录、进行一些操作（应该是已经连上数据库了）但是只要进行query查询时就会这样的报错
java.sql.SQLException: An attempt by a client to checkout a Connection has timed out.
at com.mchange.v2.sql.SqlUtils.toSQLException(SqlUtils.java:118)
at com.mchange.v2.sql.SqlUtils.toSQLException(SqlUtils.java:77)
at com.mchange.v2.c3p0.impl.C3P0PooledConnectionPool.checkoutPooledConnection(C3P0PooledConnectionPool.java:690)
at com.mchange.v2.c3p0.impl.AbstractPoolBackedDataSource.getConnection(AbstractPoolBackedDataSource.java:140)
at org.apache.commons.dbutils.AbstractQueryRunner.prepareConnection(AbstractQueryRunner.java:319)
at org.apache.commons.dbutils.QueryRunner.query(QueryRunner.java:345)

Answer 1

参考检查一下你的 jdbc驱动 和 mysql版本：

An attempt by a client to checkout a Connection has timed out._王嘻嘻Bella的博客-CSDN博客 Exception in thread “main” java.sql.SQLException: An attempt by a client to checkout a Connection has timed out.at com.mchange.v2.sql.SqlUtils.toSQLException(SqlUtils.java:118)at com.mchange.v2.sql.SqlUtils.toSQLException(SqlUtils.java:77)at com.mchange https://blog.csdn.net/m0_46648272/article/details/120186958

SQLException: An attempt by a client to checkout a Connection has timed out - 简书 在测试黑马JavaWeb连接池成C3P0时报错:java.sql.SQLException: An attempt by a client to checkout a Con... https://www.jianshu.com/p/27e9d5675d06