c3p0连接错误Anattemptbyaclienttocheckouta...

c3p0连接错误Anattemptbyaclienttocheckouta...
c3p0作为连接池，报：java.sql.SQLException: An attempt by a client to checkout a Connection has timed out.
网上查了很久，有人说是checkoutTimeout太短的原因，（Default: 0）于是由原来的1000改为2000,问题还是未解决。

然后找了份没有问题的配置作了些对比，发现我的maxPoolSize ＝100显得有些大，于是改为默认的15.再测试，居然没有问题了。

后来再试了大一点的60,也没有问题。

下面是我的配置：
Xml代码
1.<bean id="dataSource"
2.class="boPooledDataSource"
3.destroy-method="close">
4.<property name="driverClass" value="com.mysql.jdbc.Dr iver" />
5.<property name="jdbcUrl"
6.value="jdbc:mysql://localhost:3306/gjp" />
7.<property name="user" value="root" />
8.<property name="password" value="gjpgjp" />
9.<property name="initialPoolSize" value="20" />
10.<property name="minPoolSize" value="10" />
11.<property name="maxPoolSize" value="60" />
12.<property name="maxIdleTime" value="7200" />
13.<property name="idleConnectionTestPeriod" value=" 360" />
14.<property name="preferredTestQuery" value="select 1" />
15.<property name="acquireIncrement" value="5" />
16.<property name="acquireRetryAttempts" value="50"
/>
17.<property name="acquireRetryDelay" value="1000" / >
18.<property name="breakAfterAcquireFailure" value="tr ue" />
19.<property name="checkoutTimeout" value="20000" / >
20.<property name="autoCommitOnClose" value="false" />
21.<property name="forceIgnoreUnresolvedTransactions " value="false" />
22.<property name="unreturnedConnectionTimeout" val ue="1000" />
23.<property name="maxStatements" value="0" />
24.<property name="maxStatementsPerConnection" valu e="0" />
25.<property name="testConnectionOnCheckin" value=" true" />
26.<property name="testConnectionOnCheckout" value ="false" />
27.<property name="usesTraditionalReflectiveProxies" va lue="false" />
28.<property name="numHelperThreads" value="5" />
29.</bean>。