实施例::

Question

这是chandrashekhar，

当我一次发布多个请求（100）时，它会创建c3p0实例。

实施例::

 [AbstractPoolBackedDataSource] Initializing c3p0 pool...
 com.mchange.v2.c3p0.PoolBackedDataSource@3b9421d5 [ connectionPoolDataSource -> com.mchange.v2.c3p0.WrapperConnectionPoolDataSource@8f5cd4d1 [ acquireIncrement -> 5, acquireRetryAttempts -> 30, acquireRetryDelay -> 1000, autoCommitOnClose -> true, automaticTestTable -> null, breakAfterAcquireFailure -> false, checkoutTimeout -> 0, connectionCustomizerClassName -> null, connectionTesterClassName -> com.mchange.v2.c3p0.impl.DefaultConnectionTester, debugUnreturnedConnectionStackTraces -> true, factoryClassLocation -> null, forceIgnoreUnresolvedTransactions -> false, identityToken -> 1hge2v08pob8zy1nl2rit|1474b36, idleConnectionTestPeriod -> 3600, initialPoolSize -> 10, maxAdministrativeTaskTime -> 600, maxConnectionAge -> 0, maxIdleTime -> 18000, maxIdleTimeExcessConnections -> 0, maxPoolSize -> 50, maxStatements -> 0, maxStatementsPerConnection -> 0, minPoolSize -> 10, nestedDataSource -> com.mchange.v2.c3p0.DriverManagerDataSource@3a7ecbf6 [ description -> null, driverClass -> null, factoryClassLocation -> null, identityToken -> 1hge2v08pob8zy1nl2rit|87f988, jdbcUrl -> jdbc:mysql://localhost:3306/tiscover, properties -> {user=******, password=******} ], preferredTestQuery -> null, propertyCycle -> 0, testConnectionOnCheckin -> false, testConnectionOnCheckout -> false, unreturnedConnectionTimeout -> 600, usesTraditionalReflectiveProxies -> false; userOverrides: {} ], dataSourceName -> null, factoryClassLocation -> null, identityToken -> 1hge2v08pob8zy1nl2rit|6c2668, numHelperThreads -> 10 ]
13:24:16,003 INFO  [AbstractPoolBackedDataSource]
 Initializing c3p0 pool... com.mchange.v2.c3p0.PoolBackedDataSource@38d1c65b [ connectionPoolDataSource -> com.mchange.v2.c3p0.WrapperConnectionPoolDataSource@efa9b134 [ acquireIncrement -> 5, acquireRetryAttempts -> 30, acquireRetryDelay -> 1000, autoCommitOnClose -> true, automaticTestTable -> null, breakAfterAcquireFailure -> false, checkoutTimeout -> 0, connectionCustomizerClassName -> null, connectionTesterClassName -> com.mchange.v2.c3p0.impl.DefaultConnectionTester, debugUnreturnedConnectionStackTraces -> true, factoryClassLocation -> null, forceIgnoreUnresolvedTransactions -> false, identityToken -> 1hge2v08pob8zy1nl2rit|d46725, idleConnectionTestPeriod -> 3600, initialPoolSize -> 10, maxAdministrativeTaskTime -> 600, maxConnectionAge -> 0, maxIdleTime -> 18000, maxIdleTimeExcessConnections -> 0, maxPoolSize -> 50, maxStatements -> 0, maxStatementsPerConnection -> 0, minPoolSize -> 10, nestedDataSource -> com.mchange.v2.c3p0.DriverManagerDataSource@f3230993 [ description -> null, driverClass -> null, factoryClassLocation -> null, identityToken -> 1hge2v08pob8zy1nl2rit|b31fb1, jdbcUrl -> jdbc:mysql://localhost:3306/tiscover, properties -> {user=******, password=******} ], preferredTestQuery -> null, propertyCycle -> 0, testConnectionOnCheckin -> false, testConnectionOnCheckout -> false, unreturnedConnectionTimeout -> 600, usesTraditionalReflectiveProxies -> false; userOverrides: {} ], dataSourceName -> null, factoryClassLocation -> null, identityToken -> 1hge2v08pob8zy1nl2rit|9861d7, numHelperThreads -> 10 ]
13:24:16,004 INFO  [AbstractPoolBackedDataSource] 
Initializing c3p0 pool... com.mchange.v2.c3p0.PoolBackedDataSource@3b6dc297 [ connectionPoolDataSource -> com.mchange.v2.c3p0.WrapperConnectionPoolDataSource@433920d4 [ acquireIncrement -> 5, acquireRetryAttempts -> 30, acquireRetryDelay -> 1000, autoCommitOnClose -> true, automaticTestTable -> null, breakAfterAcquireFailure -> false, checkoutTimeout -> 0, connectionCustomizerClassName -> null, connectionTesterClassName -> com.mchange.v2.c3p0.impl.DefaultConnectionTester, debugUnreturnedConnectionStackTraces -> true, factoryClassLocation -> null, forceIgnoreUnresolvedTransactions -> false, identityToken -> 1hge2v08pob8zy1nl2rit|3561b9, idleConnectionTestPeriod -> 3600, initialPoolSize -> 10, maxAdministrativeTaskTime -> 600, maxConnectionAge -> 0, maxIdleTime -> 18000, maxIdleTimeExcessConnections -> 0, maxPoolSize -> 50, maxStatements -> 0, maxStatementsPerConnection -> 0, minPoolSize -> 10, nestedDataSource -> com.mchange.v2.c3p0.DriverManagerDataSource@4084843c [ description -> null, driverClass -> null, factoryClassLocation -> null, identityToken -> 1hge2v08pob8zy1nl2rit|3f9de3, jdbcUrl -> jdbc:mysql://localhost:3306/tiscover, properties -> {user=******, password=******} ], preferredTestQuery -> null, propertyCycle -> 0, testConnectionOnCheckin -> false, testConnectionOnCheckout -> false, unreturnedConnectionTimeout -> 600, usesTraditionalReflectiveProxies -> false; userOverrides: {} ], dataSourceName -> null, factoryClassLocation -> null, identityToken -> 1hge2v08pob8zy1nl2rit|6dfb07, numHelperThreads -> 10 ]
13:24:16,004 INFO  [AbstractPoolBackedDataSource] 
Initializing c3p0 pool... com.mchange.v2.c3p0.PoolBackedDataSource@3bcf7210 [ connectionPoolDataSource -> com.mchange.v2.c3p0.WrapperConnectionPoolDataSource@896b85d4 [ acquireIncrement -> 5, acquireRetryAttempts -> 30, acquireRetryDelay -> 1000, autoCommitOnClose -> true, automaticTestTable -> null, breakAfterAcquireFailure -> false, checkoutTimeout -> 0, connectionCustomizerClassName -> null, connectionTesterClassName -> com.mchange.v2.c3p0.impl.DefaultConnectionTester, debugUnreturnedConnectionStackTraces -> true, factoryClassLocation -> null, forceIgnoreUnresolvedTransactions -> false, identityToken -> 1hge2v08pob8zy1nl2rit|16e47cb, idleConnectionTestPeriod -> 3600, initialPoolSize -> 10, maxAdministrativeTaskTime -> 600, maxConnectionAge -> 0, maxIdleTime -> 18000, maxIdleTimeExcessConnections -> 0, maxPoolSize -> 50, maxStatements -> 0, maxStatementsPerConnection -> 0, minPoolSize -> 10, nestedDataSource -> com.mchange.v2.c3p0.DriverManagerDataSource@f06dd726 [ description -> null, driverClass -> null, factoryClassLocation -> null, identityToken -> 1hge2v08pob8zy1nl2rit|bd7db5, jdbcUrl -> jdbc:mysql://localhost:3306/tiscover, properties -> {user=******, password=******} ], preferredTestQuery -> null, propertyCycle -> 0, testConnectionOnCheckin -> false, testConnectionOnCheckout -> false, unreturnedConnectionTimeout -> 600, usesTraditionalReflectiveProxies -> false; userOverrides: {} ], dataSourceName -> null, factoryClassLocation -> null, identityToken -> 1hge2v08pob8zy1nl2rit|1e616dc, numHelperThreads -> 10 ]
13:24:16,006 INFO  [AbstractPoolBackedDataSource]

....等100次。

这背后的意义是什么，是100个连接池实例创建..？是c3p0连接池是不是线程安全..？如果是这样我们如何处理......？

请任何人帮助我。

提前谢谢，钱德拉希克哈

Answer 1

首先，连接只能在一次与数据库交互时运行。如果您跨多个线程共享连接，则行为将是随机的。理想情况下，当您想要与DB交互时，只需运行一些INSERT / UPDATE / DELETE语句并获取更新计数或运行SELECT语句并读取结果集然后关闭所有资源（即viz）。结果集，陈述和连接）。

如果连接来自连接池，那么pooler会处理此类连接上的close（）调用，以将连接返回池中。

您打印的语句是来自pooler的有关创建的连接池的INFO。

是c3p0连接池线程安全与否..？

实施例::

1 个答案: