問題：我的目標是訪問遠程數據庫，操作遠程數據庫?，F在我使用了C3P0數據源，是可以訪問本地數據庫，可以早增刪改查等操作。但我將數據庫換為服務器上的數據庫的時候，報APPARENT DEADLOCK問題，有朋友知道怎么解決這個問題嗎？ 嘗試 我自己首先搜索答案C3P0錯誤APPARENT DEADLOCK!!!解決 ，添加maxStatements和maxStatementsPerConnection到我的配置文件中再次嘗試，還是不行。 然后又搜索了c3p0 APPARENT DEADLOCK!!! 錯誤參考 ，里面也是說把maxStatements設置為0其他的解決方法也不大行。 我出現的異常 十二月 07, 2016 9:30:43 下午 com.mchange.v2.log.MLog <clinit> 信息: MLog clients using java 1.4+ standard logging. 十二月 07, 2016 9:30:43 下午 com.mchange.v2.c3p0.C3P0Registry banner 信息: Initializing c3p0-0.9.1.2 [built 21-May-2007 15:04:56; debug? true; trace: 10] 十二月 07, 2016 9:30:43 下午 com.mchange.v2.c3p0.impl.AbstractPoolBackedDataSource getPoolManager 信息: Initializing c3p0 pool... com.mchange.v2.c3p0.ComboPooledDataSource [ acquireIncrement -> 3, acquireRetryAttempt s -> 30, acquireRetryDelay -> 1000, autoCommitOnClose -> false, automaticTestTable -> null, breakAfterAcquireFailure -> false, checkoutTimeout -> 0, connectionCustomizerClassName -> null, connectionTesterClassName -> com.mchange.v2. c3p0.impl.DefaultConnectionTester, dataSourceName -> 1bqvvjb9k1occ65kc53q2e|f7df584, debugUnreturnedConnectionStackT races -> false, description -> null, driverClass -> com.mysql.jdbc.Driver, factoryClassLocation -> null, forceIgnore UnresolvedTransactions -> false, identityToken -> 1bqvvjb9k1occ65kc53q2e|f7df584, idleConnectionTestPeriod -> 0, ini tialPoolSize -> 5, jdbcUrl -> jdbc:mysql://123.206.16.183:3306/dbWaterColInfo, maxAdministrativeTaskTime -> 0, maxCo nnectionAge -> 0, maxIdleTime -> 30, maxIdleTimeExcessConnections -> 0, maxPoolSize -> 20, maxStatements -> 0, maxSt atementsPerConnection -> 100, minPoolSize -> 5, numHelperThreads -> 3, numThreadsAwaitingCheckoutDefaultUser -> 0, p referredTestQuery -> null, properties -> {user=******, password=******}, propertyCycle -> 0, testConnectionOnCheckin -> false, testConnectionOnCheckout -> false, unreturnedConnectionTimeout -> 0, usesTraditionalReflectiveProxies -> false ] 十二月 07, 2016 9:31:03 下午 com.mchange.v2.async.ThreadPoolAsynchronousRunner$DeadlockDetector run 警告: com.mchange.v2.async.ThreadPoolAsynchronousRunner$DeadlockDetector@55a54ea0 -- APPARENT DEADLOCK!!! Creating eme rgency threads for unassigned pending tasks! 十二月 07, 2016 9:31:03 下午 com.mchange.v2.async.ThreadPoolAsynchronousRunner$DeadlockDetector run 警告: com.mchange.v2.async.ThreadPoolAsynchronousRunner$DeadlockDetector@55a54ea0 -- APPARENT DEADLOCK!!! Complete Sta tus: Managed Threads: 3 Active Threads: 3 Active Tasks: com.mchange.v2.resourcepool.BasicResourcePool$AcquireTask@304cf82d (com.mchange.v2.async.ThreadPoolAsynchronousRun ner$PoolThread-#1) com.mchange.v2.resourcepool.BasicResourcePool$AcquireTask@d396b21 (com.mchange.v2.async.ThreadPoolAsynchronousRunn er$PoolThread-#2) com.mchange.v2.resourcepool.BasicResourcePool$AcquireTask@34a84a4f (com.mchange.v2.async.ThreadPoolAsynchronousRun ner$PoolThread-#0) Pending Tasks: com.mchange.v2.resourcepool.BasicResourcePool$AcquireTask@14a6a38b com.mchange.v2.resourcepool.BasicResourcePool$AcquireTask@483b0544 Pool thread stack traces: Thread[com.mchange.v2.async.ThreadPoolAsynchronousRunner$PoolThread-#1,5,main] java.lang.Thread.sleep(Native Method) com.mchange.v2.resourcepool.BasicResourcePool$AcquireTask.run(BasicResourcePool.java:1805) com.mchange.v2.async.ThreadPoolAsynchronousRunner$PoolThread.run(ThreadPoolAsynchronousRunner.java:547) Thread[com.mchange.v2.async.ThreadPoolAsynchronousRunner$PoolThread-#2,5,main] java.lang.Thread.sleep(Native Method) com.mchange.v2.resourcepool.BasicResourcePool$AcquireTask.run(BasicResourcePool.java:1805) com.mchange.v2.async.ThreadPoolAsynchronousRunner$PoolThread.run(ThreadPoolAsynchronousRunner.java:547) Thread[com.mchange.v2.async.ThreadPoolAsynchronousRunner$PoolThread-#0,5,main] java.lang.Thread.sleep(Native Method) com.mchange.v2.resourcepool.BasicResourcePool$AcquireTask.run(BasicResourcePool.java:1805) com.mchange.v2.async.ThreadPoolAsynchronousRunner$PoolThread.run(ThreadPoolAsynchronousRunner.java:547) 十二月 07, 2016 9:31:12 下午 com.mchange.v2.resourcepool.BasicResourcePool$AcquireTask run 警告: com.mchange.v2.resourcepool.BasicResourcePool$AcquireTask@304cf82d -- Acquisition Attempt Failed!!! Clearing pen ding acquires. While trying to acquire a needed new resource, we failed to succeed more than the maximum number of a llowed acquisition attempts (30). Last acquisition attempt exception: com.mysql.jdbc.CommunicationsException: Communications link failure due to underlying exception: ** BEGIN NESTED EXCEPTION ** java.net.SocketException MESSAGE: Host is down STACKTRACE: java.net.SocketException: Host is down at java.net.PlainSocketImpl.socketConnect(Native Method) at java.net.AbstractPlainSocketImpl.doConnect(AbstractPlainSocketImpl.java:339) at java.net.AbstractPlainSocketImpl.connectToAddress(AbstractPlainSocketImpl.java:200) at java.net.AbstractPlainSocketImpl.connect(AbstractPlainSocketImpl.java:182) at java.net.SocksSocketImpl.connect(SocksSocketImpl.java:392) at java.net.Socket.connect(Socket.java:579) at java.net.Socket.connect(Socket.java:528) at java.net.Socket.<init>(Socket.java:425) at java.net.Socket.<init>(Socket.java:241) at com.mysql.jdbc.StandardSocketFactory.connect(StandardSocketFactory.java:256) at com.mysql.jdbc.MysqlIO.<init>(MysqlIO.java:271) at com.mysql.jdbc.Connection.createNewIO(Connection.java:2771) at com.mysql.jdbc.Connection.<init>(Connection.java:1555) at com.mysql.jdbc.NonRegisteringDriver.connect(NonRegisteringDriver.java:285) at com.mchange.v2.c3p0.DriverManagerDataSource.getConnection(DriverManagerDataSource.java:134) at com.mchange.v2.c3p0.WrapperConnectionPoolDataSource.getPooledConnection(WrapperConnectionPoolDataSource.java:182 ) at com.mchange.v2.c3p0.WrapperConnectionPoolDataSource.getPooledConnection(WrapperConnectionPoolDataSource.java:171 ) at com.mchange.v2.c3p0.impl.C3P0PooledConnectionPool$1PooledConnectionResourcePoolManager.acquireResource(C3P0Poole dConnectionPool.java:137) at com.mchange.v2.resourcepool.BasicResourcePool.doAcquire(BasicResourcePool.java:1014) at com.mchange.v2.resourcepool.BasicResourcePool.access$800(BasicResourcePool.java:32) at com.mchange.v2.resourcepool.BasicResourcePool$AcquireTask.run(BasicResourcePool.java:1810) at com.mchange.v2.async.ThreadPoolAsynchronousRunner$PoolThread.run(ThreadPoolAsynchronousRunner.java:547) ** END NESTED EXCEPTION ** Last packet sent to the server was 0 ms ago. at com.mysql.jdbc.Connection.createNewIO(Connection.java:2847) at com.mysql.jdbc.Connection.<init>(Connection.java:1555) at com.mysql.jdbc.NonRegisteringDriver.connect(NonRegisteringDriver.java:285) at com.mchange.v2.c3p0.DriverManagerDataSource.getConnection(DriverManagerDataSource.java:134) at com.mchange.v2.c3p0.WrapperConnectionPoolDataSource.getPooledConnection(WrapperConnectionPoolDataSource.java:182 ) at com.mchange.v2.c3p0.WrapperConnectionPoolDataSource.getPooledConnection(WrapperConnectionPoolDataSource.java:171 ) at com.mchange.v2.c3p0.impl.C3P0PooledConnectionPool$1PooledConnectionResourcePoolManager.acquireResource(C3P0Poole dConnectionPool.java:137) at com.mchange.v2.resourcepool.BasicResourcePool.doAcquire(BasicResourcePool.java:1014) at com.mchange.v2.resourcepool.BasicResourcePool.access$800(BasicResourcePool.java:32) at com.mchange.v2.resourcepool.BasicResourcePool$AcquireTask.run(BasicResourcePool.java:1810) at com.mchange.v2.async.ThreadPoolAsynchronousRunner$PoolThread.run(ThreadPoolAsynchronousRunner.java:547) 十二月 07, 2016 9:31:12 下午 com.mchange.v2.resourcepool.BasicResourcePool$AcquireTask run 警告: com.mchange.v2.resourcepool.BasicResourcePool$AcquireTask@34a84a4f -- Acquisition Attempt Failed!!! Clearing pen ding acquires. While trying to acquire a needed new resource, we failed to succeed more than the maximum number of a llowed acquisition attempts (30). Last acquisition attempt exception: com.mysql.jdbc.CommunicationsException: Communications link failure due to underlying exception: ** BEGIN NESTED EXCEPTION ** java.net.SocketException MESSAGE: Host is down STACKTRACE: java.net.SocketException: Host is down at java.net.PlainSocketImpl.socketConnect(Native Method) at java.net.AbstractPlainSocketImpl.doConnect(AbstractPlainSocketImpl.java:339) at java.net.AbstractPlainSocketImpl.connectToAddress(AbstractPlainSocketImpl.java:200) at java.net.AbstractPlainSocketImpl.connect(AbstractPlainSocketImpl.java:182) at java.net.SocksSocketImpl.connect(SocksSocketImpl.java:392) at java.net.Socket.connect(Socket.java:579) at java.net.Socket.connect(Socket.java:528) at java.net.Socket.<init>(Socket.java:425) at java.net.Socket.<init>(Socket.java:241) at com.mysql.jdbc.StandardSocketFactory.connect(StandardSocketFactory.java:256) at com.mysql.jdbc.MysqlIO.<init>(MysqlIO.java:271) at com.mysql.jdbc.Connection.createNewIO(Connection.java:2771) at com.mysql.jdbc.Connection.<init>(Connection.java:1555) at com.mysql.jdbc.NonRegisteringDriver.connect(NonRegisteringDriver.java:285) at com.mchange.v2.c3p0.DriverManagerDataSource.getConnection(DriverManagerDataSource.java:134) at com.mchange.v2.c3p0.WrapperConnectionPoolDataSource.getPooledConnection(WrapperConnectionPoolDataSource.java:182 ) at com.mchange.v2.c3p0.WrapperConnectionPoolDataSource.getPooledConnection(WrapperConnectionPoolDataSource.java:171 ) at com.mchange.v2.c3p0.impl.C3P0PooledConnectionPool$1PooledConnectionResourcePoolManager.acquireResource(C3P0Poole dConnectionPool.java:137) at com.mchange.v2.resourcepool.BasicResourcePool.doAcquire(BasicResourcePool.java:1014) at com.mchange.v2.resourcepool.BasicResourcePool.access$800(BasicResourcePool.java:32) at com.mchange.v2.resourcepool.BasicResourcePool$AcquireTask.run(BasicResourcePool.java:1810) at com.mchange.v2.async.ThreadPoolAsynchronousRunner$PoolThread.run(ThreadPoolAsynchronousRunner.java:547) ** END NESTED EXCEPTION ** Last packet sent to the server was 0 ms ago. at com.mysql.jdbc.Connection.createNewIO(Connection.java:2847) at com.mysql.jdbc.Connection.<init>(Connection.java:1555) at com.mysql.jdbc.NonRegisteringDriver.connect(NonRegisteringDriver.java:285) at com.mchange.v2.c3p0.DriverManagerDataSource.getConnection(DriverManagerDataSource.java:134) at com.mchange.v2.c3p0.WrapperConnectionPoolDataSource.getPooledConnection(WrapperConnectionPoolDataSource.java:182 ) at com.mchange.v2.c3p0.WrapperConnectionPoolDataSource.getPooledConnection(WrapperConnectionPoolDataSource.java:171 ) at com.mchange.v2.c3p0.impl.C3P0PooledConnectionPool$1PooledConnectionResourcePoolManager.acquireResource(C3P0Poole dConnectionPool.java:137) at com.mchange.v2.resourcepool.BasicResourcePool.doAcquire(BasicResourcePool.java:1014) at com.mchange.v2.resourcepool.BasicResourcePool.access$800(BasicResourcePool.java:32) at com.mchange.v2.resourcepool.BasicResourcePool$AcquireTask.run(BasicResourcePool.java:1810) at com.mchange.v2.async.ThreadPoolAsynchronousRunner$PoolThread.run(ThreadPoolAsynchronousRunner.java:547) 十二月 07, 2016 9:31:12 下午 com.mchange.v2.resourcepool.BasicResourcePool$AcquireTask run 警告: com.mchange.v2.resourcepool.BasicResourcePool$AcquireTask@d396b21 -- Acquisition Attempt Failed!!! Clearing pend ing acquires. While trying to acquire a needed new resource, we failed to succeed more than the maximum number of al lowed acquisition attempts (30). Last acquisition attempt exception: com.mysql.jdbc.CommunicationsException: Communications link failure due to underlying exception: ** BEGIN NESTED EXCEPTION ** java.net.SocketException MESSAGE: Host is down STACKTRACE: java.net.SocketException: Host is down at java.net.PlainSocketImpl.socketConnect(Native Method) at java.net.AbstractPlainSocketImpl.doConnect(AbstractPlainSocketImpl.java:339) at java.net.AbstractPlainSocketImpl.connectToAddress(AbstractPlainSocketImpl.java:200) at java.net.AbstractPlainSocketImpl.connect(AbstractPlainSocketImpl.java:182) at java.net.SocksSocketImpl.connect(SocksSocketImpl.java:392) at java.net.Socket.connect(Socket.java:579) at java.net.Socket.connect(Socket.java:528) at java.net.Socket.<init>(Socket.java:425) at java.net.Socket.<init>(Socket.java:241) at com.mysql.jdbc.StandardSocketFactory.connect(StandardSocketFactory.java:256) at com.mysql.jdbc.MysqlIO.<init>(MysqlIO.java:271) at com.mysql.jdbc.Connection.createNewIO(Connection.java:2771) at com.mysql.jdbc.Connection.<init>(Connection.java:1555) at com.mysql.jdbc.NonRegisteringDriver.connect(NonRegisteringDriver.java:285) at com.mchange.v2.c3p0.DriverManagerDataSource.getConnection(DriverManagerDataSource.java:134) at com.mchange.v2.c3p0.WrapperConnectionPoolDataSource.getPooledConnection(WrapperConnectionPoolDataSource.java:182 ) at com.mchange.v2.c3p0.WrapperConnectionPoolDataSource.getPooledConnection(WrapperConnectionPoolDataSource.java:171 ) at com.mchange.v2.c3p0.impl.C3P0PooledConnectionPool$1PooledConnectionResourcePoolManager.acquireResource(C3P0Poole dConnectionPool.java:137) at com.mchange.v2.resourcepool.BasicResourcePool.doAcquire(BasicResourcePool.java:1014) at com.mchange.v2.resourcepool.BasicResourcePool.access$800(BasicResourcePool.java:32) at com.mchange.v2.resourcepool.BasicResourcePool$AcquireTask.run(BasicResourcePool.java:1810) at com.mchange.v2.async.ThreadPoolAsynchronousRunner$PoolThread.run(ThreadPoolAsynchronousRunner.java:547) ** END NESTED EXCEPTION ** Last packet sent to the server was 1 ms ago. at com.mysql.jdbc.Connection.createNewIO(Connection.java:2847) at com.mysql.jdbc.Connection.<init>(Connection.java:1555) at com.mysql.jdbc.NonRegisteringDriver.connect(NonRegisteringDriver.java:285) at com.mchange.v2.c3p0.DriverManagerDataSource.getConnection(DriverManagerDataSource.java:134) at com.mchange.v2.c3p0.WrapperConnectionPoolDataSource.getPooledConnection(WrapperConnectionPoolDataSource.java:182 ) at com.mchange.v2.c3p0.WrapperConnectionPoolDataSource.getPooledConnection(WrapperConnectionPoolDataSource.java:171 ) at com.mchange.v2.c3p0.impl.C3P0PooledConnectionPool$1PooledConnectionResourcePoolManager.acquireResource(C3P0Poole dConnectionPool.java:137) at com.mchange.v2.resourcepool.BasicResourcePool.doAcquire(BasicResourcePool.java:1014) at com.mchange.v2.resourcepool.BasicResourcePool.access$800(BasicResourcePool.java:32) at com.mchange.v2.resourcepool.BasicResourcePool$AcquireTask.run(BasicResourcePool.java:1810) at com.mchange.v2.async.ThreadPoolAsynchronousRunner$PoolThread.run(ThreadPoolAsynchronousRunner.java:547) 下面貼一下正常操作本地數據庫時，打印的日志 十二月 07, 2016 9:32:11 下午 com.mchange.v2.log.MLog <clinit> 信息: MLog clients using java 1.4+ standard logging. 十二月 07, 2016 9:32:11 下午 com.mchange.v2.c3p0.C3P0Registry banner 信息: Initializing c3p0-0.9.1.2 [built 21-May-2007 15:04:56; debug? true; trace: 10] 十二月 07, 2016 9:32:11 下午 com.mchange.v2.c3p0.impl.AbstractPoolBackedDataSource getPoolManager 信息: Initializing c3p0 pool... com.mchange.v2.c3p0.ComboPooledDataSource [ acquireIncrement -> 3, acquireRetryAttempt s -> 30, acquireRetryDelay -> 1000, autoCommitOnClose -> false, automaticTestTable -> null, breakAfterAcquireFailure -> false, checkoutTimeout -> 0, connectionCustomizerClassName -> null, connectionTesterClassName -> com.mchange.v2. c3p0.impl.DefaultConnectionTester, dataSourceName -> 1bqvvjb9k1oce1vc1vntxdw|f7df584, debugUnreturnedConnectionStack Traces -> false, description -> null, driverClass -> com.mysql.jdbc.Driver, factoryClassLocation -> null, forceIgnor eUnresolvedTransactions -> false, identityToken -> 1bqvvjb9k1oce1vc1vntxdw|f7df584, idleConnectionTestPeriod -> 0, i nitialPoolSize -> 5, jdbcUrl -> jdbc:mysql://localhost:3306/dbWaterColInfo, maxAdministrativeTaskTime -> 0, maxConne ctionAge -> 0, maxIdleTime -> 30, maxIdleTimeExcessConnections -> 0, maxPoolSize -> 20, maxStatements -> 0, maxState mentsPerConnection -> 100, minPoolSize -> 5, numHelperThreads -> 3, numThreadsAwaitingCheckoutDefaultUser -> 0, pref erredTestQuery -> null, properties -> {user=******, password=******}, propertyCycle -> 0, testConnectionOnCheckin -> false, testConnectionOnCheckout -> false, unreturnedConnectionTimeout -> 0, usesTraditionalReflectiveProxies -> fal se ] 1 aaa test1 test1 null 這是我的查詢代碼: public void tese1() throws SQLException{ QueryRunner qr = new QueryRunner(C3P0Util.getDataSource()); Object[] arr = qr.query("select * from userInfos_t", new ArrayHandler()); for (Object o : arr) { System.out.println(o); } } 我的配置文件： <?xml version="1.0" encoding="UTF-8"?> <c3p0-config> <default-config> <property name="driverClass">com.mysql.jdbc.Driver</property> <property name="jdbcUrl">jdbc:mysql://localhost:3306/dbWaterColInfo</property> <property name="user">root</property> <property name="password">root</property> <property name="initialPoolSize">5</property> <property name="maxIdleTime">30</property> <property name="maxPoolSize">20</property> <property name="minPoolSize">5</property> <property name="maxStatements">0</property> <property name="maxStatementsPerConnection">100</property> </default-config> </c3p0-config> 有朋友知道解決方法的話請告知一下，謝謝了。