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连接池用配置文件一直报错,不用的话不报

来源：7-2 C3P0连接池的使用

MySuperhero

2019-03-20 17:10:13

"C:\Program Files\Java\jdk1.8.0_91\bin\java.exe" "-javaagent:E:\IntelliJ IDEA 2018.3.5\lib\idea_rt.jar=52757:E:\IntelliJ IDEA 2018.3.5\bin" -Dfile.encoding=UTF-8 -classpath "C:\Program Files\Java\jdk1.8.0_91\jre\lib\charsets.jar;C:\Program Files\Java\jdk1.8.0_91\jre\lib\deploy.jar;C:\Program Files\Java\jdk1.8.0_91\jre\lib\ext\access-bridge-64.jar;C:\Program Files\Java\jdk1.8.0_91\jre\lib\ext\cldrdata.jar;C:\Program Files\Java\jdk1.8.0_91\jre\lib\ext\dnsns.jar;C:\Program Files\Java\jdk1.8.0_91\jre\lib\ext\jaccess.jar;C:\Program Files\Java\jdk1.8.0_91\jre\lib\ext\jfxrt.jar;C:\Program Files\Java\jdk1.8.0_91\jre\lib\ext\localedata.jar;C:\Program Files\Java\jdk1.8.0_91\jre\lib\ext\nashorn.jar;C:\Program Files\Java\jdk1.8.0_91\jre\lib\ext\sunec.jar;C:\Program Files\Java\jdk1.8.0_91\jre\lib\ext\sunjce_provider.jar;C:\Program Files\Java\jdk1.8.0_91\jre\lib\ext\sunmscapi.jar;C:\Program Files\Java\jdk1.8.0_91\jre\lib\ext\sunpkcs11.jar;C:\Program Files\Java\jdk1.8.0_91\jre\lib\ext\zipfs.jar;C:\Program Files\Java\jdk1.8.0_91\jre\lib\javaws.jar;C:\Program Files\Java\jdk1.8.0_91\jre\lib\jce.jar;C:\Program Files\Java\jdk1.8.0_91\jre\lib\jfr.jar;C:\Program Files\Java\jdk1.8.0_91\jre\lib\jfxswt.jar;C:\Program Files\Java\jdk1.8.0_91\jre\lib\jsse.jar;C:\Program Files\Java\jdk1.8.0_91\jre\lib\management-agent.jar;C:\Program Files\Java\jdk1.8.0_91\jre\lib\plugin.jar;C:\Program Files\Java\jdk1.8.0_91\jre\lib\resources.jar;C:\Program Files\Java\jdk1.8.0_91\jre\lib\rt.jar;E:\工作\work1\out\production\work1;E:\jar包\c3p0-0.9.5.2.jar;E:\jar包\c3p0-oracle-thin-extras-0.9.5.2.jar;E:\jar包\dom4j-1.6.jar;E:\jar包\mchange-commons-java-0.2.11.jar;E:\jar包\mysql-connector-java-5.1.44-bin.jar" com.imooc.Demo.Test
三月 20, 2019 5:01:55 下午 com.mchange.v2.log.MLog
信息: MLog clients using java 1.4+ standard logging.
三月 20, 2019 5:01:57 下午 com.mchange.v2.c3p0.C3P0Registry
信息: Initializing c3p0-0.9.5.2 [built 08-December-2015 22:06:04 -0800; debug? true; trace: 10]
三月 20, 2019 5:01:57 下午 com.mchange.v2.c3p0.impl.AbstractPoolBackedDataSource
信息: Initializing c3p0 pool... com.mchange.v2.c3p0.ComboPooledDataSource [ acquireIncrement -> 3, acquireRetryAttempts -> 30, acquireRetryDelay -> 1000, autoCommitOnClose -> false, automaticTestTable -> null, breakAfterAcquireFailure -> false, checkoutTimeout -> 0, connectionCustomizerClassName -> null, connectionTesterClassName -> com.mchange.v2.c3p0.impl.DefaultConnectionTester, contextClassLoaderSource -> caller, dataSourceName -> 1hge2ada116tm5x0ei35p6|5cb0d902, debugUnreturnedConnectionStackTraces -> false, description -> null, driverClass -> null, extensions -> {}, factoryClassLocation -> null, forceIgnoreUnresolvedTransactions -> false, forceSynchronousCheckins -> false, forceUseNamedDriverClass -> false, identityToken -> 1hge2ada116tm5x0ei35p6|5cb0d902, idleConnectionTestPeriod -> 0, initialPoolSize -> 3, jdbcUrl -> null, maxAdministrativeTaskTime -> 0, maxConnectionAge -> 0, maxIdleTime -> 0, maxIdleTimeExcessConnections -> 0, maxPoolSize -> 15, maxStatements -> 0, maxStatementsPerConnection -> 0, minPoolSize -> 3, numHelperThreads -> 3, preferredTestQuery -> null, privilegeSpawnedThreads -> false, properties -> {}, propertyCycle -> 0, statementCacheNumDeferredCloseThreads -> 0, testConnectionOnCheckin -> false, testConnectionOnCheckout -> false, unreturnedConnectionTimeout -> 0, userOverrides -> {}, usesTraditionalReflectiveProxies -> false ]
三月 20, 2019 5:02:27 下午 com.mchange.v2.resourcepool.BasicResourcePool
警告: com.mchange.v2.resourcepool.BasicResourcePool$ScatteredAcquireTask@48a0f094 -- Acquisition Attempt Failed!!! Clearing pending acquires. While trying to acquire a needed new resource, we failed to succeed more than the maximum number of allowed acquisition attempts (30). Last acquisition attempt exception:
java.lang.NullPointerException
    at com.mysql.fabric.jdbc.FabricMySQLDriver.parseFabricURL(FabricMySQLDriver.java:97)
    at com.mysql.fabric.jdbc.FabricMySQLDriver.acceptsURL(FabricMySQLDriver.java:93)
    at java.sql.DriverManager.getDriver(DriverManager.java:299)
    at com.mchange.v2.c3p0.DriverManagerDataSource.driver(DriverManagerDataSource.java:285)
    at com.mchange.v2.c3p0.DriverManagerDataSource.getConnection(DriverManagerDataSource.java:161)
    at com.mchange.v2.c3p0.WrapperConnectionPoolDataSource.getPooledConnection(WrapperConnectionPoolDataSource.java:161)
    at com.mchange.v2.c3p0.WrapperConnectionPoolDataSource.getPooledConnection(WrapperConnectionPoolDataSource.java:147)
    at com.mchange.v2.c3p0.impl.C3P0PooledConnectionPool$1PooledConnectionResourcePoolManager.acquireResource(C3P0PooledConnectionPool.java:202)
    at com.mchange.v2.resourcepool.BasicResourcePool.doAcquire(BasicResourcePool.java:1138)
    at com.mchange.v2.resourcepool.BasicResourcePool.doAcquireAndDecrementPendingAcquiresWithinLockOnSuccess(BasicResourcePool.java:1125)
    at com.mchange.v2.resourcepool.BasicResourcePool.access$700(BasicResourcePool.java:44)
    at com.mchange.v2.resourcepool.BasicResourcePool$ScatteredAcquireTask.run(BasicResourcePool.java:1870)
    at com.mchange.v2.async.ThreadPoolAsynchronousRunner$PoolThread.run(ThreadPoolAsynchronousRunner.java:696)

三月 20, 2019 5:02:27 下午 com.mchange.v2.resourcepool.BasicResourcePool
警告: com.mchange.v2.resourcepool.BasicResourcePool$ScatteredAcquireTask@45251553 -- Acquisition Attempt Failed!!! Clearing pending acquires. While trying to acquire a needed new resource, we failed to succeed more than the maximum number of allowed acquisition attempts (30). Last acquisition attempt exception:
java.lang.NullPointerException
    at com.mysql.fabric.jdbc.FabricMySQLDriver.parseFabricURL(FabricMySQLDriver.java:97)
    at com.mysql.fabric.jdbc.FabricMySQLDriver.acceptsURL(FabricMySQLDriver.java:93)
    at java.sql.DriverManager.getDriver(DriverManager.java:299)
    at com.mchange.v2.c3p0.DriverManagerDataSource.driver(DriverManagerDataSource.java:285)
    at com.mchange.v2.c3p0.DriverManagerDataSource.getConnection(DriverManagerDataSource.java:161)
    at com.mchange.v2.c3p0.WrapperConnectionPoolDataSource.getPooledConnection(WrapperConnectionPoolDataSource.java:161)
    at com.mchange.v2.c3p0.WrapperConnectionPoolDataSource.getPooledConnection(WrapperConnectionPoolDataSource.java:147)
    at com.mchange.v2.c3p0.impl.C3P0PooledConnectionPool$1PooledConnectionResourcePoolManager.acquireResource(C3P0PooledConnectionPool.java:202)
    at com.mchange.v2.resourcepool.BasicResourcePool.doAcquire(BasicResourcePool.java:1138)
    at com.mchange.v2.resourcepool.BasicResourcePool.doAcquireAndDecrementPendingAcquiresWithinLockOnSuccess(BasicResourcePool.java:1125)
    at com.mchange.v2.resourcepool.BasicResourcePool.access$700(BasicResourcePool.java:44)
    at com.mchange.v2.resourcepool.BasicResourcePool$ScatteredAcquireTask.run(BasicResourcePool.java:1870)
    at com.mchange.v2.async.ThreadPoolAsynchronousRunner$PoolThread.run(ThreadPoolAsynchronousRunner.java:696)

三月 20, 2019 5:02:27 下午 com.mchange.v2.resourcepool.BasicResourcePool
警告: com.mchange.v2.resourcepool.BasicResourcePool$ScatteredAcquireTask@43ffb7d1 -- Acquisition Attempt Failed!!! Clearing pending acquires. While trying to acquire a needed new resource, we failed to succeed more than the maximum number of allowed acquisition attempts (30). Last acquisition attempt exception:
java.lang.NullPointerException
    at com.mysql.fabric.jdbc.FabricMySQLDriver.parseFabricURL(FabricMySQLDriver.java:97)
    at com.mysql.fabric.jdbc.FabricMySQLDriver.acceptsURL(FabricMySQLDriver.java:93)
    at java.sql.DriverManager.getDriver(DriverManager.java:299)
    at com.mchange.v2.c3p0.DriverManagerDataSource.driver(DriverManagerDataSource.java:285)
    at com.mchange.v2.c3p0.DriverManagerDataSource.getConnection(DriverManagerDataSource.java:161)
    at com.mchange.v2.c3p0.WrapperConnectionPoolDataSource.getPooledConnection(WrapperConnectionPoolDataSource.java:161)
    at com.mchange.v2.c3p0.WrapperConnectionPoolDataSource.getPooledConnection(WrapperConnectionPoolDataSource.java:147)
    at com.mchange.v2.c3p0.impl.C3P0PooledConnectionPool$1PooledConnectionResourcePoolManager.acquireResource(C3P0PooledConnectionPool.java:202)
    at com.mchange.v2.resourcepool.BasicResourcePool.doAcquire(BasicResourcePool.java:1138)
    at com.mchange.v2.resourcepool.BasicResourcePool.doAcquireAndDecrementPendingAcquiresWithinLockOnSuccess(BasicResourcePool.java:1125)
    at com.mchange.v2.resourcepool.BasicResourcePool.access$700(BasicResourcePool.java:44)
    at com.mchange.v2.resourcepool.BasicResourcePool$ScatteredAcquireTask.run(BasicResourcePool.java:1870)
    at com.mchange.v2.async.ThreadPoolAsynchronousRunner$PoolThread.run(ThreadPoolAsynchronousRunner.java:696)

三月 20, 2019 5:02:27 下午 com.mchange.v2.resourcepool.BasicResourcePool
警告: Having failed to acquire a resource, com.mchange.v2.resourcepool.BasicResourcePool@6aceb1a5 is interrupting all Threads waiting on a resource to check out. Will try again in response to new client requests.
三月 20, 2019 5:02:27 下午 com.mchange.v2.resourcepool.BasicResourcePool
警告: Having failed to acquire a resource, com.mchange.v2.resourcepool.BasicResourcePool@6aceb1a5 is interrupting all Threads waiting on a resource to check out. Will try again in response to new client requests.
三月 20, 2019 5:02:27 下午 com.mchange.v2.resourcepool.BasicResourcePool
警告: Having failed to acquire a resource, com.mchange.v2.resourcepool.BasicResourcePool@6aceb1a5 is interrupting all Threads waiting on a resource to check out. Will try again in response to new client requests.
java.sql.SQLException: Connections could not be acquired from the underlying database!
    at com.mchange.v2.sql.SqlUtils.toSQLException(SqlUtils.java:118)
    at com.mchange.v2.c3p0.impl.C3P0PooledConnectionPool.checkoutPooledConnection(C3P0PooledConnectionPool.java:692)
    at com.mchange.v2.c3p0.impl.AbstractPoolBackedDataSource.getConnection(AbstractPoolBackedDataSource.java:140)
    at com.imooc.Demo.Test.test(Test.java:24)
    at com.imooc.Demo.Test.main(Test.java:11)
Caused by: com.mchange.v2.resourcepool.CannotAcquireResourceException: A ResourcePool could not acquire a resource from its primary factory or source.
    at com.mchange.v2.resourcepool.BasicResourcePool.awaitAvailable(BasicResourcePool.java:1469)
    at com.mchange.v2.resourcepool.BasicResourcePool.prelimCheckoutResource(BasicResourcePool.java:644)
    at com.mchange.v2.resourcepool.BasicResourcePool.checkoutResource(BasicResourcePool.java:554)
    at com.mchange.v2.c3p0.impl.C3P0PooledConnectionPool.checkoutAndMarkConnectionInUse(C3P0PooledConnectionPool.java:758)
    at com.mchange.v2.c3p0.impl.C3P0PooledConnectionPool.checkoutPooledConnection(C3P0PooledConnectionPool.java:685)
    ... 3 more
Caused by: java.lang.NullPointerException
    at com.mysql.fabric.jdbc.FabricMySQLDriver.parseFabricURL(FabricMySQLDriver.java:97)
    at com.mysql.fabric.jdbc.FabricMySQLDriver.acceptsURL(FabricMySQLDriver.java:93)
    at java.sql.DriverManager.getDriver(DriverManager.java:299)
    at com.mchange.v2.c3p0.DriverManagerDataSource.driver(DriverManagerDataSource.java:285)
    at com.mchange.v2.c3p0.DriverManagerDataSource.getConnection(DriverManagerDataSource.java:161)
    at com.mchange.v2.c3p0.WrapperConnectionPoolDataSource.getPooledConnection(WrapperConnectionPoolDataSource.java:161)
    at com.mchange.v2.c3p0.WrapperConnectionPoolDataSource.getPooledConnection(WrapperConnectionPoolDataSource.java:147)
    at com.mchange.v2.c3p0.impl.C3P0PooledConnectionPool$1PooledConnectionResourcePoolManager.acquireResource(C3P0PooledConnectionPool.java:202)
    at com.mchange.v2.resourcepool.BasicResourcePool.doAcquire(BasicResourcePool.java:1138)
    at com.mchange.v2.resourcepool.BasicResourcePool.doAcquireAndDecrementPendingAcquiresWithinLockOnSuccess(BasicResourcePool.java:1125)
    at com.mchange.v2.resourcepool.BasicResourcePool.access$700(BasicResourcePool.java:44)
    at com.mchange.v2.resourcepool.BasicResourcePool$ScatteredAcquireTask.run(BasicResourcePool.java:1870)
    at com.mchange.v2.async.ThreadPoolAsynchronousRunner$PoolThread.run(ThreadPoolAsynchronousRunner.java:696)

写回答

3回答

好帮手慕阿满

2019-03-20

已采纳

同学你好，在配置文件中，应该是<default-config></default-config>而不是<named-config></named-config>，如：

http://img.mukewang.com/climg/5c92227b00011f8104280268.jpg

同学修改一下再试试，如果还有问题，建议同学去掉之后的参数配置，只留下如上6个配置再试试。

祝：学习愉快~

0

MySuperhero

提问者

2019-03-20

代码:
public class Test {
   public static void main(String[] args) {
       test();
   }
   public static void test(){
       Connection conn=null;
       PreparedStatement pre=null;
       ResultSet re=null;
       try{
           ComboPooledDataSource com =new ComboPooledDataSource();
//            com.setDriverClass("com.mysql.cj.jdbc.Driver");
//            com.setJdbcUrl("jdbc:mysql://localhost:3306/books?useSSL=false&amp;serverTimezone=UTC&amp;allowPublicKeyRetrieval=true");
//            com.setUser("root");
//            com.setPassword("123456");

           conn=com.getConnection();
           String sql="select *from book";
           pre=conn.prepareStatement(sql);
           re=pre.executeQuery();
           while(re.next()){
               System.out.println(re.getString("bookname"));
           }


       }catch (Exception e) {
           e.printStackTrace();
       }finally{
           Demo.closs(conn,pre,re);
       }
配置文件:

<?xml version="1.0" encoding="UTF-8"?>
<c3p0-config>
   <named-config>
       <!-- 配置数据库用户名 -->
       <property name="user">root</property>
       <!-- 配置数据库密码 -->
       <property name="password">123456</property>
       <!-- 配置数据库链接地址 -->
       <property name="jdbcUrl">jdbc:mysql://localhost:3306/books?useSSL=false&amp;serverTimezone=UTC&amp;allowPublicKeyRetrieval=true</property>
       <!-- 配置数据库驱动 -->
       <property name="driverClass">com.mysql.cj.jdbc.Driver</property>
       <!-- 数据库连接池一次性向数据库要多少个连接对象 -->
       <property name="acquireIncrement">20</property>
       <!-- 初始化连接数 -->
       <property name="initialPoolSize">10</property>
       <!-- 最小连接数 -->
       <property name="minPoolSize">5</property>
       <!--连接池中保留的最大连接数。Default: 15 -->
       <property name="maxPoolSize">30</property>
       <!--JDBC的标准参数，用以控制数据源内加载的PreparedStatements数量。但由于预缓存的statements 属于单个connection而不是整个连接池。所以设置这个参数需要考虑到多方面的因素。如果maxStatements与maxStatementsPerConnection均为0，则缓存被关闭。Default:0 -->
       <property name="maxStatements">0</property>
       <!--maxStatementsPerConnection定义了连接池内单个连接所拥有的最大缓存statements数。Default: 0 -->
       <property name="maxStatementsPerConnection">0</property>
       <!--c3p0是异步操作的，缓慢的JDBC操作通过帮助进程完成。扩展这些操作可以有效的提升性能 通过多线程实现多个操作同时被执行。Default:3 -->
       <property name="numHelperThreads">3</property>
       <!--用户修改系统配置参数执行前最多等待300秒。Default: 300 -->
       <property name="propertyCycle">3</property>
       <!-- 获取连接超时设置 默认是一直等待单位毫秒 -->
       <property name="checkoutTimeout">1000</property>
       <!--每多少秒检查所有连接池中的空闲连接。Default: 0 -->
       <property name="idleConnectionTestPeriod">3</property>
       <!--最大空闲时间,多少秒内未使用则连接被丢弃。若为0则永不丢弃。Default: 0 -->
       <property name="maxIdleTime">10</property>
       <!--配置连接的生存时间，超过这个时间的连接将由连接池自动断开丢弃掉。当然正在使用的连接不会马上断开，而是等待它close再断开。配置为0的时候则不会对连接的生存时间进行限制。 -->
       <property name="maxIdleTimeExcessConnections">5</property>
       <!--两次连接中间隔时间，单位毫秒。Default: 1000 -->
       <property name="acquireRetryDelay">1000</property>
       <!--c3p0将建一张名为Test的空表，并使用其自带的查询语句进行测试。如果定义了这个参数那么属性preferredTestQuery将被忽略。你不能在这张Test表上进行任何操作，它将只供c3p0测试使用。Default: null -->
       <property name="automaticTestTable">Test</property>
       <!-- 获取connnection时测试是否有效 -->
       <property name="testConnectionOnCheckin">true</property>
   </named-config>
</c3p0-config>

0

好帮手慕阿满

2019-03-20

建议同学将代码及配置文件贴一下，方便我们帮你查看具体问题。贴代码时，记得贴在回答中。

祝：学习愉快~

0

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