关于c3p0连接池使用xml配置出现的一些错误

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最新推荐文章于 2021-05-29 17:12:49 发布

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分类专栏：错误文章标签： c3p0

本文链接：https://blog.youkuaiyun.com/weixin_42048382/article/details/96476394

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本文介绍了一个关于C3P0连接池配置文件中出现的错误，并详细记录了解决过程。错误提示为XML实体引用未正确结束，通过检查发现URL参数中的&符号未转义导致问题。

错误信息如下

7月 19, 2019 10:53:22 上午 com.mchange.v2.log.MLog 
信息: MLog clients using java 1.4+ standard logging.
[Fatal Error] :8:100: 对实体 "characterEncoding" 的引用必须以 ';' 分隔符结尾。
7月 19, 2019 10:53:22 上午 com.mchange.v2.c3p0.cfg.C3P0Config 
严重: An error occurred while trying to parse the XML configuration!
7月 19, 2019 10:53:22 上午 com.mchange.v2.c3p0.cfg.C3P0Config 
严重: XML CONFIGURATION IGNORED!
org.xml.sax.SAXParseException; lineNumber: 8; columnNumber: 100; 对实体 "characterEncoding" 的引用必须以 ';' 分隔符结尾。
	at java.xml/com.sun.org.apache.xerces.internal.parsers.DOMParser.parse(DOMParser.java:261)
	at java.xml/com.sun.org.apache.xerces.internal.jaxp.DocumentBuilderImpl.parse(DocumentBuilderImpl.java:339)
	at java.xml/javax.xml.parsers.DocumentBuilder.parse(DocumentBuilder.java:122)
	at com.mchange.v2.c3p0.cfg.C3P0ConfigXmlUtils.extractXmlConfigFromInputStream(C3P0ConfigXmlUtils.java:206)
	at com.mchange.v2.c3p0.cfg.C3P0ConfigXmlUtils.extractXmlConfigFromDefaultResource(C3P0ConfigXmlUtils.java:131)
	at com.mchange.v2.c3p0.cfg.DefaultC3P0ConfigFinder.findConfig(DefaultC3P0ConfigFinder.java:77)
	at com.mchange.v2.c3p0.cfg.C3P0Config.findLibraryC3P0Config(C3P0Config.java:188)
	at com.mchange.v2.c3p0.cfg.C3P0Config.<clinit>(C3P0Config.java:144)
	at com.mchange.v2.c3p0.impl.PoolBackedDataSourceBase.<init>(PoolBackedDataSourceBase.java:54)
	at com.mchange.v2.c3p0.impl.AbstractPoolBackedDataSource.<init>(AbstractPoolBackedDataSource.java:74)
	at com.mchange.v2.c3p0.AbstractComboPooledDataSource.<init>(AbstractComboPooledDataSource.java:142)
	at com.mchange.v2.c3p0.AbstractComboPooledDataSource.<init>(AbstractComboPooledDataSource.java:138)
	at com.mchange.v2.c3p0.AbstractComboPooledDataSource.<init>(AbstractComboPooledDataSource.java:215)
	at com.mchange.v2.c3p0.ComboPooledDataSource.<init>(ComboPooledDataSource.java:53)
	at jdbcdemo.C3p0Test.test1(C3p0Test.java:17)
	at java.base/jdk.internal.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
	at java.base/jdk.internal.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:62)
	at java.base/jdk.internal.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
	at java.base/java.lang.reflect.Method.invoke(Method.java:566)
	at org.junit.platform.commons.util.ReflectionUtils.invokeMethod(ReflectionUtils.java:515)
	at org.junit.jupiter.engine.execution.ExecutableInvoker.invoke(ExecutableInvoker.java:115)
	at org.junit.jupiter.engine.descriptor.TestMethodTestDescriptor.lambda$invokeTestMethod$6(TestMethodTestDescriptor.java:171)
	at org.junit.platform.engine.support.hierarchical.ThrowableCollector.execute(ThrowableCollector.java:72)
	at org.junit.jupiter.engine.descriptor.TestMethodTestDescriptor.invokeTestMethod(TestMethodTestDescriptor.java:167)
	at org.junit.jupiter.engine.descriptor.TestMethodTestDescriptor.execute(TestMethodTestDescriptor.java:114)
	at org.junit.jupiter.engine.descriptor.TestMethodTestDescriptor.execute(TestMethodTestDescriptor.java:59)
	at org.junit.platform.engine.support.hierarchical.NodeTestTask.lambda$executeRecursively$5(NodeTestTask.java:105)
	at org.junit.platform.engine.support.hierarchical.ThrowableCollector.execute(ThrowableCollector.java:72)
	at org.junit.platform.engine.support.hierarchical.NodeTestTask.executeRecursively(NodeTestTask.java:95)
	at org.junit.platform.engine.support.hierarchical.NodeTestTask.execute(NodeTestTask.java:71)
	at java.base/java.util.ArrayList.forEach(ArrayList.java:1540)
	at org.junit.platform.engine.support.hierarchical.SameThreadHierarchicalTestExecutorService.invokeAll(SameThreadHierarchicalTestExecutorService.java:38)
	at org.junit.platform.engine.support.hierarchical.NodeTestTask.lambda$executeRecursively$5(NodeTestTask.java:110)
	at org.junit.platform.engine.support.hierarchical.ThrowableCollector.execute(ThrowableCollector.java:72)
	at org.junit.platform.engine.support.hierarchical.NodeTestTask.executeRecursively(NodeTestTask.java:95)
	at org.junit.platform.engine.support.hierarchical.NodeTestTask.execute(NodeTestTask.java:71)
	at java.base/java.util.ArrayList.forEach(ArrayList.java:1540)
	at org.junit.platform.engine.support.hierarchical.SameThreadHierarchicalTestExecutorService.invokeAll(SameThreadHierarchicalTestExecutorService.java:38)
	at org.junit.platform.engine.support.hierarchical.NodeTestTask.lambda$executeRecursively$5(NodeTestTask.java:110)
	at org.junit.platform.engine.support.hierarchical.ThrowableCollector.execute(ThrowableCollector.java:72)
	at org.junit.platform.engine.support.hierarchical.NodeTestTask.executeRecursively(NodeTestTask.java:95)
	at org.junit.platform.engine.support.hierarchical.NodeTestTask.execute(NodeTestTask.java:71)
	at org.junit.platform.engine.support.hierarchical.SameThreadHierarchicalTestExecutorService.submit(SameThreadHierarchicalTestExecutorService.java:32)
	at org.junit.platform.engine.support.hierarchical.HierarchicalTestExecutor.execute(HierarchicalTestExecutor.java:57)
	at org.junit.platform.engine.support.hierarchical.HierarchicalTestEngine.execute(HierarchicalTestEngine.java:51)
	at org.junit.platform.launcher.core.DefaultLauncher.execute(DefaultLauncher.java:220)
	at org.junit.platform.launcher.core.DefaultLauncher.lambda$execute$6(DefaultLauncher.java:188)
	at org.junit.platform.launcher.core.DefaultLauncher.withInterceptedStreams(DefaultLauncher.java:202)
	at org.junit.platform.launcher.core.DefaultLauncher.execute(DefaultLauncher.java:181)
	at org.junit.platform.launcher.core.DefaultLauncher.execute(DefaultLauncher.java:128)
	at org.eclipse.jdt.internal.junit5.runner.JUnit5TestReference.run(JUnit5TestReference.java:89)
	at org.eclipse.jdt.internal.junit.runner.TestExecution.run(TestExecution.java:41)
	at org.eclipse.jdt.internal.junit.runner.RemoteTestRunner.runTests(RemoteTestRunner.java:541)
	at org.eclipse.jdt.internal.junit.runner.RemoteTestRunner.runTests(RemoteTestRunner.java:763)
	at org.eclipse.jdt.internal.junit.runner.RemoteTestRunner.run(RemoteTestRunner.java:463)
	at org.eclipse.jdt.internal.junit.runner.RemoteTestRunner.main(RemoteTestRunner.java:209)

7月 19, 2019 10:53:23 上午 com.mchange.v2.c3p0.C3P0Registry 
信息: Initializing c3p0-0.9.5.4 [built 23-March-2019 23:00:48 -0700; debug? true; trace: 10]
7月 19, 2019 10:53:23 上午 com.mchange.v2.c3p0.cfg.C3P0Config 
警告: named-config with name 'hello' does not exist. Using default-config.
7月 19, 2019 10:53:23 上午 com.mchange.v2.c3p0.cfg.C3P0Config 
警告: named-config with name 'hello' does not exist. Using default-config extensions.
7月 19, 2019 10:53:23 上午 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 -> hello, debugUnreturnedConnectionStackTraces -> false, description -> null, driverClass -> null, extensions -> {}, factoryClassLocation -> null, forceIgnoreUnresolvedTransactions -> false, forceSynchronousCheckins -> false, forceUseNamedDriverClass -> false, identityToken -> 1hge8sha429e3oj138l5bo|51c668e3, 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 ]

xml配置信息如下

<?xml version="1.0" encoding="UTF-8"?>
<c3p0-config>

	<named-config name="hello">
		<!-- 连接数据源的基本属性 -->
		<property name="user">root</property>
		<property name="password">root</property>
		<property name="jdbcUrl">jdbc:mysql://localhost:3306/test_ceshi?useUnicode=true&characterEncoding=utf-8&zeroDateTimeBehavior=convertToNull&serverTimezone=GMT%2B8&useSSL=false
		</property>
		<property name="driverClass">com.mysql.cj.jdbc.Driver</property>
		<!-- 若数据库连接池中的连接数不足时,一次向数据库服务器申请多少个连接 -->
		<property name="acquireIncrement">5</property>
		<!-- 初始化数据源连接池时的连接数量 -->
		<property name="initialPoolSize">10</property>
		<!-- 数据池中最小的连接数 -->
		<property name="minPoolSize">10</property>
		<!-- 数据池中最大的连接数 -->
		<property name="maxPoolSize">50</property><!-- intergalactoApp adopts a different 
			approach to configuring statement caching -->
		<!-- c3p0数据库连接池可以维护的Statement的个数 -->
		<property name="maxStatements">20</property>
		<!-- 每个连接可以同时使用多少个Statement的个数 -->
		<property name="maxStatementsPerConnection">5</property>
	</named-config>

</c3p0-config>

各种找原因，各种对配置文件的参数，发现没什么问题，错误提示说驱动不对，又去看jar包，也有，往上翻了翻，发现

[Fatal Error] :8:100: 对实体 "characterEncoding" 的引用必须以 ';' 分隔符结尾。

难道是因为参数有特殊符号？
参数只有url中有&，使用&转义之后，果然

7月 19, 2019 10:57:32 上午 com.mchange.v2.log.MLog 
信息: MLog clients using java 1.4+ standard logging.
7月 19, 2019 10:57:32 上午 com.mchange.v2.c3p0.C3P0Registry 
信息: Initializing c3p0-0.9.5.4 [built 23-March-2019 23:00:48 -0700; debug? true; trace: 10]
7月 19, 2019 10:57:32 上午 com.mchange.v2.c3p0.impl.AbstractPoolBackedDataSource 
信息: Initializing c3p0 pool... com.mchange.v2.c3p0.ComboPooledDataSource [ acquireIncrement -> 5, acquireRetryAttempts -> 30, acquireRetryDelay -> 1000, autoCommitOnClose -> false, automaticTestTable -> null, breakAfterAcquireFailure -> false, checkoutTimeout -> 0, connectionCustomizerClassName -> null, connectionTesterClassName -> com.mchange.v2.c3p0.impl.DefaultConnectionTester, contextClassLoaderSource -> caller, dataSourceName -> hello, debugUnreturnedConnectionStackTraces -> false, description -> null, driverClass -> com.mysql.cj.jdbc.Driver, extensions -> {}, factoryClassLocation -> null, forceIgnoreUnresolvedTransactions -> false, forceSynchronousCheckins -> false, forceUseNamedDriverClass -> false, identityToken -> 1hge8sha429jg9n5jg5wu|f09733f, idleConnectionTestPeriod -> 0, initialPoolSize -> 10, jdbcUrl -> jdbc:mysql://localhost:3306/test_ceshi?useUnicode=true&characterEncoding=utf-8&zeroDateTimeBehavior=convertToNull&serverTimezone=GMT%2B8&useSSL=false, maxAdministrativeTaskTime -> 0, maxConnectionAge -> 0, maxIdleTime -> 0, maxIdleTimeExcessConnections -> 0, maxPoolSize -> 50, maxStatements -> 20, maxStatementsPerConnection -> 5, minPoolSize -> 10, numHelperThreads -> 3, preferredTestQuery -> null, privilegeSpawnedThreads -> false, properties -> {password=******, user=******}, propertyCycle -> 0, statementCacheNumDeferredCloseThreads -> 0, testConnectionOnCheckin -> false, testConnectionOnCheckout -> false, unreturnedConnectionTimeout -> 0, userOverrides -> {}, usesTraditionalReflectiveProxies -> false ]
com.mchange.v2.c3p0.impl.NewProxyConnection@492691d7 [wrapping: com.mysql.cj.jdbc.ConnectionImpl@55dea670]

就是因为xml文档中的&符号需要转义。