今天，在写java程序通过读取c3p0连接池的配置文件来连接数据库时，出现了下面的异常
三月 05, 2020 1:25:07 上午 com.mchange.v2.log.MLog <clinit>
信息: MLog clients using java 1.4+ standard logging.
[Fatal Error] :6:93: 对实体 "serverTimezone" 的引用必须以 ';' 分隔符结尾。
三月 05, 2020 1:25:08 上午 com.mchange.v2.c3p0.cfg.C3P0Config <clinit>
警告: XML configuration disabled! Verify that standard XML libs are available.
org.xml.sax.SAXParseException; lineNumber: 6; columnNumber: 93; 对实体 "serverTimezone" 的引用必须以 ';' 分隔符结尾。
at com.sun.org.apache.xerces.internal.parsers.DOMParser.parse(DOMParser.java:257)
at com.sun.org.apache.xerces.internal.jaxp.DocumentBuilderImpl.parse(DocumentBuilderImpl.java:339)
at javax.xml.parsers.DocumentBuilder.parse(DocumentBuilder.java:121)
at com.mchange.v2.c3p0.cfg.C3P0ConfigXmlUtils.extractXmlConfigFromInputStream(C3P0ConfigXmlUtils.java:136)
at com.mchange.v2.c3p0.cfg.C3P0ConfigXmlUtils.extractXmlConfigFromDefaultResource(C3P0ConfigXmlUtils.java:119)
at com.mchange.v2.c3p0.cfg.DefaultC3P0ConfigFinder.findConfig(DefaultC3P0ConfigFinder.java:49)
at com.mchange.v2.c3p0.cfg.C3P0Config.<clinit>(C3P0Config.java:92)
at com.mchange.v2.c3p0.impl.PoolBackedDataSourceBase.<init>(PoolBackedDataSourceBase.java:50)
at com.mchange.v2.c3p0.impl.AbstractPoolBackedDataSource.<init>(AbstractPoolBackedDataSource.java:62)
at com.mchange.v2.c3p0.ComboPooledDataSource.<init>(ComboPooledDataSource.java:122)
at com.mchange.v2.c3p0.ComboPooledDataSource.<init>(ComboPooledDataSource.java:118)
at test.c3p0.TestC3P0_02.main(TestC3P0_02.java:15)
三月 05, 2020 1:25:09 上午 com.mchange.v2.c3p0.C3P0Registry banner
信息: Initializing c3p0-0.9.2-pre5 [built 29-September-2012 19:59:04 +0000; debug? true; trace: 10]
三月 05, 2020 1:25:09 上午 com.mchange.v2.c3p0.impl.AbstractPoolBackedDataSource getPoolManager
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, dataSourceName -> 1hgf9q9a81a7x1ne12i3kuq|1e80bfe8, debugUnreturnedConnectionStackTraces -> false, description -> null, driverClass -> null, factoryClassLocation -> null, forceIgnoreUnresolvedTransactions -> false, identityToken -> 1hgf9q9a81a7x1ne12i3kuq|1e80bfe8, 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, properties -> {}, propertyCycle -> 0, statementCacheNumDeferredCloseThreads -> 0, testConnectionOnCheckin -> false, testConnectionOnCheckout -> false, unreturnedConnectionTimeout -> 0, userOverrides -> {}, usesTraditionalReflectiveProxies -> false ]
原因：配置文件有误
<?xml version="1.0" encoding="UTF-8"?>
<c3p0-config>
<!-- 默认配置，如果没有指定则使用这个配置 -->
<default-config>
<property name="driverClass">com.mysql.cj.jdbc.Driver</property>
<property name="jdbcUrl">jdbc:mysql://localhost:3306/chapter02?useSSL=false&serverTimezone=UTC</property>
<property name="user">root</property>
<property name="password">1111</property>
<property name="checkoutTimeout">30000</property>
<property name="idleConnectionTestPeriod">30</property>
<property name="initialPoolSize">10</property>
<property name="maxIdleTime">30</property>
<property name="maxPoolSize">100</property>
<property name="minPoolSize">10</property>
<property name="maxStatements">200</property>
<user-overrides user="test-user">
<property name="maxPoolSize">10</property>
<property name="minPoolSize">1</property>
<property name="maxStatements">0</property>
</user-overrides>
</default-config>
这里出现错误的原因是，在&这个符号后面，正确的写法是后面添加‘’ amp； ” ，也就是将URL改为：jdbc:mysql://localhost:3306/chapter02?useSSL=false&；serverTimezone=UTC
这样异常就解决了
运行成功
