运行本节代码各种报错……

二月 19, 2020 1:12:08 下午 org.apache.catalina.loader.WebappClassLoaderBase clearReferencesJdbc
警告: Web应用程序 [shop] 注册了JDBC驱动程序 [com.mysql.cj.jdbc.Driver]，但在Web应用程序停止时无法注销它。 为防止内存泄漏，JDBC驱动程序已被强制取消注册。
二月 19, 2020 1:12:08 下午 org.apache.catalina.loader.WebappClassLoaderBase clearReferencesThreads
警告: Web应用程序[shop]似乎启动了一个名为[C3P0PooledConnectionPoolManager[identityToken->1hge0z2a8phfpe88idz7w|7ac8f89f]-AdminTaskTimer]的线程，但未能停止它。这很可能会造成内存泄漏。线程的堆栈跟踪：[
 java.lang.Object.wait(Native Method)
 java.util.TimerThread.mainLoop(Timer.java:552)
 java.util.TimerThread.run(Timer.java:505)]
二月 19, 2020 1:12:08 下午 org.apache.catalina.loader.WebappClassLoaderBase clearReferencesThreads
警告: Web应用程序[shop]似乎启动了一个名为[C3P0PooledConnectionPoolManager[identityToken->1hge0z2a8phfpe88idz7w|7ac8f89f]-HelperThread-#0]的线程，但未能停止它。这很可能会造成内存泄漏。线程的堆栈跟踪：[
 java.lang.Object.wait(Native Method)
 com.mchange.v2.async.ThreadPoolAsynchronousRunner$PoolThread.run(ThreadPoolAsynchronousRunner.java:635)]
二月 19, 2020 1:12:08 下午 org.apache.catalina.loader.WebappClassLoaderBase clearReferencesThreads
警告: Web应用程序[shop]似乎启动了一个名为[C3P0PooledConnectionPoolManager[identityToken->1hge0z2a8phfpe88idz7w|7ac8f89f]-HelperThread-#1]的线程，但未能停止它。这很可能会造成内存泄漏。线程的堆栈跟踪：[
 java.lang.Object.wait(Native Method)
 com.mchange.v2.async.ThreadPoolAsynchronousRunner$PoolThread.run(ThreadPoolAsynchronousRunner.java:635)]
二月 19, 2020 1:12:08 下午 org.apache.catalina.loader.WebappClassLoaderBase clearReferencesThreads
警告: Web应用程序[shop]似乎启动了一个名为[C3P0PooledConnectionPoolManager[identityToken->1hge0z2a8phfpe88idz7w|7ac8f89f]-HelperThread-#2]的线程，但未能停止它。这很可能会造成内存泄漏。线程的堆栈跟踪：[
 java.lang.Object.wait(Native Method)
 com.mchange.v2.async.ThreadPoolAsynchronousRunner$PoolThread.run(ThreadPoolAsynchronousRunner.java:635)]
二月 19, 2020 1:12:08 下午 org.apache.catalina.loader.WebappClassLoaderBase clearReferencesThreads
警告: Web应用程序[shop]似乎启动了一个名为[mysql-cj-abandoned-connection-cleanup]的线程，但未能停止它。这很可能会造成内存泄漏。线程的堆栈跟踪：[
 java.lang.Object.wait(Native Method)
 java.lang.ref.ReferenceQueue.remove(ReferenceQueue.java:143)
 com.mysql.cj.jdbc.AbandonedConnectionCleanupThread.run(AbandonedConnectionCleanupThread.java:85)
 java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1142)
 java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:617)
 java.lang.Thread.run(Thread.java:745)]
二月 19, 2020 1:12:08 下午 org.apache.jasper.servlet.TldScanner scanJars
信息: 至少有一个JAR被扫描用于TLD但尚未包含TLD。 为此记录器启用调试日志记录，以获取已扫描但未在其中找到TLD的完整JAR列表。 在扫描期间跳过不需要的JAR可以缩短启动时间和JSP编译时间。
二月 19, 2020 1:12:08 下午 org.apache.catalina.core.StandardContext reload
信息: Reloading Context with name [/shop] is completed
二月 19, 2020 1:12:10 下午 org.apache.catalina.loader.WebappClassLoaderBase checkStateForResourceLoading
信息: 非法访问：此Web应用程序实例已停止。无法加载[]。为了调试以及终止导致非法访问的线程，将抛出以下堆栈跟踪。
java.lang.IllegalStateException: 非法访问：此Web应用程序实例已停止。无法加载[]。为了调试以及终止导致非法访问的线程，将抛出以下堆栈跟踪。
    at org.apache.catalina.loader.WebappClassLoaderBase.checkStateForResourceLoading(WebappClassLoaderBase.java:1378)
    at org.apache.catalina.loader.WebappClassLoaderBase.getResource(WebappClassLoaderBase.java:1030)
    at com.mysql.cj.jdbc.AbandonedConnectionCleanupThread.checkThreadContextClassLoader(AbandonedConnectionCleanupThread.java:117)
    at com.mysql.cj.jdbc.AbandonedConnectionCleanupThread.run(AbandonedConnectionCleanupThread.java:84)
    at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1142)
    at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:617)
    at java.lang.Thread.run(Thread.java:745)

CategoryServlet里面的findAll方法执行了
CategoryService里面的findAll方法执行了
二月 19, 2020 1:12:14 下午 com.mchange.v2.log.MLog <clinit>
信息: MLog clients using java 1.4+ standard logging.
二月 19, 2020 1:12:14 下午 com.mchange.v2.c3p0.C3P0Registry banner
信息: Initializing c3p0-0.9.2.1 [built 20-March-2013 10:47:27 +0000; debug? true; trace: 10]
二月 19, 2020 1:12:14 下午 com.mchange.v2.c3p0.management.ActiveManagementCoordinator attemptManageC3P0Registry
警告: A C3P0Registry mbean is already registered. This probably means that an application using c3p0 was undeployed, but not all PooledDataSources were closed prior to undeployment. This may lead to resource leaks over time. Please take care to close all PooledDataSources.
二月 19, 2020 1:12:15 下午 com.mchange.v2.c3p0.cfg.C3P0Config initializeIntPropertyVar
信息: '' is not a legal value for property 'initialPoolSize'. Using default value: 3
二月 19, 2020 1:12:15 下午 com.mchange.v2.c3p0.cfg.C3P0Config initializeIntPropertyVar
信息: '' is not a legal value for property 'maxPoolSize'. Using default value: 15
二月 19, 2020 1:12:15 下午 com.mchange.v2.c3p0.cfg.C3P0Config initializeIntPropertyVar
信息: '' is not a legal value for property 'minPoolSize'. Using default value: 3
二月 19, 2020 1:12:15 下午 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 -> 1hge0z2a8phkmc9c7yczc|62ccf042, debugUnreturnedConnectionStackTraces -> false, description -> null, driverClass -> com.mysql.cj.jdbc.Driver, factoryClassLocation -> null, forceIgnoreUnresolvedTransactions -> false, identityToken -> 1hge0z2a8phkmc9c7yczc|62ccf042, idleConnectionTestPeriod -> 0, initialPoolSize -> 3, jdbcUrl -> jdbc:mysql:///shop?characterEncoding=UTF-8&serverTimezone=UTC&useSSL=false, maxAdministrativeTaskTime -> 0, maxConnectionAge -> 0, maxIdleTime -> 0, maxIdleTimeExcessConnections -> 0, maxPoolSize -> 15, maxStatements -> 0, maxStatementsPerConnection -> 0, minPoolSize -> 3, numHelperThreads -> 3, preferredTestQuery -> null, properties -> {user=******, password=******}, propertyCycle -> 0, statementCacheNumDeferredCloseThreads -> 0, testConnectionOnCheckin -> false, testConnectionOnCheckout -> false, unreturnedConnectionTimeout -> 0, userOverrides -> {}, usesTraditionalReflectiveProxies -> false ]