Java8，Tomcat9.0.26，Spring全系5.2.6，MyBatis3.5.4，IDEA自带的Maven

Log4j报错

log4j在控制台输出：

log4j:ERROR A "org.apache.log4j.ConsoleAppender" object is not assignable to a "org.apache.log4j.Appender" variable.
log4j:ERROR The class "org.apache.log4j.Appender" was loaded by 
log4j:ERROR [java.net.URLClassLoader@6a6824be] whereas object of type 
log4j:ERROR "org.apache.log4j.ConsoleAppender" was loaded by [ParallelWebappClassLoader
  context: j2eeHW0602_war_exploded
  delegate: false
----------> Parent Classloader:
java.net.URLClassLoader@6a6824be
].
log4j:ERROR Could not instantiate appender named "stdout".

log4j.properties文件存放在resources下

内存泄漏

02-Jun-2020 14:57:20.437 警告 [main] org.apache.catalina.loader.WebappClassLoaderBase.clearReferencesThreads The web application [j2eeHW0602_war_exploded] appears to have started a thread named [mysql-cj-abandoned-connection-cleanup] but has failed to stop it. This is very likely to create a memory leak. Stack trace of thread:
 java.lang.Object.wait(Native Method)
 java.lang.ref.ReferenceQueue.remove(ReferenceQueue.java:143)
 com.mysql.jdbc.AbandonedConnectionCleanupThread.run(AbandonedConnectionCleanupThread.java:80)
 java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1142)
 java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:617)
 java.lang.Thread.run(Thread.java:745)

https://blog.csdn.net/weixin_30887919/article/details/95367514