java - 无法加载 com.mchange.v2.resourcepool.BasicResourcePool$1DestroyResourceTask。 java.lang.IllegalStateException

Question

我正在使用一个移动网络应用程序，其中数据库部分我使用Hibernate，连接池c3p0，当我在开始工作正常，但是在执行了一些事务(例如选择、保存、更新)之后，我收到以下异常，我不知道为什么会发生，

Sep 22, 2015 12:40:06 PM org.apache.catalina.loader.WebappClassLoader loadClass
INFO: Illegal access: this web application instance has been stopped already.  Could not load com.mchange.v2.resourcepool.BasicResourcePool$1DestroyResourceTask.  The eventual following stack trace is caused by an error thrown for debugging purposes as well as to attempt to terminate the thread which caused the illegal access, and has no functional impact.
java.lang.IllegalStateException
    at org.apache.catalina.loader.WebappClassLoader.loadClass(WebappClassLoader.java:1562)
    at org.apache.catalina.loader.WebappClassLoader.loadClass(WebappClassLoader.java:1521)
    at com.mchange.v2.resourcepool.BasicResourcePool.destroyResource(BasicResourcePool.java:1040)
    at com.mchange.v2.resourcepool.BasicResourcePool.removeResource(BasicResourcePool.java:1507)
    at com.mchange.v2.resourcepool.BasicResourcePool.removeResource(BasicResourcePool.java:1477)
    at com.mchange.v2.resourcepool.BasicResourcePool.cullExpired(BasicResourcePool.java:1565)
    at com.mchange.v2.resourcepool.BasicResourcePool.access$1900(BasicResourcePool.java:44)
    at com.mchange.v2.resourcepool.BasicResourcePool$CullTask.run(BasicResourcePool.java:2089)
    at java.util.TimerThread.mainLoop(Timer.java:512)
    at java.util.TimerThread.run(Timer.java:462)
Exception in thread "C3P0PooledConnectionPoolManager[identityToken->2sa3m19b1vnwmg61s8v1zi|5363e54]-AdminTaskTimer" java.lang.NoClassDefFoundError: com/mchange/v2/resourcepool/BasicResourcePool$1DestroyResourceTask
    at com.mchange.v2.resourcepool.BasicResourcePool.destroyResource(BasicResourcePool.java:1040)
    at com.mchange.v2.resourcepool.BasicResourcePool.removeResource(BasicResourcePool.java:1507)
    at com.mchange.v2.resourcepool.BasicResourcePool.removeResource(BasicResourcePool.java:1477)
    at com.mchange.v2.resourcepool.BasicResourcePool.cullExpired(BasicResourcePool.java:1565)
    at com.mchange.v2.resourcepool.BasicResourcePool.access$1900(BasicResourcePool.java:44)
    at com.mchange.v2.resourcepool.BasicResourcePool$CullTask.run(BasicResourcePool.java:2089)
    at java.util.TimerThread.mainLoop(Timer.java:512)
    at java.util.TimerThread.run(Timer.java:462)
Caused by: java.lang.ClassNotFoundException: com.mchange.v2.resourcepool.BasicResourcePool$1DestroyResourceTask
    at org.apache.catalina.loader.WebappClassLoader.loadClass(WebappClassLoader.java:1676)
    at org.apache.catalina.loader.WebappClassLoader.loadClass(WebappClassLoader.java:1521)
    ... 8 more

Hibernate.cfg.xml

<?xml version="1.0" encoding="UTF-8"?>
<!DOCTYPE hibernate-configuration PUBLIC "-//Hibernate/Hibernate Configuration DTD 3.0//EN" "http://www.hibernate.org/dtd/hibernate-configuration-3.0.dtd">
<hibernate-configuration>
  <session-factory>
    <!-- Database connection settings -->
    <property name="connection.driver_class">org.postgresql.Driver</property>
    <property name="connection.username">postgres</property>
    <property name="connection.password">admin</property>
    <property name="connection.url">jdbc:postgresql://localhost:5432/db</property>

    <!-- SQL dialect -->
    <property name="dialect">com.bss.util.PostgreSQLDialectCustom</property>

    <!-- Enable Hibernate's automatic session context management -->
    <property name="current_session_context_class">thread</property>

    <!-- Echo all executed SQL to stdout -->
    <property name="show_sql">true</property>

    <!-- Use the C3P0 connection pool provider -->
    <property name="hibernate.c3p0.min_size">5</property>
    <property name="hibernate.c3p0.max_size">20</property>
    <property name="hibernate.c3p0.timeout">300</property>
    <property name="hibernate.c3p0.max_statements">50</property>
    <property name="hibernate.c3p0.idle_test_period">3000</property>

    <mapping class="com.bss.model.TestUser"/>
    <mapping class="com.bss.model.ItappFriendlist"/>
    <mapping class="com.bss.model.ItappFriendlistPK"/>
    <mapping class="com.bss.model.User"/>   
    <mapping class="com.bss.model.UserSession"/>    
  </session-factory>
</hibernate-configuration>

Answer 1

所以，您遇到了 tomcat 热重新部署 ClassLoader 问题。

您应该做两件事:

1. 确保当您的应用程序关闭时，您的 Hibernate SessionFactory 也会被 close() 编辑。执行此操作的最佳位置是 ServletContextListener。否则，在热重新部署时，现已废弃的应用程序中的 c3p0 线程将继续运行。请参阅SessionFactory.close()

2. 尝试描述的设置 here防止从失效的ClassLoader中对对象进行杂散引用。您只需添加

<小时/>

<property name="hibernate.c3p0.privilegeSpawnedThreads">true</property>
<property name="hibernate.c3p0.contextClassLoaderSource">library</property>

<小时/>

到你的c3p0配置部分。

(请确保您使用的是最新版本的 c3p0。这些设置是新的。)