我使用Hibernate，jersey framework 创建了一个 Restful服务。最后，我已将其部署到 tomcat8服务器，但
问题是：
服务在2-3天后停止工作（发生了一些错误），所以我必须重新启动服务器才能正常工作。然后在2-3天后发生同样的问题。
这是我正确关闭会话的代码：
public Category GetCategory(int id) throws Exception {
Session session = HibernateSessionManager.getSession();
Category category = new Category();
Transaction tx = null;
try {
tx = session.beginTransaction();
category = (Category) session.load(Category.class, id);
tx.commit();
} catch (Exception e) {
if (tx != null) {
tx.rollback();
}
throw e;
} finally {
session.close();
}
return category;
这是Hibernate配置：
<property name="c3p0.min_size">20</property>
<property name="c3p0.max_size">150</property>
<property name="c3p0.minPoolSize">20</property>
<property name="c3p0.maxPoolSize">150</property>
<property name="c3p0.numHelperThreads">10</property>
<property name="c3p0.timeout">300</property>
<property name="c3p0.max_statements">350</property>
<property name="c3p0.idle_test_period">300</property>
<property name="c3p0.validate">true</property>
<property name="c3p0.preferredTestQuery">SELECT 1</property>
<property name="c3p0.testConnectionOnCheckin">true</property>
<property name="c3p0.testConnectionOnCheckout">false</property>
这是错误日志：
errorjava.lang.IllegalStateException: Can't overwrite cause with java.lang.IllegalStateException: Illegal access: this web application instance has been stopped already. Could not load com.mchange.v2.sql.SqlUtils. 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.
258919314 [http-nio-8080-exec-24] WARN com.mchange.v2.resourcepool.BasicResourcePool - com.mchange.v2.resourcepool.BasicResourcePool@578b3b27 -- an attempt to checkout a resource was interrupted, and the pool is still live: some other thread must have interrupted the Thread attempting checkout!
java.lang.InterruptedException
at java.lang.Object.wait(Native Method)
at com.mchange.v2.resourcepool.BasicResourcePool.awaitAvailable(BasicResourcePool.java:1459)
at com.mchange.v2.resourcepool.BasicResourcePool.prelimCheckoutResource(BasicResourcePool.java:639)
at com.mchange.v2.resourcepool.BasicResourcePool.checkoutResource(BasicResourcePool.java:549)
at com.mchange.v2.c3p0.impl.C3P0PooledConnectionPool.checkoutAndMarkConnectionInUse(C3P0PooledConnectionPool.java:756)
at com.mchange.v2.c3p0.impl.C3P0PooledConnectionPool.checkoutPooledConnection(C3P0PooledConnectionPool.java:683)
at com.mchange.v2.c3p0.impl.AbstractPoolBackedDataSource.getConnection(AbstractPoolBackedDataSource.java:140)
at org.hibernate.service.jdbc.connections.internal.C3P0ConnectionProvider.getConnection(C3P0ConnectionProvider.java:84)
at org.hibernate.internal.AbstractSessionImpl$NonContextualJdbcConnectionAccess.obtainConnection(AbstractSessionImpl.java:292)
at org.hibernate.engine.jdbc.internal.LogicalConnectionImpl.obtainConnection(LogicalConnectionImpl.java:214)
at org.hibernate.engine.jdbc.internal.LogicalConnectionImpl.getConnection(LogicalConnectionImpl.java:157)
at org.hibernate.engine.transaction.spi.AbstractTransactionImpl.begin(AbstractTransactionImpl.java:160)
at org.hibernate.internal.SessionImpl.beginTransaction(SessionImpl.java:1426)
at Dao.CaseDb.GetCases(CaseDb.java:34)
at Model.CaseManager.GetCases(CaseManager.java:23)
at WebService.CaseService.getCases(CaseService.java:61)
at sun.reflect.GeneratedMethodAccessor60.invoke(Unknown Source)
at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
at java.lang.reflect.Method.invoke(Method.java:483)
at org.glassfish.jersey.server.model.internal.ResourceMethodInvocationHandlerFactory$1.invoke(ResourceMethodInvocationHandlerFactory.java:81)
at org.glassfish.jersey.server.model.internal.AbstractJavaResourceMethodDispatcher$1.run(AbstractJavaResourceMethodDispatcher.java:151)
at org.glassfish.jersey.server.model.internal.AbstractJavaResourceMethodDispatcher.invoke(AbstractJavaResourceMethodDispatcher.java:171)
at org.glassfish.jersey.server.model.internal.JavaResourceMethodDispatcherProvider$TypeOutInvoker.doDispatch(JavaResourceMethodDispatcherProvider.java:195)
at org.glassfish.jersey.server.model.internal.AbstractJavaResourceMethodDispatcher.dispatch(AbstractJavaResourceMethodDispatcher.java:104)
at org.glassfish.jersey.server.model.ResourceMethodInvoker.invoke(ResourceMethodInvoker.java:384)
at org.glassfish.jersey.server.model.ResourceMethodInvoker.apply(ResourceMethodInvoker.java:342)
at org.glassfish.jersey.server.model.ResourceMethodInvoker.apply(ResourceMethodInvoker.java:101)
at org.glassfish.jersey.server.ServerRuntime$1.run(ServerRuntime.java:271)
at org.glassfish.jersey.internal.Errors$1.call(Errors.java:271)
at org.glassfish.jersey.internal.Errors$1.call(Errors.java:267)
at org.glassfish.jersey.internal.Errors.process(Errors.java:315)
at org.glassfish.jersey.internal.Errors.process(Errors.java:297)
at org.glassfish.jersey.internal.Errors.process(Errors.java:267)
at org.glassfish.jersey.process.internal.RequestScope.runInScope(RequestScope.java:297)
at org.glassfish.jersey.server.ServerRuntime.process(ServerRuntime.java:254)
at org.glassfish.jersey.server.ApplicationHandler.handle(ApplicationHandler.java:1030)
at org.glassfish.jersey.servlet.WebComponent.service(WebComponent.java:373)
at org.glassfish.jersey.servlet.ServletContainer.service(ServletContainer.java:381)
at org.glassfish.jersey.servlet.ServletContainer.service(ServletContainer.java:344)
at org.glassfish.jersey.servlet.ServletContainer.service(ServletContainer.java:221)
at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:291)
at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:206)
at org.apache.tomcat.websocket.server.WsFilter.doFilter(WsFilter.java:52)
at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:239)
at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:206)
at org.apache.catalina.core.StandardWrapperValve.invoke(StandardWrapperValve.java:219)
at org.apache.catalina.core.StandardContextValve.invoke(StandardContextValve.java:106)
at org.apache.catalina.authenticator.AuthenticatorBase.invoke(AuthenticatorBase.java:505)
at org.apache.catalina.core.StandardHostValve.invoke(StandardHostValve.java:142)
at org.apache.catalina.valves.ErrorReportValve.invoke(ErrorReportValve.java:79)
at org.apache.catalina.valves.AbstractAccessLogValve.invoke(AbstractAccessLogValve.java:610)
at org.apache.catalina.core.StandardEngineValve.invoke(StandardEngineValve.java:88)
at org.apache.catalina.connector.CoyoteAdapter.service(CoyoteAdapter.java:534)