c3p0 DEBUG STACK TRACE for PoolBackedDataSource.close(). 错误分析

新搭的一个框架，做junit测试时报出以下错误。

java.lang.Exception: DEBUG STACK TRACE for PoolBackedDataSource.close(). at com.mchange.v2.c3p0.impl.AbstractPoolBackedDataSource.close(AbstractPoolBackedDataSource.java:417) at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method) at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:39) at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:25) at java.lang.reflect.Method.invoke(Method.java:597) at org.springframework.beans.factory.support.DisposableBeanAdapter.invokeCustomDestroyMethod(DisposableBeanAdapter.java:208) at org.springframework.beans.factory.support.DisposableBeanAdapter.destroy(DisposableBeanAdapter.java:165) at org.springframework.beans.factory.support.DefaultSingletonBeanRegistry.destroyBean(DefaultSingletonBeanRegistry.java:487) at org.springframework.beans.factory.support.DefaultSingletonBeanRegistry.destroySingleton(DefaultSingletonBeanRegistry.java:462) at org.springframework.beans.factory.support.DefaultSingletonBeanRegistry.destroySingletons(DefaultSingletonBeanRegistry.java:430) at org.springframework.context.support.AbstractApplicationContext.refresh(AbstractApplicationContext.java:388) at org.springframework.context.support.ClassPathXmlApplicationContext.<init>(ClassPathXmlApplicationContext.java:139) at org.springframework.context.support.ClassPathXmlApplicationContext.<init>(ClassPathXmlApplicationContext.java:83) at junit.test.EmpTest.init(EmpTest.java:21) at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method) at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:39) at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:25) at java.lang.reflect.Method.invoke(Method.java:597) at org.junit.internal.runners.ClassRoadie.runBefores(ClassRoadie.java:49) at org.junit.internal.runners.ClassRoadie.runProtected(ClassRoadie.java:36) at org.junit.internal.runners.JUnit4ClassRunner.run(JUnit4ClassRunner.java:42) at org.eclipse.jdt.internal.junit4.runner.JUnit4TestReference.run(JUnit4TestReference.java:46) at org.eclipse.jdt.internal.junit.runner.TestExecution.run(TestExecution.java:38) at org.eclipse.jdt.internal.junit.runner.RemoteTestRunner.runTests(RemoteTestRunner.java:467) at org.eclipse.jdt.internal.junit.runner.RemoteTestRunner.runTests(RemoteTestRunner.java:683) at org.eclipse.jdt.internal.junit.runner.RemoteTestRunner.run(RemoteTestRunner.java:390) at org.eclipse.jdt.internal.junit.runner.RemoteTestRunner.main(RemoteTestRunner.java:197)

这个问题很是不好找，google 下，贴子倒有些，说是有时有这样的问题，有时又没有，有可能是c3p0 的配置参数问题，但没有明确的指出错误的所在。只好慢慢找错误了，时间花了不少，最终还是找出来了。

首先要看到详细的报错信息，加入log4j。

再一次测试时，junit报出如下错误

org.springframework.beans.factory.BeanCreationException: Error creating bean with name 'sessionFactory' defined in class path resource [com/liyi/config/applicationContext-hibernate.xml]: Invocation of init method failed; nested exception is org.hibernate.MappingException: Could not determine type for: Integer, at table: DEPT, for columns: [org.hibernate.mapping.Column(deptNo)] at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.initializeBean(AbstractAutowireCapableBeanFactory.java:1338) at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.doCreateBean(AbstractAutowireCapableBeanFactory.java:473) at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory$1.run(AbstractAutowireCapableBeanFactory.java:409) at java.security.AccessController.doPrivileged(Native Method) at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.createBean(AbstractAutowireCapableBeanFactory.java:380) at org.springframework.beans.factory.support.AbstractBeanFactory$1.getObject(AbstractBeanFactory.java:264) at org.springframework.beans.factory.support.DefaultSingletonBeanRegistry.getSingleton(DefaultSingletonBeanRegistry.java:222) at org.springframework.beans.factory.support.AbstractBeanFactory.doGetBean(AbstractBeanFactory.java:261) at org.springframework.beans.factory.support.AbstractBeanFactory.getBean(AbstractBeanFactory.java:185) at org.springframework.beans.factory.support.AbstractBeanFactory.getBean(AbstractBeanFactory.java:164) at org.springframework.beans.factory.support.DefaultListableBeanFactory.preInstantiateSingletons(DefaultListableBeanFactory.java:423) at org.springframework.context.support.AbstractApplicationContext.finishBeanFactoryInitialization(AbstractApplicationContext.java:728) at org.springframework.context.support.AbstractApplicationContext.refresh(AbstractApplicationContext.java:380) at org.springframework.context.support.ClassPathXmlApplicationContext.<init>(ClassPathXmlApplicationContext.java:139) at org.springframework.context.support.ClassPathXmlApplicationContext.<init>(ClassPathXmlApplicationContext.java:83) at junit.test.EmpTest.init(EmpTest.java:21) at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method) at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:39) at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:25) at java.lang.reflect.Method.invoke(Method.java:597) at org.junit.internal.runners.ClassRoadie.runBefores(ClassRoadie.java:49) at org.junit.internal.runners.ClassRoadie.runProtected(ClassRoadie.java:36) at org.junit.internal.runners.JUnit4ClassRunner.run(JUnit4ClassRunner.java:42) at org.eclipse.jdt.internal.junit4.runner.JUnit4TestReference.run(JUnit4TestReference.java:46) at org.eclipse.jdt.internal.junit.runner.TestExecution.run(TestExecution.java:38) at org.eclipse.jdt.internal.junit.runner.RemoteTestRunner.runTests(RemoteTestRunner.java:467) at org.eclipse.jdt.internal.junit.runner.RemoteTestRunner.runTests(RemoteTestRunner.java:683) at org.eclipse.jdt.internal.junit.runner.RemoteTestRunner.run(RemoteTestRunner.java:390) at org.eclipse.jdt.internal.junit.runner.RemoteTestRunner.main(RemoteTestRunner.java:197) Caused by: org.hibernate.MappingException: Could not determine type for: Integer, at table: DEPT, for columns: [org.hibernate.mapping.Column(deptNo)] at org.hibernate.mapping.SimpleValue.getType(SimpleValue.java:269) at org.hibernate.cfg.Configuration$1.getIdentifierType(Configuration.java:2111) at org.hibernate.type.EntityType.getIdentifierType(EntityType.java:487) at org.hibernate.type.EntityType.getIdentifierOrUniqueKeyType(EntityType.java:512) at org.hibernate.type.ManyToOneType.getColumnSpan(ManyToOneType.java:65) at org.hibernate.mapping.SimpleValue.isValid(SimpleValue.java:253) at org.hibernate.mapping.ToOne.isValid(ToOne.java:82) at org.hibernate.mapping.Property.isValid(Property.java:185) at org.hibernate.mapping.PersistentClass.validate(PersistentClass.java:440) at org.hibernate.mapping.RootClass.validate(RootClass.java:192) at org.hibernate.cfg.Configuration.validate(Configuration.java:1108) at org.hibernate.cfg.Configuration.buildSessionFactory(Configuration.java:1293) at org.springframework.orm.hibernate3.LocalSessionFactoryBean.newSessionFactory(LocalSessionFactoryBean.java:814) at org.springframework.orm.hibernate3.LocalSessionFactoryBean.buildSessionFactory(LocalSessionFactoryBean.java:732) at org.springframework.orm.hibernate3.AbstractSessionFactoryBean.afterPropertiesSet(AbstractSessionFactoryBean.java:211) at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.invokeInitMethods(AbstractAutowireCapableBeanFactory.java:1369) at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.initializeBean(AbstractAutowireCapableBeanFactory.java:1335) ... 28 more

可以很显然的看出是hibernate 实体映射文件的错误。

在hibernate中存在这样一个问题，就是实体属性的类型，有时能用基本类型，但有时用基本类型却报错，这应该是不同的工程中引用的jar包相关。

 

问题总结：

在我的这个工程中错误的原因就是实体属性的类型，将基本类型改为对象类型，并修改映射文件中属性 的type属性。

程序能正常启动，不会报任务错误，表面上看起来像是c3p0的错误，实际是hibernate 实体映射的错误！

 

 

 

刚解决这问题，就把它贴出来了，希望对你有帮助。如果谁能够帮我说明下hibernate 实体属性有时不能用基本类型的原因，本人在此感激不尽！