我已将Spring应用程序配置为使用Hibernate作为JPA提供程序。应用程序上下文如下所示：
<beans xmlns="http://www.springframework.org/schema/beans"
xmlns:context="http://www.springframework.org/schema/context"
xmlns:util="http://www.springframework.org/schema/util"
xmlns:aop="http://www.springframework.org/schema/aop"
xmlns:tx="http://www.springframework.org/schema/tx"
xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
xsi:schemaLocation="
http://www.springframework.org/schema/beans http://www.springframework.org/schema/beans/spring-beans-3.0.xsd
http://www.springframework.org/schema/context http://www.springframework.org/schema/context/spring-context-3.0.xsd
http://www.springframework.org/schema/util http://www.springframework.org/schema/util/spring-util-3.0.xsd
http://www.springframework.org/schema/aop http://www.springframework.org/schema/aop/spring-aop-3.0.xsd
http://www.springframework.org/schema/tx http://www.springframework.org/schema/tx/spring-tx-3.0.xsd">
<context:component-scan base-package="com.med.persistence.magic.*"/>
<aop:aspectj-autoproxy />
<!-- Load DB config file -->
<bean class="org.springframework.beans.factory.config.PropertyPlaceholderConfigurer">
<property name="ignoreResourceNotFound" value="true" />
<property name="ignoreUnresolvablePlaceholders" value="true" />
<property name="searchSystemEnvironment" value="true" />
<property name="systemPropertiesMode">
<util:constant
static-field="org.springframework.beans.factory.config.PropertyPlaceholderConfigurer.SYSTEM_PROPERTIES_MODE_OVERRIDE" />
</property>
<property name="locations">
<list>
<value>classpath:dev.db.properties</value>
<!-- <value>file:///usr/share/tomcat6/conf/hx_db.conf</value>-->
</list>
</property>
</bean>
<tx:annotation-driven transaction-manager="transactionManager"/>
<bean id="transactionManager" class = "org.springframework.orm.jpa.JpaTransactionManager">
<property name="entityManagerFactory" ref="entityManagerFactory"/>
</bean>
<bean id="jpaAdapter" class="org.springframework.orm.jpa.vendor.HibernateJpaVendorAdapter">
<property name="showSql" value="true" />
</bean>
<bean id="entityManagerFactory" class="org.springframework.orm.jpa.LocalContainerEntityManagerFactoryBean">
<property name="dataSource" ref="dataSource" />
<property name="persistenceUnitName" value="MagicPersistenceUnit" />
<property name="jpaVendorAdapter" ref="jpaAdapter" />
<property name="jpaDialect">
<bean class="org.springframework.orm.jpa.vendor.HibernateJpaDialect"/>
</property>
<property name="jpaProperties">
<props>
<prop key="hibernate.hbm2ddl.auto">validate</prop>
<prop key="hibernate.dialect">org.hibernate.dialect.Oracle10gDialect</prop>
<!-- <prop key="hibernate.connection.provider_class">org.hibernate.connection.C3P0ConnectionProvider</prop>-->
<!-- <prop key="hibernate.c3p0.maxSize">25</prop>-->
<!-- <prop key="hibernate.c3p0.minSize">1</prop>-->
<!-- <prop key="hibernate.c3p0.acquireIncrement">1</prop>-->
<!-- <prop key="hibernate.c3p0.idleTestPeriod">300</prop>-->
<!-- <prop key="hibernate.c3p0.maxStatements">0</prop>-->
<!-- <prop key="hibernate.c3p0.timeout">300</prop>-->
<!-- <prop key="hibernate.c3p0.checkoutTimeout">0</prop>-->
<!-- <prop key="hibernate.c3p0.preferredTestQuery">SELECT * FROM dual</prop>-->
</props>
</property>
</bean>
<bean id="dataSource" class="org.springframework.jdbc.datasource.DriverManagerDataSource">
<property name="driverClassName" value="${JDBC.Driver}"/>
<property name="url" value="${JDBC.ConnectionURL}"/>
<property name="username" value="${JDBC.Username}"/>
<property name="password" value="${JDBC.Password}"/>
</bean>
</beans>
当我运行简单的单元测试时，连接和验证数据库表大约需要150秒。但是当我取消注释c3p0属性时，我在大约90秒后得到以下异常。我想我需要有更多的时间来打开连接，但我无法弄清楚如何做到这一点。
org.springframework.transaction.CannotCreateTransactionException: Could not open JPA EntityManager for transaction; nested exception is javax.persistence.PersistenceException: org.hibernate.exception.GenericJDBCException: Cannot open connection
at org.springframework.orm.jpa.JpaTransactionManager.doBegin(JpaTransactionManager.java:382)
at org.springframework.transaction.support.AbstractPlatformTransactionManager.getTransaction(AbstractPlatformTransactionManager.java:371)
at org.springframework.test.context.transaction.TransactionalTestExecutionListener$TransactionContext.startTransaction(TransactionalTestExecutionListener.java:507)
at org.springframework.test.context.transaction.TransactionalTestExecutionListener.startNewTransaction(TransactionalTestExecutionListener.java:269)
at org.springframework.test.context.transaction.TransactionalTestExecutionListener.beforeTestMethod(TransactionalTestExecutionListener.java:162)
at org.springframework.test.context.TestContextManager.beforeTestMethod(TestContextManager.java:374)
at org.springframework.test.context.junit4.statements.RunBeforeTestMethodCallbacks.evaluate(RunBeforeTestMethodCallbacks.java:73)
at org.springframework.test.context.junit4.statements.RunAfterTestMethodCallbacks.evaluate(RunAfterTestMethodCallbacks.java:82)
at org.springframework.test.context.junit4.statements.SpringRepeat.evaluate(SpringRepeat.java:72)
at org.springframework.test.context.junit4.SpringJUnit4ClassRunner.runChild(SpringJUnit4ClassRunner.java:240)
at org.junit.runners.BlockJUnit4ClassRunner.runChild(BlockJUnit4ClassRunner.java:47)
at org.junit.runners.ParentRunner$3.run(ParentRunner.java:231)
at org.junit.runners.ParentRunner$1.schedule(ParentRunner.java:60)
at org.junit.runners.ParentRunner.runChildren(ParentRunner.java:229)
at org.junit.runners.ParentRunner.access$000(ParentRunner.java:50)
at org.junit.runners.ParentRunner$2.evaluate(ParentRunner.java:222)
at org.springframework.test.context.junit4.statements.RunBeforeTestClassCallbacks.evaluate(RunBeforeTestClassCallbacks.java:61)
at org.springframework.test.context.junit4.statements.RunAfterTestClassCallbacks.evaluate(RunAfterTestClassCallbacks.java:70)
at org.junit.runners.ParentRunner.run(ParentRunner.java:300)
at org.springframework.test.context.junit4.SpringJUnit4ClassRunner.run(SpringJUnit4ClassRunner.java:180)
at org.apache.maven.surefire.junit4.JUnit4TestSet.execute(JUnit4TestSet.java:35)
at org.apache.maven.surefire.junit4.JUnit4Provider.executeTestSet(JUnit4Provider.java:115)
at org.apache.maven.surefire.junit4.JUnit4Provider.invoke(JUnit4Provider.java:97)
at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:39)
at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:25)
at java.lang.reflect.Method.invoke(Method.java:597)
at org.apache.maven.surefire.booter.ProviderFactory$ClassLoaderProxy.invoke(ProviderFactory.java:103)
at $Proxy0.invoke(Unknown Source)
at org.apache.maven.surefire.booter.SurefireStarter.invokeProvider(SurefireStarter.java:150)
at org.apache.maven.surefire.booter.SurefireStarter.runSuitesInProcess(SurefireStarter.java:91)
at org.apache.maven.surefire.booter.ForkedBooter.main(ForkedBooter.java:69)
Caused by: javax.persistence.PersistenceException: org.hibernate.exception.GenericJDBCException: Cannot open connection
at org.hibernate.ejb.AbstractEntityManagerImpl.convert(AbstractEntityManagerImpl.java:1235)
at org.hibernate.ejb.AbstractEntityManagerImpl.convert(AbstractEntityManagerImpl.java:1168)
at org.hibernate.ejb.AbstractEntityManagerImpl.throwPersistenceException(AbstractEntityManagerImpl.java:1245)
at org.hibernate.ejb.TransactionImpl.begin(TransactionImpl.java:63)
at org.springframework.orm.jpa.DefaultJpaDialect.beginTransaction(DefaultJpaDialect.java:70)
at org.springframework.orm.jpa.vendor.HibernateJpaDialect.beginTransaction(HibernateJpaDialect.java:55)
at org.springframework.orm.jpa.JpaTransactionManager.doBegin(JpaTransactionManager.java:332)
... 31 more
Caused by: org.hibernate.exception.GenericJDBCException: Cannot open connection
at org.hibernate.exception.SQLStateConverter.handledNonSpecificException(SQLStateConverter.java:140)
at org.hibernate.exception.SQLStateConverter.convert(SQLStateConverter.java:128)
at org.hibernate.exception.JDBCExceptionHelper.convert(JDBCExceptionHelper.java:66)
at org.hibernate.exception.JDBCExceptionHelper.convert(JDBCExceptionHelper.java:52)
at org.hibernate.jdbc.ConnectionManager.openConnection(ConnectionManager.java:449)
at org.hibernate.jdbc.ConnectionManager.getConnection(ConnectionManager.java:167)
at org.hibernate.jdbc.JDBCContext.connection(JDBCContext.java:142)
at org.hibernate.transaction.JDBCTransaction.begin(JDBCTransaction.java:85)
at org.hibernate.impl.SessionImpl.beginTransaction(SessionImpl.java:1463)
at org.hibernate.ejb.TransactionImpl.begin(TransactionImpl.java:60)
... 34 more
Caused by: java.sql.SQLException: Connections could not be acquired from the underlying database!
at com.mchange.v2.sql.SqlUtils.toSQLException(SqlUtils.java:106)
at com.mchange.v2.c3p0.impl.C3P0PooledConnectionPool.checkoutPooledConnection(C3P0PooledConnectionPool.java:529)
at com.mchange.v2.c3p0.impl.AbstractPoolBackedDataSource.getConnection(AbstractPoolBackedDataSource.java:128)
at org.hibernate.connection.C3P0ConnectionProvider.getConnection(C3P0ConnectionProvider.java:78)
at org.hibernate.jdbc.ConnectionManager.openConnection(ConnectionManager.java:446)
... 39 more
Caused by: com.mchange.v2.resourcepool.CannotAcquireResourceException: A ResourcePool could not acquire a resource from its primary factory or source.
at com.mchange.v2.resourcepool.BasicResourcePool.awaitAvailable(BasicResourcePool.java:1319)
at com.mchange.v2.resourcepool.BasicResourcePool.prelimCheckoutResource(BasicResourcePool.java:557)
at com.mchange.v2.resourcepool.BasicResourcePool.checkoutResource(BasicResourcePool.java:477)
at com.mchange.v2.c3p0.impl.C3P0PooledConnectionPool.checkoutPooledConnection(C3P0PooledConnectionPool.java:525)
... 42 more
答案 0 :(得分：5)
我想出来了。我最终打开了log4j，我看到一个NullPointerException来自JDBC驱动程序......这从来没有被堆叠到我之前看到的异常中，所以根本没有任何根本原因的痕迹。我需要在JPA属性中指定连接参数，如下所示：
<bean id="entityManagerFactory" class="org.springframework.orm.jpa.LocalContainerEntityManagerFactoryBean">
<property name="dataSource" ref="dataSource" />
<property name="persistenceUnitName" value="MagicPersistenceUnit" />
<property name="jpaVendorAdapter" ref="jpaAdapter" />
<property name="jpaDialect">
<bean class="org.springframework.orm.jpa.vendor.HibernateJpaDialect"/>
</property>
<property name="jpaProperties">
<props>
<prop key="hibernate.hbm2ddl.auto">validate</prop>
<prop key="hibernate.dialect">org.hibernate.dialect.Oracle10gDialect</prop>
<prop key="hibernate.connection.provider_class">org.hibernate.connection.C3P0ConnectionProvider</prop>
<prop key="hibernate.connection.driver_class">${JDBC.Driver}</prop>
<prop key="hibernate.connection.url">${JDBC.ConnectionURL}</prop>
<prop key="hibernate.connection.username">${JDBC.Username}</prop>
<prop key="hibernate.connection.password">${JDBC.Password}</prop>
<prop key="hibernate.c3p0.maxSize">1</prop>
<prop key="hibernate.c3p0.minSize">1</prop>
<prop key="hibernate.c3p0.acquireIncrement">1</prop>
<prop key="hibernate.c3p0.idleTestPeriod">300</prop>
<prop key="hibernate.c3p0.maxStatements">0</prop>
<prop key="hibernate.c3p0.timeout">1800</prop>
<prop key="hibernate.c3p0.checkoutTimeout">0</prop>
<prop key="hibernate.c3p0.preferredTestQuery">SELECT * FROM dual</prop>
</props>
</property>
</bean>
我不知道为什么它没有从我给EntityManager的dataSource中选择参数。