基于SSH的项目的连接oracle数据库报Cannot create PoolableConnectionFactory 错误，请大神帮看看
applicationContext.xml中配置数据源代码：
<bean id="dataSource" class="org.apache.commons.dbcp.BasicDataSource">
<property name="driverClassName" value="oracle.jdbc.driver.OracleDriver">
</property>
<property name="url" value="jdbc:oracle:thin:@localhost:1521:ORCL">
</property>
<property name="username" value="system"></property>
<property name="password" value="orcl"></property>
</bean>
发布后在网页输入信息提交后就报错：
org.springframework.jdbc.UncategorizedSQLException: Hibernate operation: Cannot open connection; uncategorized SQLException for SQL [???]; SQL state [null]; error code [0]; Cannot create PoolableConnectionFactory (Io 异常: The Network Adapter could not establish the connection); nested exception is org.apache.commons.dbcp.SQLNestedException: Cannot create PoolableConnectionFactory (Io 异常: The Network Adapter could not establish the connection)
org.springframework.jdbc.support.AbstractFallbackSQLExceptionTranslator.translate(AbstractFallbackSQLExceptionTranslator.java:83)
org.springframework.jdbc.support.AbstractFallbackSQLExceptionTranslator.translate(AbstractFallbackSQLExceptionTranslator.java:80)
org.springframework.jdbc.support.AbstractFallbackSQLExceptionTranslator.translate(AbstractFallbackSQLExceptionTranslator.java:80)
org.springframework.orm.hibernate3.HibernateAccessor.convertJdbcAccessException(HibernateAccessor.java:424)
org.springframework.orm.hibernate3.HibernateAccessor.convertHibernateAccessException(HibernateAccessor.java:410)
org.springframework.orm.hibernate3.HibernateTemplate.doExecute(HibernateTemplate.java:424)
org.springframework.orm.hibernate3.HibernateTemplate.executeWithNativeSession(HibernateTemplate.java:374)
org.springframework.orm.hibernate3.HibernateTemplate.find(HibernateTemplate.java:921)
org.springframework.orm.hibernate3.HibernateTemplate.find(HibernateTemplate.java:913)

root cause 

org.apache.commons.dbcp.SQLNestedException: Cannot create PoolableConnectionFactory (Io 异常: The Network Adapter could not establish the connection)
org.apache.commons.dbcp.BasicDataSource.createDataSource(BasicDataSource.java:1225)
org.apache.commons.dbcp.BasicDataSource.getConnection(BasicDataSource.java:880)
org.springframework.orm.hibernate3.LocalDataSourceConnectionProvider.getConnection(LocalDataSourceConnectionProvider.java:82)
org.hibernate.jdbc.ConnectionManager.openConnection(ConnectionManager.java:423)
org.hibernate.jdbc.ConnectionManager.getConnection(ConnectionManager.java:144)
org.hibernate.jdbc.AbstractBatcher.prepareQueryStatement(AbstractBatcher.java:139)
org.hibernate.loader.Loader.prepareQueryStatement(Loader.java:1547)
org.hibernate.loader.Loader.doQuery(Loader.java:673)
org.hibernate.loader.Loader.doQueryAndInitializeNonLazyCollections(Loader.java:236)
org.hibernate.loader.Loader.doList(Loader.java:2220)
org.hibernate.l