ORA-12505, TNS:listener does not currently know of SID given in connect descriptor

先把错误给贴出来：

ERROR [main] org.hibernate.util.JDBCExceptionReporter     - Cannot create PoolableConnectionFactory (Listener refused the connection with the following error:
ORA-12505, TNS:listener does not currently know of SID given in connect descriptor
)
WARN  [main]     org.hibernate.cfg.SettingsFactory     - Could not obtain connection metadata
org.apache.commons.dbcp.SQLNestedException: Cannot create PoolableConnectionFactory (Listener refused the connection with the following error:
ORA-12505, TNS:listener does not currently know of SID given in connect descriptor
)
at org.apache.commons.dbcp.BasicDataSource.createDataSource(BasicDataSource.java:855)
at org.apache.commons.dbcp.BasicDataSource.getConnection(BasicDataSource.java:540)
at org.springframework.orm.hibernate3.LocalDataSourceConnectionProvider.getConnection(LocalDataSourceConnectionProvider.java:81)
at org.hibernate.cfg.SettingsFactory.buildSettings(SettingsFactory.java:72)
at org.hibernate.cfg.Configuration.buildSettings(Configuration.java:1463)
at org.hibernate.cfg.Configuration.buildSessionFactory(Configuration.java:1004)
at org.springframework.orm.hibernate3.LocalSessionFactoryBean.newSessionFactory(LocalSessionFactoryBean.java:805)
at org.springframework.orm.hibernate3.LocalSessionFactoryBean.buildSessionFactory(LocalSessionFactoryBean.java:745)
at org.springframework.orm.hibernate3.AbstractSessionFactoryBean.afterPropertiesSet(AbstractSessionFactoryBean.java:134)
at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.invokeInitMethods(AbstractAutowireCapableBeanFactory.java:1201)
at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.initializeBean(AbstractAutowireCapableBeanFactory.java:1171)
at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.createBean(AbstractAutowireCapableBeanFactory.java:425)
at org.springframework.beans.factory.support.AbstractBeanFactory$1.getObject(AbstractBeanFactory.java:251)
at org.springframework.beans.factory.support.DefaultSingletonBeanRegistry.getSingleton(DefaultSingletonBeanRegistry.java:156)
at org.springframework.beans.factory.support.AbstractBeanFactory.getBean(AbstractBeanFactory.java:248)
at org.springframework.beans.factory.support.AbstractBeanFactory.getBean(AbstractBeanFactory.java:160)
at org.springframework.beans.factory.support.DefaultListableBeanFactory.preInstantiateSingletons(DefaultListableBeanFactory.java:284)
at org.springframework.context.support.AbstractApplicationContext.refresh(AbstractApplicationContext.java:352)
at org.springframework.web.struts.ContextLoaderPlugIn.createWebApplicationContext(ContextLoaderPlugIn.java:354)
at org.springframework.web.struts.ContextLoaderPlugIn.initWebApplicationContext(ContextLoaderPlugIn.java:295)
at org.springframework.web.struts.ContextLoaderPlugIn.init(ContextLoaderPlugIn.java:225)
at org.apache.struts.action.ActionServlet.initModulePlugIns(ActionServlet.java:869)
at org.apache.struts.action.ActionServlet.init(ActionServlet.java:336)
at javax.servlet.GenericServlet.init(GenericServlet.java:212)
at org.apache.catalina.core.StandardWrapper.loadServlet(StandardWrapper.java:1173)
at org.apache.catalina.core.StandardWrapper.load(StandardWrapper.java:993)
at org.apache.catalina.core.StandardContext.loadOnStartup(StandardContext.java:4149)
at org.apache.catalina.core.StandardContext.start(StandardContext.java:4458)
at org.apache.catalina.core.ContainerBase.addChildInternal(ContainerBase.java:791)
at org.apache.catalina.core.ContainerBase.addChild(ContainerBase.java:771)
at org.apache.catalina.core.StandardHost.addChild(StandardHost.java:526)
at org.apache.catalina.startup.HostConfig.deployDirectory(HostConfig.java:987)
at org.apache.catalina.startup.HostConfig.deployDirectories(HostConfig.java:909)
at org.apache.catalina.startup.HostConfig.deployApps(HostConfig.java:495)
at org.apache.catalina.startup.HostConfig.start(HostConfig.java:1206)
at org.apache.catalina.startup.HostConfig.lifecycleEvent(HostConfig.java:314)
at org.apache.catalina.util.LifecycleSupport.fireLifecycleEvent(LifecycleSupport.java:119)
at org.apache.catalina.core.ContainerBase.start(ContainerBase.java:1053)
at org.apache.catalina.core.StandardHost.start(StandardHost.java:722)
at org.apache.catalina.core.ContainerBase.start(ContainerBase.java:1045)
at org.apache.catalina.core.StandardEngine.start(StandardEngine.java:443)
at org.apache.catalina.core.StandardService.start(StandardService.java:516)
at org.apache.catalina.core.StandardServer.start(StandardServer.java:710)
at org.apache.catalina.startup.Catalina.start(Catalina.java:583)
at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
at sun.reflect.NativeMethodAccessorImpl.invoke(Unknown Source)
at sun.reflect.DelegatingMethodAccessorImpl.invoke(Unknown Source)
at java.lang.reflect.Method.invoke(Unknown Source)
at org.apache.catalina.startup.Bootstrap.start(Bootstrap.java:288)
at org.apache.catalina.startup.Bootstrap.main(Bootstrap.java:413)
Caused by: java.sql.SQLException: Listener refused the connection with the following error:
ORA-12505, TNS:listener does not currently know of SID given in connect descriptor
 
at oracle.jdbc.driver.DatabaseError.throwSqlException(DatabaseError.java:112)
at oracle.jdbc.driver.DatabaseError.throwSqlException(DatabaseError.java:262)
at oracle.jdbc.driver.T4CConnection.logon(T4CConnection.java:388)
at oracle.jdbc.driver.PhysicalConnection.<init>(PhysicalConnection.java:453)
at oracle.jdbc.driver.T4CConnection.<init>(T4CConnection.java:164)
at oracle.jdbc.driver.T4CDriverExtension.getConnection(T4CDriverExtension.java:34)
at oracle.jdbc.driver.OracleDriver.connect(OracleDriver.java:753)
at org.apache.commons.dbcp.DriverConnectionFactory.createConnection(DriverConnectionFactory.java:37)
at org.apache.commons.dbcp.PoolableConnectionFactory.makeObject(PoolableConnectionFactory.java:290)
at org.apache.commons.dbcp.BasicDataSource.validateConnectionFactory(BasicDataSource.java:877)
at org.apache.commons.dbcp.BasicDataSource.createDataSource(BasicDataSource.java:851)
... 49 more

我的项目是导入到myeclipse中的，修该了数据库连接地址，但还是报错，监听器不识别sid，或着是监听器不能用户客户端连接。

在网上搜了好多解决问题的办法，都进行了实验，始终没有成功。

最后才发现问题所在：

数据库连接地址虽然修改了，但是myeclipse没有自动编译，WebRoot/WEB-INF/classes中数据库连接的配置文件没有更改。

项目jdk是1.6，我myeclipse中jdk是1.5，我再myeclipse中把jdk设置成了1.5，但是忘记删除原来的1.6版本jdk了，myeclipse还是用1.6进行编译的，所以在修改过数据库连接地址后，classes中的地址并没有被修改。

如果遇到类似的问题，先检查数据库连接是否正确，再看oracle服务是否启动，其次看oracle中listener.ora和tnsnames.ora是否正确，然后检查processes和sessions的大小是否正确，最后实在没办法了，可以试一下我的这种办法。