困扰无法解决,请教各位大虾：Tomcat5.5配置连接池时的异常错误:org.apache.tomcat.dbcp.dbcp.SQLNestedException:
这两天在搭建一个项目的环境，用的是Tomcat5.5 + Oracle 10.2.0.1 ,在Tomcat里面配置数据源。server.xml 配置文件如下：
<?xml version="1.0" encoding="UTF-8"?>

<Server port="8005" shutdown="SHUTDOWN">

  <!-- Comment these entries out to disable JMX MBeans support used for the 
  administration web application -->
  <Listener className="org.apache.catalina.core.AprLifecycleListener" />
  <Listener className="org.apache.catalina.mbeans.ServerLifecycleListener" />
  <Listener className="org.apache.catalina.mbeans.GlobalResourcesLifecycleListener" />
  <Listener className="org.apache.catalina.storeconfig.StoreConfigLifecycleListener"/>

  <!-- Global JNDI resources -->
  <GlobalNamingResources>

  <Environment name="simpleValue" type="java.lang.Integer" value="30"/>

  <Resource name="UserDatabase" auth="Container"
  type="org.apache.catalina.UserDatabase"
  description="User database that can be updated and saved"
  factory="org.apache.catalina.users.MemoryUserDatabaseFactory"
  pathname="conf/tomcat-users.xml" />

<Resource name="platformDataSource" type="javax.sql.DataSource" password="kaizen" driverClassName="oracle.jdbc.driver.OracleDriver" maxIdle="2" maxWait="5000" username="kaizen" url="jdbc:oracle:thin:@//127.0.0.1:1521/orcl" maxActive="4"/>
   

  </GlobalNamingResources>

  <Service name="Catalina">

  <Connector port="8000" maxHttpHeaderSize="8192"
  maxThreads="150" minSpareThreads="25" maxSpareThreads="75"
  enableLookups="false" redirectPort="8443" acceptCount="100"
  connectionTimeout="20000" disableUploadTimeout="true" URIEncoding='UTF-8' />

  <Connector port="8009" 
  enableLookups="false" redirectPort="8443" protocol="AJP/1.3" />

  <Engine defaultHost="localhost" name="Catalina">
  <Host appBase="webapps" name="localhost">

<Context path="/platform" docBase="D:\city\workspace\crmse\platform" crossContext="true" debug="0" reloadable="true">
<Resource name="platformDataSource" type="javax.sql.DataSource" password="kaizen" driverClassName="oracle.jdbc.driver.OracleDriver" maxIdle="2" maxWait="5000" username="kaizen" url="jdbc:oracle:thin:@//127.0.0.1:1521/orcl" maxActive="4"/>
</Context>
   
</Host>
  <Realm className="org.apache.catalina.realm.UserDatabaseRealm"/>
  </Engine>

  </Service>

</Server>

启动Tomacat 时日志文件报错为：
org.apache.tomcat.dbcp.dbcp.SQLNestedException: Cannot create PoolableConnectionFactory (Io 异常: The Network Adapter could not establish the connection)
at org.apache.tomcat.dbcp.dbcp.BasicDataSource.createDataSource(BasicDataSource.java:1225)
at org.apache.tomcat.dbcp.dbcp.BasicDataSource.getConnection(BasicDataSource.java:880)
at com.sinosoft.sysframework.reference.DBManager.open(DBManager.java:63)