jboss 配置 oracle 数据源

in global-ds.xml (same as oracle-ds.xml): <?xml version="1.0" encoding="UTF-8" standalone="no" ?> 
<datasources>
<local-tx-datasource>
  <jndi-name>EFOPool</jndi-name> 
  <connection-url>jdbc:oracle:thin:@erioradev1.erie.ge.com:1521:TSEFDEV2</connection-url> 
  <driver-class>oracle.jdbc.OracleDriver</driver-class> 
  <user-name>APPS</user-name> 
  <password>APPS</password> 
  <exception-sorter-class-name>org.jboss.resource.adapter.jdbc.vendor.OracleExceptionSorter</exception-sorter-class-name> 
  <valid-connection-checker-class-name>org.jboss.resource.adapter.jdbc.vendor.OracleValidConnectionChecker</valid-connection-checker-class-name> 
<metadata>
  <type-mapping>Oracle9i</type-mapping> 
  </metadata>
  </local-tx-datasource>
</datasources>------------------------------------------------------------------------in the jsp file:<%@ page language="java" contentType="text/html;charset=gb2312" pageEncoding="GBK"%>
<%@ page import="java.sql.*,javax.sql.DataSource,javax.naming.InitialContext" %> <h3>测试JBOSS连接Oracle 9    i数据库</h3> 
<h3>Test Oracle Database</h3> <% 
InitialContext ctx = new InitialContext();
DataSource ds = (DataSource) ctx.lookup("java:/EMTPool");
out.println("ds is : "+ds);
%>----------------------------------------------------------------------The Result is "ds is : null";How to resolved it? Thanks a million !