之前用Eclipse JEE开发web工程，按照网上的一些说法，配置，发现很麻烦。而且每次project重新remove再加载，配置就丢失了。
根据tomcat使用的经验，尝试如下方法，就可以解决一次配置，所有同workspace的project都可以随时使用jdni了。
确保Eclipse中配置了tomcat runtime的情况下，在Eclipse中创建第一个web工程的时候，他会自动增加一个Tomcat Server工程，来维护一个tomcat容器，供你的工程来使用。
首先看一下project中的tomcat容器项目的列表：
保存如下内容为context.xml，增加到Server项目里Tomcat v5.5 Server at localhost-config里：
<?xml version="1.0" encoding="UTF-8"?>
<!--
Licensed to the Apache Software Foundation (ASF) under one or more
contributor license agreements. See the NOTICE file distributed with
this work for additional information regarding copyright ownership.
The ASF licenses this file to You under the Apache License, Version 2.0
(the "License"); you may not use this file except in compliance with
the License. You may obtain a copy of the License at
http://www.apache.org/licenses/LICENSE-2.0
Unless required by applicable law or agreed to in writing, software
distributed under the License is distributed on an "AS IS" BASIS,
WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
See the License for the specific language governing permissions and
limitations under the License.
-->
<!-- The contents of this file will be loaded for each web application -->
<Context>
<!-- Default set of monitored resources -->
<WatchedResource>WEB-INF/web.xml</WatchedResource>
<!-- Uncomment this to disable session persistence across Tomcat restarts -->
<!--
<Manager pathname="" />
-->
<Resource auth="Container" driverClassName="oracle.jdbc.driver.OracleDriver" maxActive="30" maxIdle="5" maxWait="-1" name="jdbc/db02" password="pass" type="javax.sql.DataSource" url="jdbc:oracle:thin:@192.168.0.2:1521:myEntry" username="user"/>
</Context>
测试一下吧，在这个workspace中新建一个web工程，运行，已经可以正常使用jdbc/db02拿到数据库连接池了。
