一、<data-sources>元素：                                                                                                                                  <data-sources>可包括多个<data-source>元素，<data-source>元素配置形式如下：                                

  <data-source type="org.apache.commons.dbcp.BasicDataSource">                                                       <set-property property="autoCommit" value="true"/>

<set-property property="driverClass" value="......"/>

<set-property property="url" value="......"/>

<set-property property="maxCount" value="10"/>

<set-property property="minCount" value="2"/>

<set-property property="user" value="....."/>

<set-property property="password" value="......"/>

</data-source>

配置了数据源后，可以通过以下代码访问数据源：

public ActionForward
       execute(ActionMapping mapping,
               ActionForm form,
               HttpServletRequest request,
               HttpServletResponse response) throws Exception
{
javax.sql.DataSource dataSource;
java.sql.Connection myConnection;
try {
  dataSource = getDataSource(request);
  myConnection = dataSource.getConnection();
  // do what you wish with myConnection
} catch (SQLException sqle) {
    getServlet().log("Connection.process", sqle);
} finally {
    //enclose this in a finally block to make
    //sure the connection is closed
    try {
       myConnection.close();
    } catch (SQLException e) {
       getServlet().log("Connection.close", e);
    }
   }
}

当在配置文件中声明多个数据源时，此时需要为每一个数据源分配一个唯一的key 值，通过该值来访问特定的数据源。例如：

data-sources>
   <data-source key="A" type="org.apache.commons.dbcp.BasicDataSource">
      ... properties as before ...
   </data-source>
   <data-source key="B" type="org.apache.commons.dbcp.BasicDataSource">
      ... properties as before ...
   </data-source>
   ...
</data-sources>

此时可通过如下代码访问数据源：
dataSourceA = getDataSource(request, "A");
      dataSourceB = getDataSource(request, "B");