oracle在tomcat中的配置：

?

 <Context path="/DatabaseTest" docBase="/DatabaseTest"   reloadable="false" crossContext="true">		 
    <Resource   name="jdbc/oracle"   auth="Container"   type="javax.sql.DataSource"  
     maxActive="4"   maxIdle="2"   maxWait="10000"  removeAbandoned="true" removeAbandonedTimeout="60" logAbandoned="true"
     username="xxxx"   password="xxxx"  
     driverClassName="oracle.jdbc.OracleDriver"  
     url="jdbc:oracle:thin:@10.10.10.33:15210:orcl"/>	
 </Context>

?sql server在tomcat中的配置：

  <Context path="/DatabaseTest" docBase="/DatabaseTest"  reloadable="false" crossContext="true">		 
   <Resource   name="jdbc/sqlserver"   auth="Container"              type="javax.sql.DataSource"  maxActive="10"   maxIdle="2"   maxWait="10000"  removeAbandoned="true" removeAbandonedTimeout="60" logAbandoned="true"
 username="xxx"   password="xxx"  driverClassName="net.sourceforge.jtds.jdbc.Driver"  url="jdbc:jtds:sqlserver://10.10.10.250:1433;DatabaseName=xxx"/>
 </Context>

?mysql 在tomcat的配置：

  <Context path="/DatabaseTest" docBase="/DatabaseTest"  reloadable="false" crossContext="true">		 
		<Resource name="jdbc/mysql"   auth="Container"  type="javax.sql.DataSource"  
		maxActive="5"   maxIdle="2"   maxWait="10000"   removeAbandoned="true" removeAbandonedTimeout="60" logAbandoned="true" 
		driverClassName="com.mysql.jdbc.Driver" 
		url="jdbc:mysql://localhost/lpm?user=root&amp;password=&amp;characterEncoding=UTF-8" /> 
 </Context>

??==================================================================

要获取数据库连接可以在src下新建一个conf.property:

ORCL_CONNECTION=java:comp/env/jdbc/oracle
SQL_CONNECTION=java:comp/env/jdbc/sqlserver
MYSL_CONNECTION=java:comp/env/jdbc/mysql

?然后（获取连接后，要记得自己调用下close()方法关闭连接）：

public class DBConn {
	private static Logger log  = Logger.getLogger(DBConn.class.getName());
	private static InitialContext context  = null;
	private static DataSource sql_datas = null;
	private static DataSource orcl_datas = null;
	private static DataSource mysql_datas = null;
	private static String sql_conn = null;
	private static String orcl_conn = null;
	private static String mysql_conn = null;
	static
	{
		sql_conn = GetCfg.getValue("SQL_CONNECTION");
		orcl_conn = GetCfg.getValue("ORCL_CONNECTION");
		mysql_conn = GetCfg.getValue("MYSL_CONNECTION");
		log.info("sql_conn:"+sql_conn);
		log.info("orcl_conn:"+orcl_conn);
		log.info("mysql_conn:"+mysql_conn);
		
		try {
			context = new InitialContext();
		} catch (NamingException e) {
			// TODO Auto-generated catch block
			e.printStackTrace();
		} 
	}
	
	public static Connection getOrlConn()
	{
		Connection con = null;
		try
		{				
			if(null == context)
			{
				log.error("getConn NO_CONTEXT_FOUND");
				return null;
			}
 			if(null == orcl_datas )
			{
 				orcl_datas = (DataSource)context.lookup(orcl_conn);
				if(null == orcl_datas)
				{
					log.error("getConn lookup fail  orcl_conn" + orcl_conn);
					return null;
				}				
			}
			con = orcl_datas.getConnection();
		}
		catch (Exception e) {
			// TODO: handle exception
			e.printStackTrace();
			log.error("getConn exception orcl_conn="+orcl_conn);
		}
		return con;	
	}
	public static Connection getSqlConn()
	{
		Connection con