1.tomcat的版本，最好不要是安装版的，要解压缩的，不然无法连接数据源。
 
 
 
2.conf》context.xml
         driverClassName="oracle.jdbc.OracleDriver"
         url="jdbc:oracle:thin:@127.0.0.1:1521:orcl"
         username="hotel" password="hotel"
         maxActive="80" maxIdle="20" maxWait="-1"/>
 
 
 
 
3.oracle分页问题
--普通分页
select * from
(select e.*, rownum row_num from emp e where rownum<10)
where row_num>=1;
--分页并排序，两重select
select * from
(select a.*,rownum row_num from (select * from emp e order by empno) a where rownum<10) b
where  b.row_num>=1;