create datasource in tomcat 8
<Host name="localhost" debug="0" appBase="webapps" unpackWARs="true" autoDeploy="false">
<Context path="" docBase="../confluence" debug="0" reloadable="true">
<!-- Logger is deprecated in Tomcat 5.5. Logging configuration for Confluence is specified in confluence/WEB-INF/classes/log4j.properties -->
<!-- If you're using Confluence 5.7 or below; change maxTotal to maxActive -->
<Resource
name="jdbc/confluence"
auth="Container"
type="javax.sql.DataSource"
driverClassName="oracle.jdbc.OracleDriver"
url="jdbc:oracle:thin:@hostname:port:sid"
username="<username>"
password="<password>"
connectionProperties="SetBigStringTryClob=true"
accessToUnderlyingConnectionAllowed="true"
maxTotal="25"
maxIdle="10"
maxWaitMillis="10000"
/>
<Manager pathname="" />
</Context>
</Host>