Tomcat Connection Data Source issue

Data | data Source | problem

Toss for hours.

Finally connected, now to the end. I used the tomcat50.28. Connect MySQL database!

1, first configure the data source under Tomcat Admin!

2, add <resource-ref> under Web.xml
<description>northwind connection</description>
<res-ref-name>jdbc/Northwind</res-ref-name>
<res-type>javax.sql.DataSource</res-type>
<res-auth>Container</res-auth>
</resource-ref>

3, in the Conf directory under the Catalina under the localhost of the file's XML configuration plus <resourcelink name= "jdbc/root" global= "Jdbc/root" type= " Javax.sql.DataSourcer "/>

Where Jdbc/root is the data source name