how to write a webservice that accepts XML document?

Write a webservice that accepts the following XML document as the payload:

IMPORT

CUSTOMSWAREIE

71Q0019681

DUB

G0779837

The webservice should respond with a status code which is based on parsing the contents of the XML payload

a. If the XML document is given here is passed then return a status of ‘0’ – which means the document was structured correctly.

b. If the Declararation’s Command <> ‘DEFAULT’ then return ‘-1’ – which means invalid command specified.

c. If the SiteID <> ‘DUB’ then return ‘-2’ – invalid Site specified.