I want to query two table by using getHibernateTemplate().find,like follows:
getHibernateTemplate().find("from test.a a ,test.b b where a.id=b.id and a.c='abc'")

My question is how to extract data from getHibernateTemplate().find statement?

Thanks in advance!

Its depends what You want receive from this query.
Specify "select" clause in this query.
for ex. "select a from ..", and retrieve list of test.a.

Read please also "14.6. The select clause" in "Hibernate Reference Documentation".