replace dataSource bean in the runtime with h2 datasource

i'm working on a test framework. I want to replace a datasource bean from mysql to h2 (that didn't configured in xml) when some cases are specified to use h2. Some cases are still using mysql, so i can't to modify the datasource config directly.Only one datasource configured in spring xml (no h2 datasource configured)

Is there any way to do this? replace the datasource bean in the sqlmapclient(ibatis) in the runtime?