Export WordPress from one domain to another domain

Question

From one domain (foo.com), select export as WXR and import to (bar.com), also I manually uploaded wp-contents to the new location.

Everything is working, except the the images in the blog post still using the old domain.

1. How to solve it?
2. I have tried to upload into wp.com and they can auto update the images' location, but this does not work for self-hosted wordpress?

Thanks.