Shanshan
You have to set de M2_REPO variable in Eclipse (sorry because I forgot to tell you that).
To do that, look at http://www.mkyong.com/maven/how-to-configure-m2_repo-variable-in-eclipse-ide/ and http://www.mkyong.com/maven/where-is-maven-local-repository/
Moreover, don't worry about the "Javadoc for some artifacts is not available." warning.
Regards