JPA 复合主键

<a href="http://www.javaeye.com/problems/6846">http://www.javaeye.com/problems/6846</a>

<a href="http://melin.javaeye.com/blog/197217">http://melin.javaeye.com/blog/197217</a>

<a href="http://www.blogjava.net/alex/archive/2009/05/27/80231.html">http://www.blogjava.net/alex/archive/2009/05/27/80231.html</a>