Is there any plugin available for Eclipse or Netbeans or any other IDE which can help me generate the hbm.xml by directly reading the schema from the database.
Writing those XMLs seem to be unnecessary waste of time, and feel it should be automated.
For NetBeans, have a look at Using Hibernate in a Web Application.
For Eclipse, use the Hibernate Tools plugin. Here is a tutorial demonstrating how to use its Reverse Engineering feature.
Hibernate Tools includes all sorts of tools for doing hbm and class conversions.