To create a RESTful web service from an existing database, we simply need to go to File | New in a web application project, then select the Web Services category, and select the RESTful Web Services From Database file type:

In the next step in the wizard, we need to pick a data source and select one or more tables to use to generate our web service. In our example, we will generate a web service for the CUSTOMER table of the sample database included in NetBeans.

Now, we need to enter a package for our web service code.

Then, we need to pick a Resource Package or simply accept the default value of service. It is a good idea to enter a package name that follows standard package naming conventions.

When we click on Finish, our RESTful web service code is generated.