In Chapter 9, you learned about many of the concepts of HATEOAS and how to use
JAX-RS to add these principles to your RESTful web services. In this
chapter, you’ll look through two different examples. The first shows you how
to introduce Atom links into your XML documents. The second uses
Link headers to publish state transitions within a
RESTful web service application.
This example is a slight modification of the ex06_1 example introduced in Chapter 19. This example expands the
CustomerResource RESTful web service so that a
client can fetch subsets of the customer database. If a client does a
request in our RESTful application, it will receive a subset list of
customers in XML. Two Atom links are embedded in this document that allow
you to view the next or previous sets of customer data. Example output
<customers> <customer id="3"> ... </customer> <customer id="4"> ... </customer> <link rel="next" href="http://example.com/customers?start=5&size=2" type="application/xml"/> <link rel="previous" href="http://example.com/customers?start=1&size=2" type="application/xml"/> </customers>
previous links are URLs pointing to the same
/customers URL, but they contain URI
query parameters indexing into the customer database.
The first thing you want to look at is the extensions made to the
JAXB model. A new class
Link is added so that you can define Atom links and embed them within ...