Java Reference
In-Depth Information
As you define the resources for your application, consider the type of data you want to
expose. You may already have a relational database that contains information you want
to expose to users, or you may have static content that does not reside in a database but
does need to be distributed as resources. Using JAX-RS, you can distribute content from
multiple sources. RESTful web services can use various types of input/output formats for
Application
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on page
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, uses XML.
Resources have representations. A resource representation is the content in the HTTP
message that is sent to, or returned from, the resource using the URI. Each representation
a resource supports has a corresponding media type. For example, if a resource is going
to return content formatted as XML, you can use
application/xml
as the associated
media type in the HTTP message. Depending on the requirements of your application,
resources can return representations in a preferred single format or in multiple formats.
JAX-RS provides
@Consumes
and
@Produces
annotations to declare the media types
that are acceptable for a resource method to read and write.
JAX-RS also maps Java types to and from resource representations using entity providers.
A
MessageBodyReader
entity provider reads a request entity and deserializes the re-
quest entity into a Java type. A
MessageBodyWriter
entity provider serializes from a
Java type into a response entity. For example, if a
String
value is used as the request en-
tity parameter, the
MessageBodyReader
entity provider deserializes the request body
into a new
String
. If a JAXB type is used as the return type on a resource method, the
MessageBodyWriter
serializes the JAXB object into a response body.
By default, the JAX-RS runtime environment attempts to create and use a default
JAXBContext
class for JAXB classes. However, if the default
JAXBContext
class is
not suitable, then you can supply a
JAXBContext
class for the application using a JAX-
RS
ContextResolver
provider interface.
The following sections explain how to use JAXB with JAX-RS resource methods.
Using Java Objects to Model Your Data
If you do not have an XML schema definition for the data you want to expose, you can
model your data as Java classes, add JAXB annotations to these classes, and use JAXB to
generate an XML schema for your data. For example, if the data you want to expose is a
collection of products and each product has an ID, a name, a description, and a price, you
can model it as a Java class as follows:
