Java Reference
In-Depth Information
}
}
In this example, we inject an instance of
UriInfo
into the
getPicture()
method's
info
parameter. We then use this instance to extract information out of the URI.
@MatrixParam
Instead of injecting and processing
PathSegment
objects to obtain matrix parameter values,
the JAX-RS specification allows you to inject matrix parameter values directly through the
@javax.ws.rs.MatrixParam
annotation. Let's change our
CarResource
example from the
previous section to reflect using this annotation:
@Path
(
"/{make}"
)
public
public class
class
CarResource
CarResource
{
@GET
@Path
(
"/{model}/{year}"
)
@Produces
(
"image/jpeg"
)
public
public
Jpeg
getPicture
(
@PathParam
(
"make"
)
String make
,
@PathParam
(
"model"
)
String model
,
@MatrixParam
(
"color"
)
String color
) {
...
}
Using the
@MatrixParam
annotation shrinks our code and provides a bit more readability.
The only downside of
@MatrixParam
is that sometimes you might have a repeating matrix
parameter that is applied to many different path segments in the URI. For example, what if
color
shows up multiple times in our car service example?
GET
/
mercedes
/
e55
;
color
=
black
/
2006
/
interior
;
color
=
tan
Here, the
color
attribute shows up twice: once with the model and once with the interior.
Using
@MatrixParam("color")
in this case would be ambiguous and we would have to go
back to processing
PathSegments
to obtain this matrix parameter.
@QueryParam
The
@javax.ws.rs.QueryParam
annotation allows you to inject individual URI query para-
meters into your Java parameters. For example, let's say we wanted to query a customer
database and retrieve a subset of all customers in the database. Our URI might look like this:
GET
/
customers
?
start
=
0
&
size
=
10
