You can process JavaScript Object
Notation (JSON) requests and responses with Java™ Architecture for XML Binding (JAXB) annotated
objects and Jackson. Jackson is the default JSON processor in WebSphere® Application Server.
By default, it is included in the JAX-RS runtime environment so you
do not need to configure Jackson.
About this task
This task provides instructions for processing JSON requests
and responses with JAXB annotated objects and Jackson.
Procedure
- Create a resource method. For the resource method
to return JSON content, return an instance of a JAXB class directly
or return a javax.ws.rs.core.Response object with
a JAXB object as the response entity. You must also either add an @Produces("application/json") annotation,
or set the Content-Type header in your Response object to be "application/json".
The following example illustrates simple JSON return methods for the BookList JAXB
class:
@GET
@Produces("application/json")
public BookList getBookList() {
BookList list = /* get a book list */
return list;
}
or@GET
@Produces("application/json")
public javax.ws.rs.core.Response getBookList() {
BookList list = /* get a book list */
return Response.ok(list).type(MediaType.APPLICATION_JSON_TYPE).build();
}
- If you want to return both XML and JSON objects, you can
reuse the same method with minimal modification. You must
specify "application/xml", "application/json",
and "text/xml" in the @Produces annotation.
The following example illustrates a simple JSON return method that
returns a BookList object for the BookList JAXB
class:
@GET
@Produces("application/json", "application/xml", "text/xml")
public BookList getBookList() {
BookList list = /* get a book list */
return list;
}
The following example illustrates a simple JSON return
method that returns a javax.ws.rs.core.Response object
for the BookList JAXB class:@GET
@Produces("application/json", "application/xml", "text/xml")
public javax.ws.rs.core.Response getBookList() {
BookList list = /* get a book list */
return Response.ok(list).build();
}
Content negotiation through the client request's Accept
HTTP header helps determine whether a JSON or XML representation is
returned by the resource method. Read about content negotiation for
more information. By reusing the JAXB annotated objects, you can shorten
the development time to serve both JSON and XML from the same code.
Reusing the same model code can be beneficial if specific JSON or
XML formatted output is not required.If you require specific XML
and JSON output and cannot reuse the same JAXB annotated classes,
one way to solve the problem is to use two different resource methods.
The JSON resource method must be annotated with an @Produces("application/json") annotation
and the XML resource method must be annotated with an @Produces("application/xml",
"text/xml") annotation.
Results
You have returned a JSON representation with JAXB annotated
classes through the Jackson JSON processor.