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Most used JAX-RS 2.0 annotations

Collection of most-used JAX-RS annontations:

Annotation Usage
@Path('<resourcePath>') specifies the relative path of the resource
client uses this relative path to invoke the service
For example it'll be base URL + /resourcePath
https://172.20.126.118:9101/rest/api/bookmarks
https://172.20.126.118:9101/rest/api/bookmarks/1234

To build something like above your resource class should be as follows:
@Path("/bookmarks")
public class BookmarksResource{

 @Path("{bookmarkId}")
 @GET
 public Response getBookmarkById(@PathParam("bookmarkId") Long bookmarkId){
  //get bookmark by id from DB and build response and return
 }

 //invoked when you client uses /bookmarks
 @GET
 public Response getBookmarks(){
  // return all bookmarks
 }
}
@GET Method using the annotation will handle the HTTP GET requests matching
on this resource path

@Path("{bookmarkId}")
@GET
public Response getBookmarkById(@PathParam("bookmarkId") Long bookmarkId){
  //get bookmark by id from DB and build response and return
}
@POST Method using the annotation will handle the HTTP POST requests matching
on this resource path
 @POST
 @Path("/bookmark")
 public Response createBookmark(Bookmark bookmark){
  //create bookmark in DB
 }
@PUT Method using the annotation will handle the HTTP PUT requests matching
on this resource path
 @PUT
 @Path("{bookmarkId}")
 public Response updateBookmark(@PathParam("bookmarkId") Long bookmarkId, Bookmark bookmark){
  //save the updated details using bookmarkId
 }
@DELETE Method using the annotation will handle the HTTP DELETE requests matching
on this resource path
 @DELETE
 @Path("{bookmarkId}")
 public Response deleteBookmark(@PathParam("bookmarkId") Long bookmarkId){
  //delete the bookmark using id and send response message of success/ failure
 }
@HEAD HEAD method is similar to any GET request, except that the server skips the entity-body in your response
and sends only headers information. Following is a HEAD request made to BookmarksResource we built for GET. Notice the way server sent only headers info and completely removed the body
@OPTIONS  This method is used to find out what HTTP methods and other options are available on this resource in server.
@CONNECT  I have never used this in my application and just to be aware it is used by the client to establish
a network connection to a web server over HTTP.
@TRACE This is also one of the less used methods it is used for debugging the request along the path.
@Produces(MediaType.<returnType>) specifies what type of data is returned from the service to the client.

Eg:
@Produces(MediaType.TEXT_XML)
@Produces(MediaType.TEXT_HTML)
@Produces(MediaType.TEXT_PLAIN)
@Produces(MediaType.APPLICATION_JSON)
@GET
@Produces(MediaType.APPLICATION_JSON)
public Response getBookmarks(){
  // return all bookmarks
 }
@Consumes(MediaType.<acceptedType>) specifies the type of data service accepts to process from the client.
@POST
@Path("/bookmark")
@Consumes(MediaType.APPLICATION_JSON)
public Response createBookmark(Bookmark bookmark){
  //create bookmark in DB
}
@PathParam("<paramName>") used to map the path variable to method parameter.
As below the bookmarkId provided in URI path will be mapped to the parameter of the method.
@PUT
@Path("{bookmarkId}")
public Response updateBookmark(@PathParam("bookmarkId") Long bookmarkId, Bookmark bookmark){
      //The bookmarkId will be 1234 as provided in the URL path
      //save the updated details using bookmarkId
}
@QueryParam("<paramName>") Among multiple ways of passing parameters in request query parameters is one of the most used. As other param mappers @QueryParam is also used to bind the query parameters to method parameters however these params will be separated by '?' in the URI as in below.

https://localhost:9101/rest/api/bookmarks?category=java

@GET
public Response getBookmarksByCategory(@QueryParam("category") String category){
  // return all bookmarks filtered by category
}
@MatrixParam Matrix parameters are a set of name-value in URI path which are separated by ";"
The same URI above with a matrix parameter would be:

https://localhost:9101/rest/api/bookmarks;category=java

and it can be accessed as below:
@GET
public Response getBookmarksByCategory(@MatrixParam("category") String category){
  // return all bookmarks filtered by category
}
@HeaderParam This can be used when you want to bind the request header value to a resource method parameter.
Eg: May be when you want to track analytics by browser you can access the user-agent in http header which gives the browser info.
@GET
@Path("/whoHitMe")
public Response whoHitMe(@HeaderParam("user-agent") String userAgent){
  return Response.status(200)
   .entity("invokedBy --> " + userAgent)
   .build();
}
@CookieParam If you have any information stored in cookie you can extract and bind to method parameter using this annotation.

@GET
@Path("/whoAmI")
public Response whoAmI(@CookieParam("samId") String samId){
  return Response.status(200)
   .entity("I am --> " + samId)
   .build();
}

Happy Coding ✌

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