Rest annotations

@GET                 import javax.ws.rs.GET;

@Produces         import javax.ws.rs.Produces;

@Path                import javax.ws.rs.Path;

@PathParam      import javax.ws.rs.PathParam;

@QueryParam    import javax.ws.rs.QueryParam;

@POST               import javax.ws.rs.POST;

@Consumes       import javax.ws.rs.Consumes;

@FormParam     import javax.ws.rs.FormParam;

@PUT                 import javax.ws.rs.PUT;

@DELETE            import javax.ws.rs.DELETE;

@GET

Annotate your Get request methods with @GET.    This  annotation is use  for   read only operations . Means    whenever we need  get  data   from any  data source  then @GET annotation going to be used.

  Here is simple  example   of   how it is used .

      import javax.ws.rs.GET;  

import javax.ws.rs.Path;  

import javax.ws.rs.PathParam;  

import javax.ws.rs.core.Response;  

@Path("/hello")  

public class HelloService{  

    @GET  

    @Path("/{param}")  

    public Response getMsg(@PathParam("param") String msg) {  

        String output = "Mukesh" + msg;  

        return Response.status(200).entity(output).build();  

    }  

}  

@Produces

@Produces annotation specifies the type of output method (or web service) will produce.  The @produce   specify   what type of data format is available by the method.

    These are  following  type   data format   the

1. @Produces("text/plain"): for downloading text file.
2. @Produces("image/png"): for downloading png image file.
3. @Produces("application/pdf"): for downloading PDF file.
4. @Produces("application/vnd.ms-excel"): for downloading excel file.
5. @Produces("application/msword"): for downloading ms word file.

1.  @Path("/files")  

public class FileDownloadService {  

    @GET  

    @Path("/txt")  

    @Produces("text/plain")  

    public Response getFile() {  

        // method  code    

    }  

 }  

2.

  @Path("/files")  

public class FileDownloadService {  

    @GET  

    @Path("/txt")  

    @Produces("image/png")  

    public Response getFile() {  

        // method  code    

    }  

 }  

 @Consumes

The @Consumes annotation is used to specify the MIME media types a REST resource can consume.

@Path("/files")  

public class FileUploadService {  

    @POST  

    @Path("/upload")  

    @Consumes(MediaType.MULTIPART_FORM_DATA)  

    public Response uploadFile(  ){

        // Method  code

     }

  }  

@path(“/empcnt”)

public class   Employee_Contact { 

@PUT

@Consumes("application/json")

@Produces("application/json")

@Path("/contactId")

public RestResponse<Contact> update(Contact contact) {

...

}

@Path

@Path annotation used to define  path URL   using   which   client   able to invoke the particular method.  After the @path annotation   we specify   the methods pathparamater.

@GET

@Produces("application/xml")

@Path("xml/{firstName}")

public Contact getXML() {

  // Method code

}

@PathParam

We can bind REST-style URL parameters to method arguments using @PathParam annotation as shown below.

@GET

@Produces("application/xml")

@Path("xml/{firstName}")

public Contact getXML(@PathParam("firstName") String firstName) {

  Contact contact = contactService.findByFirstName(firstName);

  return contac;

}

@GET

@Produces("application/json")

@Path("json/{firstName}")

public Contact getJSON(@PathParam("firstName") String firstName) {

  Contact contact = contactService.findByFirstName(firstName);

  return contact;

}

@QueryParam

Request parameters in query string can be accessed using @QueryParam annotation as shown below. This represent   the parameters  of the  query string of an URL

 @path(“/”)

 Public class  Company {

@GET

@Produces("application/json")

@Path("json/companyList")

public CompanyList getJSON(@QueryParam("start") int start, @QueryParam("limit") int limit) {

  CompanyList list = new CompanyList(companyService.listCompanies(start, limit));

  return list;

   }

}

@POST

Annotate POST request methods with @POST.   This usually   used to posting data in table. This  is not  idempotent .  This means  it  will repetitively add  data  for request. There may chance to add same data multiple time . Post  used to create data means new row in table.

import javax.ws.rs.FormParam;  

import javax.ws.rs.POST;  

import javax.ws.rs.Path;  

import javax.ws.rs.core.Response;  

@Path("/product")  

public class ProductService{  

    @POST  

    @Path("/add")  

    public Response addUser(  

        @FormParam("id") int id,  

        @FormParam("name") String name,  

        @FormParam("price") float price) {  

   

        return Response.status(200)  

            .entity(" Product added successfuly!<br> Id: "+id+"<br> Name: " + name+"<br> Price: "+price)  

            .build();  

    }  

}  

@PUT

Annotate  @PUT  annotation   is  update  the existing  row.   This usually   used to update  data in table. This  is  idempotent .  This means  it not repetitively add  data  for request.

import javax.ws.rs.FormParam;  

import javax.ws.rs.POST;  

import javax.ws.rs.Path;  

import javax.ws.rs.core.Response;  

@Path("/product")  

public class ProductService{  

    @PUT 

    @Path("/add")  

    public Response addUser(  

        @FormParam("id") int id,  

        @FormParam("name") String name,  

        @FormParam("price") float price) {  

   

        return Response.status(200)  

            .entity(" Product added successfuly!<br> Id: "+id+"<br> Name: " + name+"<br> Price: "+price)  

            .build();  

    }  

}  

@FormParam

The REST resources will usually consume XML/JSON for the complete Entity Bean. Sometimes, you may want to read parameters sent in POST requests directly and you can do that using @FormParam annotation. GET Request query parameters can be accessed using @QueryParam annotation

@DELETE

Annotate DELETE request methods with @DELETE.  This  annotation  used  when you want  to delete some  data or content  form your table ot text.

@DELETE

@Produces("application/json")

@Path("{contactId}")

public RestResponse<Contact> delete(@PathParam("contactId") int contactId) {

...

}