JAX-RS: URIs and the Path annotations

The @Path annotation identifies the URI path template to which the resource responds and is specified at the class or method level of a resource.

URI path templates are URIs with variables embedded within the URI syntax. These variables are substituted at runtime in order for a resource to respond to a request based on the substituted URI. Variables are denoted by braces ({ and }). eg:

@Path("/users/{username}")

A @Path value isn’t required to have leading or trailing slashes (/). The JAX-RS runtime parses URI path templates the same whether or not they have leading or trailing spaces.

By default, the URI variable must match the regular expression “[^/]+?” This variable may be customized by specifying a different regular expression after the variable name. eg:

 @Path("users/{username: [a-zA-Z][a-zA-Z_0-9]*}")

A URI path template has one or more variables, with each variable name surrounded by braces: { to begin the variable name and } to end it. eg:

@Path("/{name1}/{name2}/")

You consume and use these parameters, add a @javax.ws.rs.PathParam annotation in either the resource constructor or the resource method.

Sample using @PathParam,

@Path("/hello/{username}")
public class HelloResource {
 @GET
 public String helloGet(@javax.ws.rs.PathParam("username") String username) {
  return "[GET] Hello "+username+" from JAX-RS on WebSphere Application server";
 }
}

Client code,

String lsUrl = "http://localhost:9080/RSServer/HelloApp/hello/John";
RestClient client = new RestClient();
Resource resource = client.resource(lsUrl);
ClientResponse result = resource.contentType(MediaType.TEXT_PLAIN).get();
System.out.println(result.getEntity(String.class));

Sample using @MatrixParam,

@Path("/hello")
public class HelloResource {
@GET
public String helloGet(@javax.ws.rs.MatrixParam("username") String username) {
return "[GET] Hello "+username+" from JAX-RS on WebSphere Application server";
}
}

Client code,

String lsUrl = "http://localhost:9080/RSServer/HelloApp/hello;username=John";
RestClient client = new RestClient();
Resource resource = client.resource(lsUrl);
ClientResponse result = resource.contentType(MediaType.TEXT_PLAIN).get();
System.out.println(result.getEntity(String.class));

Sample using @QueryParam,

@Path("/hello")
public class HelloResource {
@GET
public String helloGet(@javax.ws.rs.QueryParam("username") String username) {
return "[GET] Hello "+username+" from JAX-RS on WebSphere Application server";
}
}

Client code,

String lsUrl = "http://localhost:9080/RSServer/HelloApp/hello?username=John";
RestClient client = new RestClient();
Resource resource = client.resource(lsUrl);
ClientResponse result = resource.contentType(MediaType.TEXT_PLAIN).get();
System.out.println(result.getEntity(String.class));
(or)
String lsUrl = "http://localhost:9080/RSServer/HelloApp/hello";
RestClient client = new RestClient();
Resource resource = client.resource(lsUrl);
ClientResponse result = resource.contentType(MediaType.TEXT_PLAIN).queryParam("username", "John").get();
System.out.println(result.getEntity(String.class));

@DefaultValue annotation is used to specify a default value. eg:

@DefaultValue("unknown") @javax.ws.rs.QueryParam("username")

Both @QueryParam and @PathParam can be used only on the following Java types: