46.4. Using Apache CXF extensions

Overview

Apache CXF provides an extension to the standard JAX-WS injection mechanism that allows developers to replace a sequence of injection annotations with a single annotation. The single annotation is place on a bean containing fields for the data that is extracted using the annotation. For example, if a resource method is expecting a request URI to include three query parameters called id, type, and size, it could use a single @QueryParam annotation to inject all of the parameters into a bean with corresponding fields.
Note
Consider using the @BeanParam annotation instead (available since JAX-RS 2.0). The standardized @BeanParam approach is more flexible than the proprietary Apache CXF extension, and is thus the recommended alternative. For details, see Section 46.2.6, “Injecting Parameters into a Java Bean”.

Supported injection annotations

This extension does not support all of the injection parameters. It only supports the following ones:
  • @PathParam
  • @QueryParam
  • @MatrixParam
  • @FormParam

Syntax

To indicate that an annotation is going to use serial injection into a bean, you need to do two things:
  1. Specify the annotation's parameter as an empty string. For example @PathParam("") specifies that a sequence of URI template variables are to be serialized into a bean.
  2. Ensure that the annotated parameter is a bean with fields that match the values being injected.

Example

Example 46.11, “Injecting query parameters into a bean” shows an example of injecting a number of Query parameters into a bean. The resource method expect the request URI to include two query parameters: type and id. Their values are injected into the corresponding fields of the Monster bean.

Example 46.11. Injecting query parameters into a bean

import javax.ws.rs.QueryParam;
import javax.ws.rs.PathParam;
import javax.ws.rs.POST;
import javax.ws.rs.Path;
...

@Path("/monstersforhire/")
public class MonsterService
{
  ...
  @POST
  public void updateMonster(@QueryParam("") Monster bean)
  {
    ...
  }
  ...
}

public class Monster
{
  String type;
  String id;

  ...
}