How to get all dependecy in a mojo ?

[陈思淼]

My mojo extends AbstractWarMojo, I want to get all the Project's
dependencies including the transitive denpendecies. So i config the
MavenProject in my mojo like thsi:
>
>  /**
>
     * The maven project.
>
     *
>
     * @parameter expression="${project}"
>
     * @required
>
     * @readonly
>
     */
>
    private MavenProject project;

project.getArtifacts() is a empty collection. I saw war plugin and them get
all the war's dependencies in this way? who can tell me how to get all
dependecy in a mojo ?
Thank you.