RequestScoped bean CDI上的HttpServletRequest注入

Question

@RequestScoped
public class CurrentTransaction {

    private String user;
    private String token;

    @PersistenceContext(name="mysql")
    protected EntityManager em;

    @Inject HttpServletRequest request;

    public CurrentTransaction() {
        this.user = request.getHeader("user");
        this.token = request.getHeader("token");
    }

    //getters and setters ...
}

@Stateless
@Path("/areas")
public class AreasEndpoint {

   @PersistenceContext(unitName = "mysql")
   protected EntityManager em;

   @Inject
   protected CurrentTransaction current_user_service;

    @POST
    @Path("postman")
    @Consumes(MediaType.APPLICATION_JSON)
    @Produces(MediaType.APPLICATION_JSON)
    @Authentication
    public Response create(AreaRequest request) {

        if (this.current_user_service.getUser() == null) {
            System.out.println("Go!!!");
            return Response.status(Status.FORBIDDEN).build();
        } else {
            System.out.println("---- user: " + this.current_user_service.getUser());
            System.out.println("---- token: " + this.current_user_service.getToken());
        }
    }

    // ...
}

CDI到达以执行CurrentTransaction类的构造函数。但是，HttpServletRequest请求字段未初始化（注入）。

我做错了什么？

Answer 1

关于这个问题的一个最新答案--可能对其他读者有用：CDI中的依赖注入是按照以下顺序完成的：

1. 调用构造函数
2. 字段被注入
调用
3. @PostConstruct带注释的方法

最后一点是您想要进一步初始化的地方,需要对注入的字段进行访问：

@Inject HttpServletRequest request;

public CurrentTransaction() {
    // field injection has not yet taken place here
}

@PostConstruct
public void init() {
    // the injected request is now available
    this.user = request.getHeader("user");
    this.token = request.getHeader("token");
}