@IocBean
public abstract class A {
public void aa() {
System.out.println(111);
bb();
}
public abstract void bb();
}

@IocBean
public class B extends A{
@Override
public void bb() {
System.out.println(222);
}
}

public class Controller {
@Inject("refer:b")
private B b;
@At("/listaa")
@Ok("json")
public String listaa() {
b.aa();
return "123";
}
}

问题：注入的b为null怎么解决？