注入名为Guice的单身人士

Question

我有一个简单的POJO:

public class MyPOJO {
    @Inject
    private Fizz fizz;

    private Buzz buzz;

    // rest of class omitted for brevity
}

我想配置我的Guice模块Fizz,它注入了两种类型的es:

1. 一个特殊的全局单例Fizz实例; 和
2. 其他(非特殊)Fizz实例

我想MyPOJO注入特殊/单例实例.所以我修改了我的代码:

public class MyPOJO {
    @Inject @Named("Special-Fizz")
    private Fizz fizz;

    private Buzz buzz;

    // rest of class omitted for brevity
}

然后在我的模块中:

public class MyModule extends AbstractModule {
    @Override
    public void configure() {
        bind(Fizz.class).annotatedWith(
            Names.named("Special-Fizz"))
            .to(Fizz.class);

        // Other bindings here...
    }

    @Provides @Singleton
    private Fizz providesFizz() {
        return new Fizz(true, "Special", 12.0);
    }
}

但是当我尝试单元测试(JUnit 4.10)时:

public class MyTest {
    @Named("Special-Fizz") private Fizz specialFizz;

    @Test
    public void usingNamedShouldInjectSpecialFizz() {
        MyModule mod = new MyModule();
        Injector injector = Guice.createInjector(mod);

        specialFizz = injector.getInstance(Fizz.class);

        Assert.assertTrue(specialFizz != null);
    }
}

这过去了.到现在为止还挺好.但是如果我更改specialFizz字段的名称:

    @Named("Special-Fuzz-This-Shouldnt-Work") private Fizz specialFizz;

并重新进行测试,它仍然通过.为什么？!？我在哪里误入歧途？提前致谢.

Answer 1

很奇怪。如果 Guice 找不到Named它正在注入的绑定，它应该抱怨。不过，我对你的测试有点困惑。不知道有什么injector.inject作用 你的意思是injectMembers？实际获取 POJO 的实例并确保它按您期望的方式工作可能更有意义。也许是这样的：

public class FizzTest {

  public static class MyModule extends AbstractModule {
    @Override
    protected void configure() {
    }

    @Provides
    @Singleton
    @Named("Special-Fizz")
    public Fizz providesFizz() {
      return new Fizz(true);
    }
  }

  public static class Fizz {
    boolean special = false;
    public Fizz() {}
    public Fizz(boolean special) {
      this.special = special;
    }
  }

  public static class MyPOJO {
    @Inject @Named("Special-Fizz")
    private Fizz fizz;

    @Inject
    private Fizz otherFizz;
  }

  @Test
  public void test() {
    MyModule mod = new MyModule();
    Injector injector = Guice.createInjector(mod);

    MyPOJO pojo = injector.getInstance(MyPOJO.class);
    assertTrue(pojo.fizz.special);
    assertTrue(!pojo.otherFizz.special);
  }

}