Question

我想为注入的字段使用类的泛型参数，但是guice会抱怨未绑定的键。是否可以在Test2中注入该字段？

示例：

public static class Test1<T1> {
    }

    public static class Test2<T2> {
        @Inject
        public Test1<T2> test;
    }

    public static void main(String[] args) throws Exception {
        Injector injector = Jsr250.createInjector(Stage.PRODUCTION, new TestModule());
        Test2<String> test = injector.getInstance(Key.get(new TypeLiteral<Test2<String>>(){}));
    }

    private static class TestModule extends AbstractModule {
        @Override
        protected void configure() {
            bind(new TypeLiteral<Test1<String>>(){}).toInstance(new Test1<String>());
            bind(new TypeLiteral<Test2<String>>(){}).toInstance(new Test2<String>());
        }
    }

Answer 1

嗯，这对java泛型来说太过分了。即使没有注入，您的代码也无法运行，因为Test1<T2>无法匹配Test1<String>。您应该考虑不同的方法，尝试使用Annotation binding，如：

public static class Test2 {
        @Inject @Named("T2")
        public Test1<someGenericInterface> test;
    }

bind(new TypeLiteral<Test1<someGenericInterface>>(){}).annotatedWith(Names.named("T2")).toInstance(new Test1<T2>()); //T2 implements someGenericInterface
bind(new TypeLiteral<Test1<someGenericInterface>>(){}).annotatedWith(Names.named("T1")).toInstance(new Test1<T1>()); //T1 implements someGenericInterface

或实施特定的提供商Provider bindings或使用MapBinder

Google Guice - 使用generic作为注入字段的参数

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