来自静态类/接口的 Guice 泛型配置错误

Question

我在尝试连接 guice 时遇到了错误。这是一些重现我所看到的问题的示例代码：

public class GuiceGenerics<K, V> {

    public static interface Foo<K, V> {

    }

    public static class FooImpl<K, V> implements Foo<K, V> {

    }

    public static class FooModule extends PrivateModule {

        @Override
        protected void configure() {
            bind(new TypeLiteral<Foo<String, Integer>>(){}).to(new TypeLiteral<FooImpl<String, Integer>>(){});

            bind(new TypeLiteral<GuiceGenerics<String, Integer>>(){});
            expose(new TypeLiteral<GuiceGenerics<String, Integer>>(){});
        }
    }

    private Foo<K, V> foo;

    @Inject
    public GuiceGenerics(Foo<K, V> foo) {
        this.foo = foo;
    }

    public static void main(String args[]) {
        Injector injector = Guice.createInjector(new FooModule());
        GuiceGenerics<String, Integer> guiceGenerics = injector.getInstance(GuiceGenerics.class);
    }
}

当我运行 main() 时，我得到这个错误：

Exception in thread "main" com.google.inject.ConfigurationException: Guice configuration errors:

1) com.knewton.recommendationservice.retries.GuiceGenerics$Foo<K, V> cannot be used as a key; It is not fully specified.
  at com.knewton.recommendationservice.retries.GuiceGenerics.<init>(GuiceGenerics.java:36)
  while locating com.knewton.recommendationservice.retries.GuiceGenerics

1 error
    at com.google.inject.internal.InjectorImpl.getProvider(InjectorImpl.java:1004)
    at com.google.inject.internal.InjectorImpl.getProvider(InjectorImpl.java:961)
    at com.google.inject.internal.InjectorImpl.getInstance(InjectorImpl.java:1013)
    at com.knewton.recommendationservice.retries.GuiceGenerics.main(GuiceGenerics.java:42)

我感觉我在错误地使用 TypeLiteral，但我无法弄清楚我到底做错了什么。有什么建议吗？

Answer 1

由于类型擦除，您的getInstance() 呼叫无法工作。改为这样做：

GuiceGenerics<String, Integer> guiceGenerics =
        injector.getInstance(new Key<GuiceGenerics<String, Integer>>() { });