如何创建2个类实例注入不同类的依赖项实现（通过guice）？

1 回答

• 2

  像这样的东西？

  public class GuiceDependencyExample {
  
    static class DBManager {}
    static class DBManagerVendor1 extends DBManager {}
    static class DBManagerVendor2 extends DBManager {}
    static interface Consumer {
      DBManager getDbManager();
    }
  
    static @Retention(RetentionPolicy.RUNTIME) @BindingAnnotation @interface DBManager1 {}
    static @Retention(RetentionPolicy.RUNTIME) @BindingAnnotation @interface DBManager2 {}
  
    static class ConsumerImpl  implements Consumer {
      DBManager  m_dbm;
      @Inject
      public ConsumerImpl  (DBManager dbm) { m_dbm = dbm; }
  
      public DBManager getDbManager() { return m_dbm; }
    }
  
    static abstract class ConsumerModule extends PrivateModule {
      private final Class<? extends Annotation> annotation;
  
      ConsumerModule(Class<? extends Annotation> annotation) {
        this.annotation = annotation;
      }
  
      @Override 
      protected void configure() {
        bind(Consumer.class).annotatedWith(annotation).to(ConsumerImpl.class);
        expose(Consumer.class).annotatedWith(annotation);
        bindDbManager();
      }
  
      abstract void bindDbManager();
    }
  
    static class Client {
      @DBManager1
      @Inject
      Consumer consumer1;
  
      @DBManager2
      @Inject
      Consumer consumer2;
    }
  
    @Test
    public void test() {
      Injector i = Guice.createInjector(
          new ConsumerModule(DBManager1.class) {
            @Override void bindDbManager() {
              bind(DBManager.class).toInstance(new DBManagerVendor1());
            }
          },
          new ConsumerModule(DBManager2.class) {
            @Override void bindDbManager() {
              bind(DBManager.class).toInstance(new DBManagerVendor2());
            }
          });
      Client client = i.getInstance(Client.class);
      assertTrue(client.consumer1.getDbManager() instanceof DBManagerVendor1);
      assertTrue(client.consumer2.getDbManager() instanceof DBManagerVendor2);
    }
  

  回复于 2024-04-19T21:21:44+08:00