Question

标题描述了我的问题。

E.g。

public class EntryDAOModule extends AbstractModule {

    @Override
    protected void configure() {
        bind(EntryDAO.class).to(EntryDTOMongoImpl.class); // what should this be?       
    }
}

如图所示，.to的参数应该是什么，如下所示：

public class GenericDAOMongoImpl<T, K extends Serializable> extends BasicDAO<T, K> {
    public GenericDAOMongoImpl(Class<T> entityClass) throws UnknownHostException {
        super(entityClass, ConnectionManager.getDataStore());
    }
}

public class EntryDAOMongoImpl extends GenericDAOMongoImpl<EntryDTOMongoImpl, ObjectId> implements EntryDAO<EntryDTOMongoImpl> {
    private static final Logger logger = Logger.getLogger(EntryDAOMongoImpl.class);

    @Inject
    public EntryDAOMongoImpl(Class<EntryDTOMongoImpl> entityClass) throws UnknownHostException {
        super(entityClass);
    }
    ...
}

如何实例化EntryDAOMongoImpl类，如下所示：

Injector injector = Guice.createInjector(new EntryDAOModule());
this.entryDAO = injector.getInstance(EntryDAO.class); // what should this be?

Answer 1

这里你需要的是创建一个工厂。使用辅助注射可以帮助你。

您可以看到我的previous post regarding assisted injection

但这是您案件的确切解决方案：

EntryDAOMongoImpl：

public class EntryDAOMongoImpl extends GenericDAOMongoImpl<EntryDTOMongoImpl, ObjectId> implements EntryDAO<EntryDTOMongoImpl> {
    private static final Logger logger = Logger.getLogger(EntryDAOMongoImpl.class);

    @Inject
    public EntryDAOMongoImpl(@Assisted Class<EntryDTOMongoImpl> entityClass) throws UnknownHostException {
        super(entityClass);
    }
    ...
}

厂：

public interface EntryDAOFactory {
    public EntryDAOMongoImpl buildEntryDAO(Class<EntryDTOMongoImpl> entityClass);
}

模块：

public class EntryDAOModule extends AbstractModule {

    @Override
    protected void configure() {
        //bind(EntryDAO.class).to(EntryDAOMongoImpl.class); // what should this be?

        FactoryModuleBuilder factoryModuleBuilder = new FactoryModuleBuilder();
        install(factoryModuleBuilder.build(EntryDAOFactory.class));
    }
}

用法：

Injector injector = Guice.createInjector(new EntryDAOModule());
EntryDAOFactory factory = injector.getInstance(EntryDAOFactory.class);
this.entryDAO = factory.buildEntryDAO(entityClass);

如果您打算将EntryDAOMongoImpl用作singelton（自然使用单身imo），那么您可以在模块内无需辅助注射的情况下执行以下操作：

public class EntryDAOModule extends AbstractModule {

    @Override
    protected void configure() {
        EtnryDTOMongoImpl dto = new EntryDTOMongoImpl(TargetEntry.class); //guessing here
        bind(EntryDAO.class).toInstance(new EntryDAOMongoImpl(dto)); // singleton   
    }
}

如果有帮助，请告诉我

如何在构造函数接受Class的情况下注入Guice`Codule`？

1 个答案: