Question

我正在尝试注入多个datastax Mapper，但Provider创建代码始终相同，为每种类型编写提供程序是多余的。

提供商代码是

public class FooMapperProvider extends Provider<Mapper<Foo>> () {
    private final MappingManager mappingManager

    @Inject
    FooMapperProvider(MappingManager) {
        this.mappingManager = mappingManager;
    }

    @Override
    public Mapper<Foo> get() {
        mappingManager.mapper(Foo.class);
    }
}

是否可以绑定或创建

的提供程序

bind(Foo.class).toProvider(GenericMapperProvider.class)
bind(Bar.class).toProvider(GenericMapperProvider.class)

以get方式调用mappingManager.mapper public class MapperProvider<T> implements Provider<Mapper<T>> { private final MappingManager mappingManager; private final Class klass; @Inject public MapperProvider(MappingManager mappingManager, Class klass) { this.mappingManager = mappingManager; this.klass = klass; } @Override public Mapper<T> get() { return mappingManager.mapper(klass); } }可以根据特定绑定的类创建映射器吗？

我想过尝试像

这样的东西

{{1}}

但我无法弄清楚如何指定类和注入依赖

Answer 1

public class MapperProvider<T> implements Provider<Mapper<T>> {
    private final MappingManager mappingManager;
    private final TypeLiteral<T> type;

    @Inject
    public MapperProvider(MappingManager mappingManager, TypeLiteral<T> type) {
        this.mappingManager = mappingManager;
        this.type = type;
    }

    @Override
    public Mapper<T> get() {
        return mappingManager.mapper(type.getRawType());
    }
}

bind(new TypeLiteral<Mapper<Foo>>(){})
       .toProvider(new TypeLiteral<MapperProvider<Foo>>(){});

单个提供程序，它基于类绑定创建不同类型的对象

1 个答案: