Java：泛型：从泛型方法获取对象类型 T 并访问其方法

debugcn 发表于 Dev

阳光明媚

    public interface MyMapperInterface<Y, Z> {

    Y map(Z zObject);

    }

    public class One{
    }

    public class Two{
    }


    public MapperOneTwo  implements MyMapperInterface<One, Two> {

        public One map(Two twoObject){
            //Based on properties of Two, a new One Object is created and returned.
        }

    }


public MapperThreeFour  implements MyMapperInterface<Three, Four> {

        public One map(Two twoObject){
            //Now for two other class, Three and Four, there is a new 
              mapper.
              Based on properties of Two, a new One Object is created and 
               returned.
        }

    }





    FactoryClass

    public class Factory {

        public <T> T getClassInstance(String params){
          if (params.equals("a")) { 
    return (T) new MapperOneTwo();
    } else if (params.equals("b")){
    return (T) new MapperThreeFour();
    }
    }

    }

用法我有一个处理程序类，它需要映射并传递其他类型。所以我希望将类型传递给工厂，然后工厂提供相应的映射器，然后该映射器完成其工作并返回相应类型的对象。但问题是现在返回的对象是 Object 类型，并且这个处理程序类必须在进一步传递它之前对其进行类型转换。

有没有办法避免类型转换并且仍然能够创建这样的工厂？

谢谢

阳光明媚

以下工厂将解决上述问题，而无需进行类型转换：

public class Factory {


    public <Y, Z> Mapper<Y, Z> create(Class<Y> yClassType) {

        Mapper mapper;
        if (yClassType.equals(One.class)) {
            mapper = new MapperOneTwo();
        } else {
            //Handle default behaviour
        }
        return mapper;
    }

}

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