Java 将一个值转换为两个类

我想知道如何将对象强制转换为

。我的意思是，我有一个方法，应该是排序值。如果这些值是数字，我想把它们相互比较

我天真的第一次尝试是

  Object value1 = getAttributeValueFromHit(hit1, attributeName);
  Object value2 = getAttributeValueFromHit(hit2, attributeName);
  :
  :
  } else if (value1 instanceof Number) {
    Number nValue1 = (Number & Comparable<Number>) value1;
    /*
    Multiple markers at this line
      - Type safety: Unchecked cast from Object to Number & Comparable<Number>
      - Additional bounds are not allowed in cast operator at source levels below 1.8
    */
    Number nValue2 = (Number & Comparable<Number>) value2;
    /* same as above */
    return compareNumbers(nValue1, nValue2);
    /*
    Multiple markers at this line
      - Type safety: Unchecked cast from Object to Number & Comparable<Number>
      - Type safety: Unchecked cast from Object to Number & Comparable<Number>
      - Bound mismatch: The generic method compareNumbers(T, T) of type DataHitComparator is not applicable for the arguments (Number, Number). The inferred type Number is not a valid substitute for the bounded parameter <T extends Number & Comparable<T>>
      - Bound mismatch: The generic method compareNumbers(T, T) of type DataHitComparator is not applicable for the arguments (Number & Comparable<Number>, Number & Comparable<Number>). The inferred type Number & Comparable<Number> is not a valid substitute for the bounded parameter <T extends Number & Comparable<T>>
    */
  }

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我是否有机会在Java 7中实现这一点？

使用泛型类型参数（您可以在方法中定义一个参数，也可以重用在类范围中定义的参数）

以及它的号召：

    return compareNumbers((Number) value1, (Number) value2);

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@SilviuBurcea试过什么？我尝试了一件事并发布了结果。哇，很好：）我希望您不介意我在您的答案中添加了一个版本的

compareNumbers（）

。没问题，有意义：-）

public static <X extends Number & Comparable<X>> int test() {
    Object o1 = getAttributeValueFromHit(hit1, attributeName);
    Object o2 = getAttributeValueFromHit(hit2, attributeName);
    return compareNumbers((X) o1, (X) o2);
}

private <T extends Number & Comparable<T>> int compareNumbers(Number number1, Number number2) {
  @SuppressWarnings("unchecked")
  T number1Cast = (T) number1;
  @SuppressWarnings("unchecked")
  T number2Cast = (T) number2;
  return number1Cast.compareTo(number2Cast);
}

    return compareNumbers((Number) value1, (Number) value2);