java可选接口(interface)方法: Ambiguous method reference

Question

我已经编码了:

this.referenceService.get(id)
    .map(Reference::hashCode)
    .map(Integer::toString);

我收到此编译错误:

Ambiguous method reference: both toString() and toString(int) from the type Integer are eligible

我该如何解决这个问题？

Answer 1

您有两种可能的解决方案:

用 lambda 替换它:

this.referenceService.get(id)
    .map(ref-> Integer.toString(ref.hashCode()));

使用Objects.toString()

this.referenceService.get(id)
    .map(Reference::hashCode)
    .map(Objects::toString); // this will cal toString method on you hash

编写自己的方法:

this.referenceService.get(id)
    .map(this::toHashString);

private Strign toHashString(Reference ref) {
  return Integer.toString(ref.hashCode());
}