Scala到Java8流兼容性问题

Question

(阶)

Files.walk(Paths.get("")).forEach(x => log.info(x.toString))

给

Error:(21, 16) missing parameter type
  .forEach(x => log.info(x.toString))
           ^

和(java8)

Files.walk(Paths.get("")).forEach(x -> System.out.println(x.toString()));

工作良好

怎么了？

Answer 1

stream.forEach(x -> foo()) 在java中是语法糖

stream.forEach(
  new Consumer<Path> { public void accept(Path x) { foo(); } }
)

这与x => ...scala 完全不同,scala是一个实例Function[Path,Unit].

试试这个;

Files.walk(Paths.get(""))
  .forEach(new Consumer[Path] { def accept(s: Path) = println(s) })