dart - 如何在Dart中异步读取文件？

Question

上面的问题是在Dart Google+社区提出的，没有给出明确的答案，所以我想在这里重复这个问题，因为我真的很想知道。这是Dart社区的帖子:

https://plus.google.com/u/0/103493864228790779294/posts/U7VTyX5h7HR

那么有无错误处理的正确方法是什么呢？

Answer 1

您链接到的问题是关于异步读取多个文件的内容，这是一个较难的问题。我认为Florian的解决方案没有问题。简化一下，这似乎可以成功地异步读取文件:

import 'dart:async';
import 'dart:io';

void main() {
  new File('/home/darshan/so/asyncRead.dart')
    .readAsString()
    ..catchError((e) => print(e))
    .then(print);

  print("Reading asynchronously...");
}

输出:

Reading asynchronously...import 'dart:async';import 'dart:io';void main() {  new File('/home/darshan/so/asyncRead.dart')    .readAsString()    ..catchError((e) => print(e))    .then(print);  print("Reading asynchronously...");}

For the record, here's Florian Loitsch's (slightly modified) solution to the initial problem:

import 'dart:async';
import 'dart:io';

void main() {
  new Directory('/home/darshan/so/j')
    .list()
    .map((f) => f.readAsString()..catchError((e) => print(e)))
    .toList()
    .then(Future.wait)
    .then(print);

  print("Reading asynchronously...");
}