Flutter Web在进行http调用时收到“ XMLHttpRequest”错误

如何解决Flutter Web在进行http调用时收到“ XMLHttpRequest”错误

我正在尝试查询在本地服务器上运行的Apache演练，但出现以下错误。请帮助我，我也尝试在该项目的/ web文件夹中添加“ .htaccess”，但此操作无效....谢谢！

http
    .post(
  'http://localhost:8047/query.json',headers: <String,String>{
    'Content-Type': 'application/json','Access-Control-Allow-Headers':
        'Origin,Content-Type,Cookie,X-CSRF-TOKEN,Accept,Authorization,X-XSRF-TOKEN,Access-Control-Allow-Origin','Access-Control-Expose-Headers': "" 'Authorization,authenticated','Access-Control-Allow-Origin': '*','Access-Control-Allow-Methods': 'GET,POST,OPTIONS,DELETE,PUT','Access-Control-Allow-Credentials': 'true',},body: jsonEncode(<String,String>{
    'queryType': 'SQL','query':
        'select * from dfs.`C:/Users/drill/data/*.parquet`'
  }),)
    .then((_response) {
  setState(() {
     response = jsonDecode(_response.body);
  });
}

---

Error: XMLHttpRequest error.
    C:/b/s/w/ir/cache/builder/src/out/host_debug/dart-sdk/lib/_internal/js_dev_runtime/private/ddc_runtime/errors.dart 264:20      get current
packages/http/src/browser_client.dart 84:22                                                                                    <fn>
C:/b/s/w/ir/cache/builder/src/out/host_debug/dart-sdk/lib/async/zone.dart 1450:54                                              runUnary
C:/b/s/w/ir/cache/builder/src/out/host_debug/dart-sdk/lib/async/future_impl.dart 143:18                                        handleValue
C:/b/s/w/ir/cache/builder/src/out/host_debug/dart-sdk/lib/async/future_impl.dart 696:44                                        handleValueCallback
C:/b/s/w/ir/cache/builder/src/out/host_debug/dart-sdk/lib/async/future_impl.dart 725:32                                        _propagateToListeners
C:/b/s/w/ir/cache/builder/src/out/host_debug/dart-sdk/lib/async/future_impl.dart 519:7                                         [_complete]
C:/b/s/w/ir/cache/builder/src/out/host_debug/dart-sdk/lib/async/stream_pipe.dart 61:11                                         _cancelAndValue
C:/b/s/w/ir/cache/builder/src/out/host_debug/dart-sdk/lib/async/stream.dart 1300:7                                             <fn>
C:/b/s/w/ir/cache/builder/src/out/host_debug/dart-sdk/lib/_internal/js_dev_runtime/private/ddc_runtime/operations.dart 324:14  _checkAndCall
C:/b/s/w/ir/cache/builder/src/out/host_debug/dart-sdk/lib/_internal/js_dev_runtime/private/ddc_runtime/operations.dart 329:39  dcall
C:/b/s/w/ir/cache/builder/src/out/host_debug/dart-sdk/lib/html/dart2js/html_dart2js.dart 37287:58                              <fn>
    at Object.createErrorWithStack (http://localhost:62659/dart_sdk.js:4348:12)
    at Object._rethrow (http://localhost:62659/dart_sdk.js:37892:16)
    at async._AsyncCallbackEntry.new.callback (http://localhost:62659/dart_sdk.js:37886:13)
    at Object._microtaskLoop (http://localhost:62659/dart_sdk.js:37718:13)
    at _startMicrotaskLoop (http://localhost:62659/dart_sdk.js:37724:13)

解决方法

我当前有相同的错误消息，并且非常容易引起误解。似乎只是表明该请求由于任何原因而失败。

要对其进行调试，请使用Chrome的DevTools（Ctrl + Shift + C），转到“网络”并在此处进行检查。您几乎可以肯定地看到，请求的某些部分不是您想要的，并且请求失败。

编辑：也许这是一个CORS问题，那么这个很好的答案可能会有所帮助：No 'Access-Control-Allow-Origin' header is present on the requested resource—when trying to get data from a REST API

,

您正在运行的设备似乎有问题。 看起来很简单，但是在任务管理器中，请确保退出所有chrome进程，然后执行flutter clean然后flutter run -d chrome 这为我解决了这个问题。