Android Studio 中的 FileNotFoundException，但在浏览器中运行良好

Question

我正在尝试连接到网站以接收一些 JSON 信息。当我使用连接的 Nexus 7 设备在 Android Studio 中运行应用程序时，我得到一个 java.io.FileNotFound 异常，但如果我单击未找到的文件的名称，预期的响应会立即显示在我的浏览器中。这对我来说是一个新应用程序，但我过去做过类似的事情。在过去的 2 天里，我一直在尝试多种方法，但似乎找不到问题所在。当我调用 connection.getInputStream() 时，代码会爆炸。所有这些都在 AsyncTask 中运行。

我的代码

public byte[] getUrlBytes(String urlSpec) throws IOException{
    URL url = new URL(urlSpec);
    // urlSpec: https://api.weather.gov/points/48.0174,-115.2278

    try {
        connection = (HttpsURLConnection) url.openConnection();
    } catch (IOException ioe) {
        Log.d(TAG, "connection ioe: " + ioe.toString());
        Toast.makeText(context, "@string/can_not_connect",
                Toast.LENGTH_LONG).show();
    }


    try {
        ByteArrayOutputStream out = new ByteArrayOutputStream();
        InputStream in = connection.getInputStream(); *** Blows up here ****

        if (connection.getResponseCode() != HttpURLConnection.HTTP_OK) {
            Log.d(TAG, "connection Response code: " + 
                  connection.getResponseMessage());
        }

        int bytesRead = 0;
        byte[] buffer = new byte[1024];
        while ((bytesRead = in.read(buffer)) > 0) {
            out.write(buffer, 0, bytesRead);
        }

        out.close();
        return out.toByteArray();
    } finally {
        connection.disconnect();
    }
}

Logcat

04-02 15:40:59.693 32471-32495/com.drme.weathertest E/WeatherFetcher: Failed 
 to fetch items
java.io.FileNotFoundException: https://api.weather.gov/points/48.0174,-115.2278 
*** Note that if I click on this file name, it works in my browser ***
    at com.android.okhttp.internal.http.HttpURLConnectionImpl.getInputStream(HttpURLConnectionImpl.java:206)       
    at com.android.okhttp.internal.http.DelegatingHttpsURLConnection.getInputStream(DelegatingHttpsURLConnection.java:210)   
    at com.android.okhttp.internal.http.HttpsURLConnectionImpl.getInputStream(HttpsURLConnectionImpl.java:25)
    at com.drme.weatherNoaa.WeatherFetcher.getUrlBytes(WeatherFetcher.java:148)
    at com.drme.weatherNoaa.WeatherFetcher.getUrlString(WeatherFetcher.java:183)
    at com.drme.weatherNoaa.WeatherFetcher.downloadGridPoints(WeatherFetcher.java:202)
    at com.drme.weatherNoaa.WeatherFetcher.requestForecast(WeatherFetcher.java:262)
    at com.drme.weatherNoaa.WeatherFragment$SearchTask.doInBackground(WeatherFragment.java:329)
    at com.drme.weatherNoaa.WeatherFragment$SearchTask.doInBackground(WeatherFragment.java:296)
    at android.os.AsyncTask$2.call(AsyncTask.java:292)
    at java.util.concurrent.FutureTask.run(FutureTask.java:237)
    at android.os.AsyncTask$SerialExecutor$1.run(AsyncTask.java:231)
    at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1112)
    at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:587)
    at java.lang.Thread.run(Thread.java:818)

感谢您的帮助。

Answer 1

在额外阅读 web 服务文档（其中一些对我来说似乎有点薄）和网络上的一些额外帖子之后，答案是它们需要在请求中包含 Acceptance 和 User-agent 标头。我已经进行了这些更改，现在代码可以正常工作了。

新的静态常量

private static final String ACCEPT_PROPERTY = "application/geo+json;version=1";
private static final String USER_AGENT_PROPERTY = "xxxx.com (xxxxxxxxx@gmail.com)";

代码更改

 connection = (HttpsURLConnection) url.openConnection();
 connection.setRequestProperty("Accept", ACCEPT_PROPERTY);  // added
 connection.setRequestProperty("User-Agent", USER_AGENT_PROPERTY); // added

不需要进行其他更改，尽管我花了一段时间才弄清楚如何添加标题以及它们的格式可能是什么。

感谢您查看此内容。