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我正在嘗試使用Android的MediaPlayer庫流式傳輸音頻。如何確定某個特定端口是否對防火牆後面的傳入流量打開
在某些情況下，流URL是一個不尋常的端口。例如，http://203.150.225.77:8400。如果我嘗試從瀏覽器的防火牆後面訪問此流，它會給我一個「糟糕！Google Chrome無法連接到203.150.225.77:8400」的錯誤。
Frrom媒體播放器在我的Android設備，我得到：MusicStream(1806): Media Player Error: Stream URL Invalid (1) -1004
目前，我只是處理這個異常。不過，我希望能夠在啓動MediaPlayer之前預先測試URL以確定流是否可用。
所以，我創建了一個功能來測試使用HttpURLConnection類，如下所示的網址：
protected int isURLValid(MusicStream streamInstance, String urlString)
{
streamInstance.timeout = 0;
int success = 0;
try
{
URL url;
url = new URL(urlString);
HttpURLConnection urlConnection;
urlConnection = (HttpURLConnection) url.openConnection();
urlConnection.setConnectTimeout(1000);
urlConnection.setReadTimeout(1000);
urlConnection.getHeaderFields();
new Thread(new InterruptThread(Thread.currentThread(), urlConnection,streamInstance)).start();
if (streamInstance.timeout == 0)
{
success = 1;
}
}
catch (MalformedURLException e) {
// TODO Auto-generated catch block
e.printStackTrace();
Log.w("MusicStream", "MalformedURLException");
Log.w("MusicStream", e);
} catch (IOException e) {
// TODO Auto-generated catch block
e.printStackTrace();
Log.w("MusicStream", "IOException");
Log.w("MusicStream", e);
} catch (Exception e) {
this.exception = e;
Log.w("MusicStream", "Exception");
Log.w("MusicStream", e);
}
return success;
}
正如你可以在上面的代碼中看到，我開始一個新的線程5000毫秒後超時。下面是我的線程：只要將我的設備從無線到
if (isURLValid(streamInstance[0],streamURL) == 1){
// Valid URL!
Log.d("MusicStream", "The stream is valid!");
this.ResultString = streamURL;
streamInstance[0].setFirewallError(MusicStream.GONE,streamURL);
}
else{
// Streaming URL invalid.
// Firewall Error
errorCode = MusicStream.FIREWALL_ERROR;
Log.d("MusicStream", "The stream is not valid!");
streamInstance[0].setFirewallError(MusicStream.VISIBLE,streamURL);
}
日誌輸出如下
A stream has been supplied: http://203.150.225.77:8400
The stream is valid!
MusicStream(1806): Media Player Error: Stream URL Invalid (1) -1004
：
public class InterruptThread implements Runnable {
Thread parent;
URLConnection con;
MusicStream streamInstance;
public InterruptThread(Thread parent, URLConnection con, MusicStream streamInstance) {
this.parent = parent;
this.con = con;
this.streamInstance = streamInstance;
}
public void run() {
try {
Thread.sleep(5000);
} catch (InterruptedException e) {
}
Log.d("MusicStream", "Timer thread forcing parent to quit connection");
((HttpURLConnection)con).disconnect();
Log.d("MusicStream","Timer thread closed connection held by parent, exiting");
streamInstance.timeout = 1;
}
}
Nontheless，當我引用我的功能3G，流媒體的作品，所以我有點不知所措，爲什麼我的網址檢查機制在防火牆後回來時有效。任何人都可以看到任何理由，爲什麼我的支票回來有效，並可能提出一個建議，我怎樣才能以更簡單的方式檢查狀態？
額外的想法：我在想，也許一些防火牆會迴應一個「封鎖」的頁面，在這種情況下，獲取標題將無法正常工作。但是，這不是這種情況。