解析某個特定網站時Android應用程序崩潰

Question

我試圖構建我的第一個Android應用程序，用於我學校的新聞發佈。我使用Jsoup，但每次都會崩潰。這個問題只發生在這個網頁上。當我輸入不同的網址時，它就可以工作。這裏是鏈接的頁面：http://www.marianum24.de/~aushang/index.html 這裏是我的代碼：

private String loadXmlFromNetwork(String urlString) throws IOException { 

    Document doc = null; 
    StringBuilder htmlString = new StringBuilder(); 

    try { 
     doc = Jsoup.connect(urlString).get(); 
     htmlString.append(doc.body().text()); 
    } catch (IOException e) { 
     return getResources().getString(R.string.connection_error); 
    } 

    return htmlString.toString(); 
} 

最後我的日誌：

11-27 11:30:33.081: D/gralloc_goldfish(5227): Emulator without GPU emulation detected. 
11-27 11:30:35.251: D/dalvikvm(5227): GC_FOR_ALLOC freed 149K, 9% free 2768K/3024K, paused 51ms, total 51ms 
11-27 11:30:36.292: D/dalvikvm(5227): GC_FOR_ALLOC freed 398K, 15% free 2881K/3380K, paused 50ms, total 51ms 
11-27 11:30:37.411: D/dalvikvm(5227): GC_FOR_ALLOC freed 181K, 9% free 3215K/3496K, paused 59ms, total 59ms 
11-27 11:30:37.952: W/dalvikvm(5227): threadid=12: thread exiting with uncaught exception (group=0x414c4700) 
11-27 11:30:37.971: E/AndroidRuntime(5227): FATAL EXCEPTION: AsyncTask #1 
11-27 11:30:37.971: E/AndroidRuntime(5227): java.lang.RuntimeException: An error occured while executing doInBackground() 
11-27 11:30:37.971: E/AndroidRuntime(5227):  at android.os.AsyncTask$3.done(AsyncTask.java:299) 
11-27 11:30:37.971: E/AndroidRuntime(5227):  at java.util.concurrent.FutureTask.finishCompletion(FutureTask.java:352) 
11-27 11:30:37.971: E/AndroidRuntime(5227):  at java.util.concurrent.FutureTask.setException(FutureTask.java:219) 
11-27 11:30:37.971: E/AndroidRuntime(5227):  at java.util.concurrent.FutureTask.run(FutureTask.java:239) 
11-27 11:30:37.971: E/AndroidRuntime(5227):  at android.os.AsyncTask$SerialExecutor$1.run(AsyncTask.java:230) 
11-27 11:30:37.971: E/AndroidRuntime(5227):  at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1080) 
11-27 11:30:37.971: E/AndroidRuntime(5227):  at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:573) 
11-27 11:30:37.971: E/AndroidRuntime(5227):  at java.lang.Thread.run(Thread.java:841) 
11-27 11:30:37.971: E/AndroidRuntime(5227): Caused by: java.lang.NullPointerException 
11-27 11:30:37.971: E/AndroidRuntime(5227):  at com.boldog.aushang.MainActivity.loadXmlFromNetwork(MainActivity.java:199) 
11-27 11:30:37.971: E/AndroidRuntime(5227):  at com.boldog.aushang.MainActivity.access$0(MainActivity.java:192) 
11-27 11:30:37.971: E/AndroidRuntime(5227):  at com.boldog.aushang.MainActivity$DownloadXmlTask.doInBackground(MainActivity.java:175) 
11-27 11:30:37.971: E/AndroidRuntime(5227):  at com.boldog.aushang.MainActivity$DownloadXmlTask.doInBackground(MainActivity.java:1) 
11-27 11:30:37.971: E/AndroidRuntime(5227):  at android.os.AsyncTask$2.call(AsyncTask.java:287) 
11-27 11:30:37.971: E/AndroidRuntime(5227):  at java.util.concurrent.FutureTask.run(FutureTask.java:234) 
11-27 11:30:37.971: E/AndroidRuntime(5227):  ... 4 more 
11-27 11:30:42.774: I/Choreographer(5227): Skipped 78 frames! The application may be doing too much work on its main thread. 
11-27 11:31:28.801: I/Process(5227): Sending signal. PID: 5227 SIG: 9 

我希望你能告訴我問題所在。

Answer 1

檢查MainActivity 199行。那裏有null。

我敢打賭，在這條線：

htmlString.append(doc.body().text()); 

我想doc可能是null。

Answer 2

您的問題似乎是一個驗證問題。簡而言之，您將原始HTML文件傳遞給您的Document對象，就好像它是格式正確的XML一樣。事實並非如此。按照w3.org驗證服務，

http://validator.w3.org/check?uri=http%3A%2F%2Fwww.marianum24.de%2F~aushang%2Findex.html&charset=%28detect+automatically%29&doctype=Inline&group=0

此時至少有8個錯誤和警告1與網站。

如果我是你，我會運行一些檢查來解析我的輸入文件之前做任何處理。