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Android - .getInputStream（）不斷崩潰

2013-07-01 103 views
2

我對Android，Java和HTML真的很陌生。所以我幾乎塞滿了。 我只是想從一個Android應用程序的URL獲取數據。 我在java中嘗試了下面的代碼，它工作正常，所以我真的堅持它有什麼問題。 我試着用搜索引擎，並使用不同的選項，如設置連接時間Android - .getInputStream（）不斷崩潰

URL url = new URL("http://www.google.com/"); 
    HttpURLConnection conn = (HttpURLConnection) url.openConnection(); 
    conn.setDoInput(true); 
    conn.setDoOutput(true); 
    try { 
     input = new InputStreamReader(conn.getInputStream()); 
     in =new BufferedReader(input); 
    }

我嘗試了很多不同的版本，如添加了一堆東西一樣的： urlConnection.setRequestProperty（「連接」，「備存─活」）; urlConnection.setRequestProperty（「ConnectionTimeout」，「12000」）; urlConnection.setRequestProperty（「Content-Length」，「」+ request.length）;

我認爲以下崗位有類似的問題： IOException with URLConnection and getInputStream

我沒有得到一個IOException（嗯，至少我不這麼認爲），但我得到這個（和一大堆其他的）

07-01 23：18：33.870：E/AndroidRuntime（30713）：java.lang.IllegalStateException：無法執行活動

的方法是的，我沒有添加權限到INTERNET和ACCESS_NETWORK_STATE

<uses-permission android:name="android.permission.INTERNET" /> 
    <uses-permission android:name = "android.permission.ACCESS_NETWORK_STATE"/>

我使用Eclipse並在我的Android HTC One X上運行。 請幫忙。提前致謝！

這裏的堆棧跟蹤後，我加入的AsyncTask：

07-02 00:02:34.775: W/IInputConnectionWrapper(3799): getExtractedText on inactive InputConnection 
07-02 00:02:34.785: W/IInputConnectionWrapper(3799): getTextBeforeCursor on inactive InputConnection 
07-02 00:02:34.785: W/IInputConnectionWrapper(3799): getSelectedText on inactive InputConnection 
07-02 00:02:34.785: W/IInputConnectionWrapper(3799): getTextAfterCursor on inactive InputConnection 
07-02 00:02:34.790: W/IInputConnectionWrapper(3799): getExtractedText on inactive InputConnection 
07-02 00:02:34.795: W/IInputConnectionWrapper(3799): getTextBeforeCursor on inactive InputConnection 
07-02 00:02:34.795: W/IInputConnectionWrapper(3799): getExtractedText on inactive InputConnection 
07-02 00:02:34.795: W/IInputConnectionWrapper(3799): getTextBeforeCursor on inactive InputConnection 
07-02 00:02:34.800: W/IInputConnectionWrapper(3799): getSelectedText on inactive InputConnection 
07-02 00:02:34.800: W/IInputConnectionWrapper(3799): getTextAfterCursor on inactive InputConnection 
07-02 00:02:34.800: W/IInputConnectionWrapper(3799): getExtractedText on inactive InputConnection 
07-02 00:02:34.805: W/IInputConnectionWrapper(3799): getTextBeforeCursor on inactive InputConnection 
07-02 00:02:34.805: W/IInputConnectionWrapper(3799): getSelectedText on inactive InputConnection 
07-02 00:02:34.810: W/IInputConnectionWrapper(3799): getTextAfterCursor on inactive InputConnection 
07-02 00:02:34.810: W/IInputConnectionWrapper(3799): beginBatchEdit on inactive InputConnection 
07-02 00:02:34.815: W/IInputConnectionWrapper(3799): getExtractedText on inactive InputConnection 
07-02 00:02:34.815: W/IInputConnectionWrapper(3799): getTextBeforeCursor on inactive InputConnection 
07-02 00:02:34.820: W/IInputConnectionWrapper(3799): getSelectedText on inactive InputConnection 
07-02 00:02:34.820: W/IInputConnectionWrapper(3799): getTextAfterCursor on inactive InputConnection 
07-02 00:02:34.830: W/IInputConnectionWrapper(3799): getExtractedText on inactive InputConnection 
07-02 00:02:34.830: W/IInputConnectionWrapper(3799): getTextBeforeCursor on inactive InputConnection 
07-02 00:02:34.830: W/IInputConnectionWrapper(3799): getSelectedText on inactive InputConnection 
07-02 00:02:34.835: W/IInputConnectionWrapper(3799): getTextAfterCursor on inactive InputConnection 
07-02 00:02:34.845: W/IInputConnectionWrapper(3799): endBatchEdit on inactive InputConnection 
07-02 00:02:34.845: W/IInputConnectionWrapper(3799): getExtractedText on inactive InputConnection 
07-02 00:02:34.845: W/IInputConnectionWrapper(3799): getTextBeforeCursor on inactive InputConnection 
07-02 00:02:34.850: W/IInputConnectionWrapper(3799): getSelectedText on inactive InputConnection 
07-02 00:02:34.850: W/IInputConnectionWrapper(3799): getTextAfterCursor on inactive InputConnection 
07-02 00:02:34.855: W/IInputConnectionWrapper(3799): beginBatchEdit on inactive InputConnection 
07-02 00:02:34.855: W/IInputConnectionWrapper(3799): setComposingRegion on inactive InputConnection 
07-02 00:02:34.855: W/IInputConnectionWrapper(3799): endBatchEdit on inactive InputConnection 
07-02 00:02:34.865: W/IInputConnectionWrapper(3799): getExtractedText on inactive InputConnection 
07-02 00:02:34.865: W/IInputConnectionWrapper(3799): getTextBeforeCursor on inactive InputConnection 
07-02 00:02:34.870: W/IInputConnectionWrapper(3799): getSelectedText on inactive InputConnection 
07-02 00:02:34.870: W/IInputConnectionWrapper(3799): getTextAfterCursor on inactive InputConnection 
07-02 00:05:06.105: W/LoadedApk(5867): pakageInfo is null! try again 
07-02 00:05:06.105: W/LoadedApk(5867): packageInfo still null! 
07-02 00:05:06.110: D/LoadedApk(5867): dalvik.system.VMStack.getThreadStackTrace(Native Method) 
07-02 00:05:06.110: D/LoadedApk(5867): java.lang.Thread.getStackTrace(Thread.java:599) 
07-02 00:05:06.110: D/LoadedApk(5867): android.app.LoadedApk.initializeJavaContextClassLoader(LoadedApk.java:388) 
07-02 00:05:06.110: D/LoadedApk(5867): android.app.LoadedApk.getClassLoader(LoadedApk.java:330) 
07-02 00:05:06.110: D/LoadedApk(5867): android.app.LoadedApk.makeApplication(LoadedApk.java:535) 
07-02 00:05:06.110: D/LoadedApk(5867): android.app.ActivityThread.handleBindApplication(ActivityThread.java:4803) 
07-02 00:05:06.110: D/LoadedApk(5867): android.app.ActivityThread.access$1300(ActivityThread.java:151) 
07-02 00:05:06.110: D/LoadedApk(5867): android.app.ActivityThread$H.handleMessage(ActivityThread.java:1401) 
07-02 00:05:06.110: D/LoadedApk(5867): android.os.Handler.dispatchMessage(Handler.java:99) 
07-02 00:05:06.110: D/LoadedApk(5867): android.os.Looper.loop(Looper.java:155) 
07-02 00:05:06.110: D/LoadedApk(5867): android.app.ActivityThread.main(ActivityThread.java:5493) 
07-02 00:05:06.110: D/LoadedApk(5867): java.lang.reflect.Method.invokeNative(Native Method) 
07-02 00:05:06.110: D/LoadedApk(5867): java.lang.reflect.Method.invoke(Method.java:511) 
07-02 00:05:06.110: D/LoadedApk(5867): com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:1028) 
07-02 00:05:06.110: D/LoadedApk(5867): com.android.internal.os.ZygoteInit.main(ZygoteInit.java:795) 
07-02 00:05:06.110: D/LoadedApk(5867): dalvik.system.NativeStart.main(Native Method) 
07-02 00:05:09.565: I/dalvikvm-heap(6053): Grow heap (frag case) to 5.448MB for 1705652-byte allocation 
07-02 00:05:09.810: I/dalvikvm-heap(6053): Grow heap (frag case) to 8.340MB for 3034580-byte allocation 
07-02 00:05:09.905: I/MediaPlayer(6053): setLPAflag() in 
07-02 00:05:09.905: I/MediaPlayer(6053): mContext is null, can't getMirrorDisplayStatus!!! 
07-02 00:05:09.905: I/MediaPlayer(6053): setLPAflag() out 
07-02 00:05:09.910: W/MediaPlayer(6053): info/warning (1, 902) 
07-02 00:05:09.915: D/MediaPlayer(6053): [DLNA]contentType = 902 
07-02 00:05:09.915: D/MediaPlayer(6053): doStart() in 
07-02 00:05:09.915: D/MediaPlayer(6053): getIntParameter = 902 
07-02 00:05:10.190: D/MediaPlayer(6053): Mediaplayer receives message, message type: 200 
07-02 00:05:10.190: I/MediaPlayer(6053): Info (1,902) 
07-02 00:05:10.190: D/MediaPlayer(6053): Mediaplayer receives message, message type: 5 
07-02 00:05:10.190: D/MediaPlayer(6053): Mediaplayer receives message, message type: 1 
07-02 00:05:10.295: E/(6053): file /data/data/com.nvidia.NvCPLSvc/files/driverlist.txt: not found! 
07-02 00:05:10.295: I/(6053): Attempting to load EGL implementation /system/lib//egl/libEGL_tegra_impl 
07-02 00:05:10.485: I/(6053): Loaded EGL implementation /system/lib//egl/libEGL_tegra_impl 
07-02 00:05:10.595: I/(6053): Loading GLESv2 implementation /system/lib//egl/libGLESv2_tegra_impl 
07-02 00:05:11.080: W/IInputConnectionWrapper(6053): getExtractedText on inactive InputConnection 
07-02 00:05:11.140: W/IInputConnectionWrapper(6053): getTextBeforeCursor on inactive InputConnection 
07-02 00:05:11.430: I/dalvikvm-heap(6053): Grow heap (frag case) to 10.851MB for 2731536-byte allocation 
07-02 00:05:11.830: I/MediaPlayer(6053): setLPAflag() in 
07-02 00:05:11.830: I/MediaPlayer(6053): mContext is null, can't getMirrorDisplayStatus!!! 
07-02 00:05:11.830: I/MediaPlayer(6053): setLPAflag() out 
07-02 00:05:11.845: W/MediaPlayer(6053): info/warning (1, 902) 
07-02 00:05:11.870: W/IInputConnectionWrapper(6053): getSelectedText on inactive InputConnection 
07-02 00:05:11.875: D/MediaPlayer(6053): Mediaplayer receives message, message type: 200 
07-02 00:05:11.875: I/MediaPlayer(6053): Info (1,902) 
07-02 00:05:11.875: D/MediaPlayer(6053): Mediaplayer receives message, message type: 5 
07-02 00:05:11.875: D/MediaPlayer(6053): Mediaplayer receives message, message type: 1 
07-02 00:05:12.025: W/IInputConnectionWrapper(6053): getTextAfterCursor on inactive InputConnection 
07-02 00:05:12.600: D/MediaPlayer(6053): [DLNA]contentType = 902 
07-02 00:05:12.600: D/MediaPlayer(6053): doStart() in 
07-02 00:05:12.600: D/MediaPlayer(6053): getIntParameter = 902 
07-02 00:05:12.645: W/IInputConnectionWrapper(6053): getExtractedText on inactive InputConnection 
07-02 00:05:12.940: W/IInputConnectionWrapper(6053): getExtractedText on inactive InputConnection 
07-02 00:05:12.945: W/IInputConnectionWrapper(6053): getTextBeforeCursor on inactive InputConnection 
07-02 00:05:12.950: W/IInputConnectionWrapper(6053): getSelectedText on inactive InputConnection 
07-02 00:05:12.955: W/IInputConnectionWrapper(6053): getTextAfterCursor on inactive InputConnection 
07-02 00:05:12.960: W/IInputConnectionWrapper(6053): getExtractedText on inactive InputConnection 
07-02 00:05:12.965: W/IInputConnectionWrapper(6053): getTextBeforeCursor on inactive InputConnection 
07-02 00:05:12.980: W/IInputConnectionWrapper(6053): getExtractedText on inactive InputConnection 
07-02 00:05:12.980: W/IInputConnectionWrapper(6053): getTextBeforeCursor on inactive InputConnection 
07-02 00:05:12.985: W/IInputConnectionWrapper(6053): getSelectedText on inactive InputConnection 
07-02 00:05:12.985: W/IInputConnectionWrapper(6053): getTextAfterCursor on inactive InputConnection 
07-02 00:05:12.995: W/IInputConnectionWrapper(6053): getExtractedText on inactive InputConnection 
07-02 00:05:13.000: W/IInputConnectionWrapper(6053): getTextBeforeCursor on inactive InputConnection 
07-02 00:05:13.000: W/IInputConnectionWrapper(6053): getSelectedText on inactive InputConnection 
07-02 00:05:13.005: W/IInputConnectionWrapper(6053): getTextAfterCursor on inactive InputConnection 
07-02 00:05:13.005: W/IInputConnectionWrapper(6053): getExtractedText on inactive InputConnection 
07-02 00:05:13.010: W/IInputConnectionWrapper(6053): getTextBeforeCursor on inactive InputConnection 
07-02 00:05:13.010: W/IInputConnectionWrapper(6053): getSelectedText on inactive InputConnection 
07-02 00:05:13.010: W/IInputConnectionWrapper(6053): getTextAfterCursor on inactive InputConnection 
07-02 00:05:13.015: W/IInputConnectionWrapper(6053): getExtractedText on inactive InputConnection 
07-02 00:05:13.015: W/IInputConnectionWrapper(6053): getTextBeforeCursor on inactive InputConnection 
07-02 00:05:13.015: W/IInputConnectionWrapper(6053): getSelectedText on inactive InputConnection 
07-02 00:05:13.015: W/IInputConnectionWrapper(6053): getTextAfterCursor on inactive InputConnection 
07-02 00:05:13.015: W/IInputConnectionWrapper(6053): beginBatchEdit on inactive InputConnection 
07-02 00:05:13.020: W/IInputConnectionWrapper(6053): endBatchEdit on inactive InputConnection 
07-02 00:05:13.020: W/IInputConnectionWrapper(6053): getExtractedText on inactive InputConnection 
07-02 00:05:13.020: W/IInputConnectionWrapper(6053): getTextBeforeCursor on inactive InputConnection 
07-02 00:05:13.020: W/IInputConnectionWrapper(6053): getSelectedText on inactive InputConnection 
07-02 00:05:13.020: W/IInputConnectionWrapper(6053): getTextAfterCursor on inactive InputConnection 
07-02 00:05:13.025: W/IInputConnectionWrapper(6053): beginBatchEdit on inactive InputConnection 
07-02 00:05:13.025: W/IInputConnectionWrapper(6053): setComposingRegion on inactive InputConnection 
07-02 00:05:13.025: W/IInputConnectionWrapper(6053): endBatchEdit on inactive InputConnection 
07-02 00:05:13.025: W/IInputConnectionWrapper(6053): getExtractedText on inactive InputConnection 
07-02 00:05:13.025: W/IInputConnectionWrapper(6053): getTextBeforeCursor on inactive InputConnection 
07-02 00:05:13.025: W/IInputConnectionWrapper(6053): getSelectedText on inactive InputConnection 
07-02 00:05:13.025: W/IInputConnectionWrapper(6053): getTextAfterCursor on inactive InputConnection 
07-02 00:05:13.165: E/SpannableStringBuilder(6053): SPAN_EXCLUSIVE_EXCLUSIVE spans cannot have a zero length 
07-02 00:05:13.165: E/SpannableStringBuilder(6053): SPAN_EXCLUSIVE_EXCLUSIVE spans cannot have a zero length 
07-02 00:05:13.295: D/MediaPlayer(6053): Mediaplayer receives message, message type: 2 
07-02 00:05:16.440: W/System.err(6053): java.io.FileNotFoundException: http://www.google.com/ 
07-02 00:05:16.445: W/System.err(6053):  at libcore.net.http.HttpURLConnectionImpl.getInputStream(HttpURLConnectionImpl.java:177) 
07-02 00:05:16.445: W/System.err(6053):  at aiti.mit.edu.sa.wu.calculator.MyAsynTask.doInBackground(ActivityHi.java:139) 
07-02 00:05:16.445: W/System.err(6053):  at aiti.mit.edu.sa.wu.calculator.MyAsynTask.doInBackground(ActivityHi.java:1) 
07-02 00:05:16.445: W/System.err(6053):  at android.os.AsyncTask$2.call(AsyncTask.java:287) 
07-02 00:05:16.445: W/System.err(6053):  at java.util.concurrent.FutureTask$Sync.innerRun(FutureTask.java:305) 
07-02 00:05:16.445: W/System.err(6053):  at java.util.concurrent.FutureTask.run(FutureTask.java:137) 
07-02 00:05:16.445: W/System.err(6053):  at android.os.AsyncTask$SerialExecutor$1.run(AsyncTask.java:230) 
07-02 00:05:16.445: W/System.err(6053):  at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1076) 
07-02 00:05:16.450: W/System.err(6053):  at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:569) 
07-02 00:05:16.450: W/System.err(6053):  at java.lang.Thread.run(Thread.java:864) 
07-02 00:05:16.450: W/dalvikvm(6053): threadid=12: thread exiting with uncaught exception (group=0x40c392d0) 
07-02 00:05:16.460: E/AndroidRuntime(6053): FATAL EXCEPTION: AsyncTask #1 
07-02 00:05:16.460: E/AndroidRuntime(6053): java.lang.RuntimeException: An error occured while executing doInBackground() 
07-02 00:05:16.460: E/AndroidRuntime(6053):  at android.os.AsyncTask$3.done(AsyncTask.java:299) 
07-02 00:05:16.460: E/AndroidRuntime(6053):  at java.util.concurrent.FutureTask$Sync.innerSetException(FutureTask.java:273) 
07-02 00:05:16.460: E/AndroidRuntime(6053):  at java.util.concurrent.FutureTask.setException(FutureTask.java:124) 
07-02 00:05:16.460: E/AndroidRuntime(6053):  at java.util.concurrent.FutureTask$Sync.innerRun(FutureTask.java:307) 
07-02 00:05:16.460: E/AndroidRuntime(6053):  at java.util.concurrent.FutureTask.run(FutureTask.java:137) 
07-02 00:05:16.460: E/AndroidRuntime(6053):  at android.os.AsyncTask$SerialExecutor$1.run(AsyncTask.java:230) 
07-02 00:05:16.460: E/AndroidRuntime(6053):  at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1076) 
07-02 00:05:16.460: E/AndroidRuntime(6053):  at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:569) 
07-02 00:05:16.460: E/AndroidRuntime(6053):  at java.lang.Thread.run(Thread.java:864) 
07-02 00:05:16.460: E/AndroidRuntime(6053): Caused by: java.lang.NullPointerException 
07-02 00:05:16.460: E/AndroidRuntime(6053):  at aiti.mit.edu.sa.wu.calculator.MyAsynTask.doInBackground(ActivityHi.java:153) 
07-02 00:05:16.460: E/AndroidRuntime(6053):  at aiti.mit.edu.sa.wu.calculator.MyAsynTask.doInBackground(ActivityHi.java:1) 
07-02 00:05:16.460: E/AndroidRuntime(6053):  at android.os.AsyncTask$2.call(AsyncTask.java:287) 
07-02 00:05:16.460: E/AndroidRuntime(6053):  at java.util.concurrent.FutureTask$Sync.innerRun(FutureTask.java:305) 
07-02 00:05:16.460: E/AndroidRuntime(6053):  ... 5 more 
07-02 00:05:19.770: D/Process(6053): killProcess, pid=6053 
07-02 00:05:19.800: D/Process(6053): dalvik.system.VMStack.getThreadStackTrace(Native Method) 
07-02 00:05:19.800: D/Process(6053): java.lang.Thread.getStackTrace(Thread.java:599) 
07-02 00:05:19.800: D/Process(6053): android.os.Process.killProcess(Process.java:944) 
07-02 00:05:19.800: D/Process(6053): com.android.internal.os.RuntimeInit$UncaughtHandler.uncaughtException(RuntimeInit.java:108) 
07-02 00:05:19.800: D/Process(6053): java.lang.ThreadGroup.uncaughtException(ThreadGroup.java:693) 
07-02 00:05:19.800: D/Process(6053): java.lang.ThreadGroup.uncaughtException(ThreadGroup.java:690) 
07-02 00:05:20.290: I/dalvikvm-heap(6336): Grow heap (frag case) to 5.287MB for 1536016-byte allocation 
07-02 00:05:20.375: I/dalvikvm-heap(6336): Grow heap (frag case) to 7.890MB for 2731536-byte allocation 
07-02 00:05:20.590: I/MediaPlayer(6336): setLPAflag() in 
07-02 00:05:20.590: I/MediaPlayer(6336): mContext is null, can't getMirrorDisplayStatus!!! 
07-02 00:05:20.590: I/MediaPlayer(6336): setLPAflag() out 
07-02 00:05:20.590: W/MediaPlayer(6336): info/warning (1, 902) 
07-02 00:05:20.635: D/MediaPlayer(6336): Mediaplayer receives message, message type: 200 
07-02 00:05:20.635: I/MediaPlayer(6336): Info (1,902) 
07-02 00:05:20.635: D/MediaPlayer(6336): Mediaplayer receives message, message type: 5 
07-02 00:05:20.635: D/MediaPlayer(6336): Mediaplayer receives message, message type: 1 
07-02 00:05:20.685: E/(6336): file /data/data/com.nvidia.NvCPLSvc/files/driverlist.txt: not found! 
07-02 00:05:20.685: I/(6336): Attempting to load EGL implementation /system/lib//egl/libEGL_tegra_impl 
07-02 00:05:20.735: I/(6336): Loaded EGL implementation /system/lib//egl/libEGL_tegra_impl 
07-02 00:05:20.820: I/(6336): Loading GLESv2 implementation /system/lib//egl/libGLESv2_tegra_impl 
07-02 00:05:21.215: E/SpannableStringBuilder(6336): SPAN_EXCLUSIVE_EXCLUSIVE spans cannot have a zero length 
07-02 00:05:21.215: E/SpannableStringBuilder(6336): SPAN_EXCLUSIVE_EXCLUSIVE spans cannot have a zero length 
07-02 00:05:22.575: E/SpannableStringBuilder(6336): SPAN_EXCLUSIVE_EXCLUSIVE spans cannot have a zero length 
07-02 00:05:22.575: E/SpannableStringBuilder(6336): SPAN_EXCLUSIVE_EXCLUSIVE spans cannot have a zero length

，這是AsyncTank ...

protected String doInBackground(String... arg0) { 

    try { 
     URL url = new URL("http://www.google.com/"); 
     HttpURLConnection conn = (HttpURLConnection) url.openConnection(); 
     conn.setDoInput(true); 
     conn.setDoOutput(true); 
     input = new InputStreamReader(conn.getInputStream()); 
     in =new BufferedReader(input); 
     System.out.println("HELLO"); 
    } catch (MalformedURLException e) { 
     e.printStackTrace(); 
    } catch (IOException e) { 
     e.printStackTrace(); 
    } 
    finally { 
     conn.disconnect(); 
    } 
    return null; 
}

來源

2013-07-01 Merelda

+2

粘貼完整的堆棧跟蹤作爲編輯你的問題。 –

+0

沒有發佈堆棧跟蹤，沒有人能做任何事情，只能猜測。 –

+0

ActivityHi.java第153行有什麼內容？ – DigCamara

回答

1

您發佈的AsyncTask使問題變得明顯。評論153只是隱藏了錯誤。

您在try塊（HttpURLConnection conn = (HttpURLConnection) url.openConnection();）中聲明並指定conn，並在finally中斷開連接。

但是您連接的conn在finally塊中不可見。這意味着你可能有一個具有相同名稱的成員變量。您正試圖斷開連接。

您將得到一個空指針異常因爲成員是null。

首先，我建議將conn更改爲conn2等其他值，以使問題更加明顯（您將在第153行中收到編譯錯誤）。

正確的解決方案是在try塊外部移動conn的聲明和賦值，以便finally塊可見，並根據需要重新調整catch塊。像（我還沒有測試過）：

protected String doInBackground(String... arg0) { 

    try { 
     URL url = new URL("http://www.google.com/"); 
     HttpURLConnection conn = (HttpURLConnection) url.openConnection(); 
     try { 
      conn.setDoInput(true); 
      conn.setDoOutput(true); 
      input = new InputStreamReader(conn.getInputStream()); 
      in =new BufferedReader(input); 
      System.out.println("HELLO"); 
     } 
     finally { 
      conn.disconnect(); 
     } 
    } catch (MalformedURLException e) { 
     e.printStackTrace(); 
    } catch (IOException e) { 
     e.printStackTrace(); 
    } 

    return null; 
}

來源

2013-07-01 22:45:26 Martin

+0

我不得不在最後添加一個}來讓它運行，但這完全有效！ 謝謝！ – Merelda

0

我覺得你的問題是，你正在試圖做到這一點的主要UI Thread，你不能在ICS或Jellybean上做這個，你需要在AsyncTask裏面這樣做，這樣你應該沒問題。

來源

2013-07-01 21:42:01 aehs29

+0

如果引用StrictMode - 它會拋出android.os.NetworkOnMainThreadException，而不是FileNotFoundException。 – manyobject

0

似乎如果你看看at the docs回到developer.android.com你會讓你的代碼工作。

他們的樣品是這樣的：

URL url = new URL("http://www.google.com/"); 
    HttpURLConnection urlConnection = (HttpURLConnection) url.openConnection(); 
    try { 
    InputStream in = new BufferedInputStream(urlConnection.getInputStream()); 
    readStream(in); 
    finally { 
    urlConnection.disconnect(); 
    }

它類似於你的，但你張貼的日誌抱怨

07-02 00:05:16.440: W/System.err(6053): java.io.FileNotFoundException: http://www.google.com/

導致這個空指針異常

07-02 00:05:16.460: E/AndroidRuntime(6053): Caused by: java.lang.NullPointerException

我猜這是這行

conn.setDoInput(true);

來源

2013-07-01 22:27:50 DigCamara

+0

我試圖將該行註釋掉，但即使在添加了readStream（）方法後，它也無濟於事。我的大腦現在太麻煩了，明天早上會回來。感謝您的幫助，非常感謝！ – Merelda

+0

哦，無論如何，它似乎仍然有數據！真的有必要添加.disconnect（）？ – Merelda

+1

是的。在調用斷開連接之前檢查它是否爲空（請參閱我對您的問題的評論回覆）。 – manyobject

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