else if (v.getId() == R.id.update) {
        StrictMode.ThreadPolicy policy = new StrictMode.ThreadPolicy.Builder().permitAll().build();
        StrictMode.setThreadPolicy(policy);
        try {
            URL url = new URL("http://darkliteempire.gaming.multiplay.co.uk/testdownload.txt");
            //create the new connection
            HttpURLConnection urlConnection = (HttpURLConnection) url.openConnection();
            //set up some things on the connection
            urlConnection.setRequestMethod("GET");
            urlConnection.setDoOutput(true);
            //and connect!
            urlConnection.connect();
            //set the path where we want to save the file
            //in this case, going to save it on the root directory of the
            //sd card.
            File SDCardRoot = new File("/sdcard/"+"download/");
            //create a new file, specifying the path, and the filename
            //which we want to save the file as.
            File file = new File(SDCardRoot,"test.txt");
            //this will be used to write the downloaded data into the file we created
            FileOutputStream fileOutput = new FileOutputStream(file);
            //this will be used in reading the data from the internet
            InputStream inputStream = urlConnection.getInputStream();
            //this is the total size of the file
            int totalSize = urlConnection.getContentLength();
            //variable to store total downloaded bytes
            int downloadedSize = 0;
            //create a buffer...
            byte[] buffer = new byte[1024];
            int bufferLength = 0; //used to store a temporary size of the buffer
            //now, read through the input buffer and write the contents to the file
            while ( (bufferLength = inputStream.read(buffer)) > 0 ) 
            {
            //add the data in the buffer to the file in the file output stream (the file on the sd card
            fileOutput.write(buffer, 0, bufferLength);
            //add up the size so we know how much is downloaded
            downloadedSize += bufferLength;
            int progress=(int)(downloadedSize*100/totalSize);
            //this is where you would do something to report the prgress, like this maybe
            //updateProgress(downloadedSize, totalSize);
            }
            //close the output stream when done
            fileOutput.close();
        } catch (MalformedURLException e1) {
            // TODO Auto-generated catch block
            e1.printStackTrace();
        } catch (ProtocolException e1) {
            // TODO Auto-generated catch block
            e1.printStackTrace();
        } catch (FileNotFoundException e1) {
            // TODO Auto-generated catch block
            e1.printStackTrace();
        } catch (IOException e1) {
            // TODO Auto-generated catch block
            e1.printStackTrace();
        }
此代码不断出现 FileNotFoundException,但文件在那里,如果您按照 url 可以看到它。
它必须以特定方式托管吗?还是我得到它的方式有问题
编辑:这是 logcat 消息
12-14 22:29:19.890: W/System.err(24557): java.io.FileNotFoundException:     http://darkliteempire.gaming.multiplay.co.uk/testdownload.txt
12-14 22:29:19.890: W/System.err(24557):    at libcore.net.http.HttpURLConnectionImpl.getInputStream(HttpURLConnectionImpl.java:177)
12-14 22:29:19.890: W/System.err(24557):    at com.MasterZangetsu.kentrocksoc.MainActivity.onClick(MainActivity.java:99)
12-14 22:29:19.890: W/System.err(24557):    at android.view.View.performClick(View.java:3591)
12-14 22:29:19.890: W/System.err(24557):    at android.view.View$PerformClick.run(View.java:14263)
12-14 22:29:19.895: W/System.err(24557):    at android.os.Handler.handleCallback(Handler.java:605)
12-14 22:29:19.895: W/System.err(24557):    at android.os.Handler.dispatchMessage(Handler.java:92)
12-14 22:29:19.895: W/System.err(24557):    at android.os.Looper.loop(Looper.java:137)
12-14 22:29:19.895: W/System.err(24557):    at android.app.ActivityThread.main(ActivityThread.java:4507)
12-14 22:29:19.895: W/System.err(24557):    at java.lang.reflect.Method.invokeNative(Native Method)
12-14 22:29:19.895: W/System.err(24557):    at java.lang.reflect.Method.invoke(Method.java:511)
12-14 22:29:19.895: W/System.err(24557):    at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:790)
12-14 22:29:19.895: W/System.err(24557):    at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:557)
12-14 22:29:19.895: W/System.err(24557):    at dalvik.system.NativeStart.main(Native Method)
12-14 22:29:20.170: W/WifiStateTracker(2010): getNetworkInfo : NetworkInfo: type: WIFI[], state: DISCONNECTED/DISCONNECTED, reason: (unspecified), extra: (none), roaming: false, failover: false, isAvailable: false