我正在尝试从网址下载pdf，然后保存并阅读它。但是当我尝试阅读它时，我收到错误java.io.IOException: /storage/emulated/0/pdf/menu.pdf not found as file or resource.。有什么想法吗？
这是我的Downloader类：
public class Downloader {
public static void DownloadFile(String fileURL, File directory) {
try {
FileOutputStream f = new FileOutputStream(directory);
URL u = new URL(fileURL);
HttpURLConnection c = (HttpURLConnection) u.openConnection();
c.setRequestMethod("GET");
c.setDoOutput(true);
c.connect();
InputStream in = c.getInputStream();
byte[] buffer = new byte[1024];
int len1 = 0;
while ((len1 = in.read(buffer)) > 0) {
f.write(buffer, 0, len1);
}
f.close();
} catch (Exception e) {
e.printStackTrace();
}
}
}
下载并阅读pdf的行：
String extStorageDirectory = Environment.getExternalStorageDirectory().getAbsolutePath()
.toString();
File folder = new File(extStorageDirectory, "pdf");
folder.mkdir();
File file = new File(folder, "menu.pdf");
try {
file.createNewFile();
} catch (IOException e1) {
e1.printStackTrace();
}
Downloader.DownloadFile("http://webdfd.mines-ales.fr/restau/Menu_Semaine.pdf", file);
PdfReader reader = new PdfReader(Environment.getExternalStorageDirectory().getAbsolutePath()+"/pdf/menu.pdf");
这是错误：
05-02 13:59:01.138 16747-16747/? I/art: Not late-enabling -Xcheck:jni (already on)
05-02 13:59:01.139 16747-16747/? W/art: Unexpected CPU variant for X86 using defaults: x86
05-02 13:59:01.676 16747-16747/com.example.yohannmbp.ematoufaire I/InstantRun: starting instant run server: is main process
05-02 13:59:01.868 16747-16747/com.example.yohannmbp.ematoufaire W/art: Before Android 4.1, method android.graphics.PorterDuffColorFilter android.support.graphics.drawable.VectorDrawableCompat.updateTintFilter(android.graphics.PorterDuffColorFilter, android.content.res.ColorStateList, android.graphics.PorterDuff$Mode) would have incorrectly overridden the package-private method in android.graphics.drawable.Drawable
05-02 13:59:02.440 16747-16787/com.example.yohannmbp.ematoufaire D/NetworkSecurityConfig: No Network Security Config specified, using platform default
05-02 13:59:02.783 16747-16795/com.example.yohannmbp.ematoufaire I/OpenGLRenderer: Initialized EGL, version 1.4
05-02 13:59:02.783 16747-16795/com.example.yohannmbp.ematoufaire D/OpenGLRenderer: Swap behavior 1
05-02 13:59:02.783 16747-16795/com.example.yohannmbp.ematoufaire W/OpenGLRenderer: Failed to choose config with EGL_SWAP_BEHAVIOR_PRESERVED, retrying without...
05-02 13:59:02.783 16747-16795/com.example.yohannmbp.ematoufaire D/OpenGLRenderer: Swap behavior 0
05-02 13:59:03.029 16747-16747/com.example.yohannmbp.ematoufaire W/art: Before Android 4.1, method int android.support.v7.widget.ListViewCompat.lookForSelectablePosition(int, boolean) would have incorrectly overridden the package-private method in android.widget.ListView
05-02 13:59:11.011 16747-16747/com.example.yohannmbp.ematoufaire W/System.err: java.io.IOException: No such file or directory
05-02 13:59:11.012 16747-16747/com.example.yohannmbp.ematoufaire W/System.err: at java.io.UnixFileSystem.createFileExclusively0(Native Method)
05-02 13:59:11.012 16747-16747/com.example.yohannmbp.ematoufaire W/System.err: at java.io.UnixFileSystem.createFileExclusively(UnixFileSystem.java:280)
05-02 13:59:11.012 16747-16747/com.example.yohannmbp.ematoufaire W/System.err: at java.io.File.createNewFile(File.java:948)
05-02 13:59:11.012 16747-16747/com.example.yohannmbp.ematoufaire W/System.err: at com.example.yohannmbp.ematoufaire.MenuFragment.onCreateView(MenuFragment.java:106)
05-02 13:59:11.012 16747-16747/com.example.yohannmbp.ematoufaire W/System.err: at android.support.v4.app.Fragment.performCreateView(Fragment.java:2192)
05-02 13:59:11.012 16747-16747/com.example.yohannmbp.ematoufaire W/System.err: at android.support.v4.app.FragmentManagerImpl.moveToState(FragmentManager.java:1299)
05-02 13:59:11.012 16747-16747/com.example.yohannmbp.ematoufaire W/System.err: at android.support.v4.app.FragmentManagerImpl.moveFragmentToExpectedState(FragmentManager.java:1528)
05-02 13:59:11.012 16747-16747/com.example.yohannmbp.ematoufaire W/System.err: at android.support.v4.app.FragmentManagerImpl.moveToState(FragmentManager.java:1595)
05-02 13:59:11.012 16747-16747/com.example.yohannmbp.ematoufaire W/System.err: at android.support.v4.app.BackStackRecord.executeOps(BackStackRecord.java:758)
05-02 13:59:11.012 16747-16747/com.example.yohannmbp.ematoufaire W/System.err: at android.support.v4.app.FragmentManagerImpl.executeOps(FragmentManager.java:2363)
05-02 13:59:11.012 16747-16747/com.example.yohannmbp.ematoufaire W/System.err: at android.support.v4.app.FragmentManagerImpl.executeOpsTogether(FragmentManager.java:2149)
05-02 13:59:11.012 16747-16747/com.example.yohannmbp.ematoufaire W/System.err: at android.support.v4.app.FragmentManagerImpl.optimizeAndExecuteOps(FragmentManager.java:2103)
05-02 13:59:11.012 16747-16747/com.example.yohannmbp.ematoufaire W/System.err: at android.support.v4.app.FragmentManagerImpl.execPendingActions(FragmentManager.java:2013)
05-02 13:59:11.012 16747-16747/com.example.yohannmbp.ematoufaire W/System.err: at android.support.v4.app.FragmentManagerImpl$1.run(FragmentManager.java:710)
05-02 13:59:11.012 16747-16747/com.example.yohannmbp.ematoufaire W/System.err: at android.os.Handler.handleCallback(Handler.java:751)
05-02 13:59:11.013 16747-16747/com.example.yohannmbp.ematoufaire W/System.err: at android.os.Handler.dispatchMessage(Handler.java:95)
05-02 13:59:11.013 16747-16747/com.example.yohannmbp.ematoufaire W/System.err: at android.os.Looper.loop(Looper.java:154)
05-02 13:59:11.013 16747-16747/com.example.yohannmbp.ematoufaire W/System.err: at android.app.ActivityThread.main(ActivityThread.java:6119)
05-02 13:59:11.013 16747-16747/com.example.yohannmbp.ematoufaire W/System.err: at java.lang.reflect.Method.invoke(Native Method)
05-02 13:59:11.013 16747-16747/com.example.yohannmbp.ematoufaire W/System.err: at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:886)
05-02 13:59:11.013 16747-16747/com.example.yohannmbp.ematoufaire W/System.err: at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:776)
05-02 13:59:11.015 16747-16747/com.example.yohannmbp.ematoufaire W/System.err: java.io.FileNotFoundException: /storage/emulated/0/pdf/menu.pdf (No such file or directory)
05-02 13:59:11.015 16747-16747/com.example.yohannmbp.ematoufaire W/System.err: at java.io.FileOutputStream.open(Native Method)
05-02 13:59:11.016 16747-16747/com.example.yohannmbp.ematoufaire W/System.err: at java.io.FileOutputStream.<init>(FileOutputStream.java:221)
05-02 13:59:11.016 16747-16747/com.example.yohannmbp.ematoufaire W/System.err: at java.io.FileOutputStream.<init>(FileOutputStream.java:169)
05-02 13:59:11.016 16747-16747/com.example.yohannmbp.ematoufaire W/System.err: at com.example.yohannmbp.ematoufaire.Downloader.DownloadFile(Downloader.java:18)
05-02 13:59:11.016 16747-16747/com.example.yohannmbp.ematoufaire W/System.err: at com.example.yohannmbp.ematoufaire.MenuFragment.onCreateView(MenuFragment.java:110)
05-02 13:59:11.017 16747-16747/com.example.yohannmbp.ematoufaire W/System.err: at android.support.v4.app.Fragment.performCreateView(Fragment.java:2192)
05-02 13:59:11.017 16747-16747/com.example.yohannmbp.ematoufaire W/System.err: at android.support.v4.app.FragmentManagerImpl.moveToState(FragmentManager.java:1299)
05-02 13:59:11.017 16747-16747/com.example.yohannmbp.ematoufaire W/System.err: at android.support.v4.app.FragmentManagerImpl.moveFragmentToExpectedState(FragmentManager.java:1528)
05-02 13:59:11.017 16747-16747/com.example.yohannmbp.ematoufaire W/System.err: at android.support.v4.app.FragmentManagerImpl.moveToState(FragmentManager.java:1595)
05-02 13:59:11.018 16747-16747/com.example.yohannmbp.ematoufaire W/System.err: at android.support.v4.app.BackStackRecord.executeOps(BackStackRecord.java:758)
05-02 13:59:11.018 16747-16747/com.example.yohannmbp.ematoufaire W/System.err: at android.support.v4.app.FragmentManagerImpl.executeOps(FragmentManager.java:2363)
05-02 13:59:11.018 16747-16747/com.example.yohannmbp.ematoufaire W/System.err: at android.support.v4.app.FragmentManagerImpl.executeOpsTogether(FragmentManager.java:2149)
05-02 13:59:11.018 16747-16747/com.example.yohannmbp.ematoufaire W/System.err: at android.support.v4.app.FragmentManagerImpl.optimizeAndExecuteOps(FragmentManager.java:2103)
05-02 13:59:11.018 16747-16747/com.example.yohannmbp.ematoufaire W/System.err: at android.support.v4.app.FragmentManagerImpl.execPendingActions(FragmentManager.java:2013)
05-02 13:59:11.018 16747-16747/com.example.yohannmbp.ematoufaire W/System.err: at android.support.v4.app.FragmentManagerImpl$1.run(FragmentManager.java:710)
05-02 13:59:11.018 16747-16747/com.example.yohannmbp.ematoufaire W/System.err: at android.os.Handler.handleCallback(Handler.java:751)
05-02 13:59:11.018 16747-16747/com.example.yohannmbp.ematoufaire W/System.err: at android.os.Handler.dispatchMessage(Handler.java:95)
05-02 13:59:11.018 16747-16747/com.example.yohannmbp.ematoufaire W/System.err: at android.os.Looper.loop(Looper.java:154)
05-02 13:59:11.018 16747-16747/com.example.yohannmbp.ematoufaire W/System.err: at android.app.ActivityThread.main(ActivityThread.java:6119)
05-02 13:59:11.018 16747-16747/com.example.yohannmbp.ematoufaire W/System.err: at java.lang.reflect.Method.invoke(Native Method)
05-02 13:59:11.018 16747-16747/com.example.yohannmbp.ematoufaire W/System.err: at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:886)
05-02 13:59:11.018 16747-16747/com.example.yohannmbp.ematoufaire W/System.err: at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:776)
05-02 13:59:11.088 16747-16752/com.example.yohannmbp.ematoufaire I/art: Do partial code cache collection, code=30KB, data=29KB
05-02 13:59:11.089 16747-16752/com.example.yohannmbp.ematoufaire I/art: After code cache collection, code=23KB, data=25KB
05-02 13:59:11.089 16747-16752/com.example.yohannmbp.ematoufaire I/art: Increasing code cache capacity to 128KB
05-02 13:59:11.127 16747-16747/com.example.yohannmbp.ematoufaire I/System.out: java.io.IOException: /storage/emulated/0/pdf/menu.pdf not found as file or resource.
答案 0 :(得分：1)
private class DownloadTask extends AsyncTask<String, Integer, String> {
private Context context;
private PowerManager.WakeLock mWakeLock;
public DownloadTask(Context context) {
this.context = context;
}
**strong text** @Override
protected String doInBackground(String... sUrl) {
InputStream input = null;
OutputStream output = null;
HttpURLConnection connection = null;
try {
URL url = new URL(AppConstant.BASE_URL + URLEncoder.encode(sUrl[0], "UTF-8"));
connection = (HttpURLConnection) url.openConnection();
connection.connect();
// expect HTTP 200 OK, so we don't mistakenly save error report
// instead of the file
if (connection.getResponseCode() != HttpURLConnection.HTTP_OK) {
return "Server returned HTTP " + connection.getResponseCode()
+ " " + connection.getResponseMessage();
}
// this will be useful to display download percentage
// might be -1: server did not report the length
int fileLength = connection.getContentLength();
// download the file
fileName = sUrl[0].substring(sUrl[0].lastIndexOf("/") + 1,
sUrl[0].length());
input = connection.getInputStream();
output = new FileOutputStream(Environment.getExternalStoragePublicDirectory(Environment.DIRECTORY_DOWNLOADS) + "/" + fileName);
byte data[] = new byte[4096];
long total = 0;
int count;
while ((count = input.read(data)) != -1) {
// allow canceling with back button
if (isCancelled()) {
input.close();
return null;
}
total += count;
// publishing the progress....
if (fileLength > 0) // only if total length is known
publishProgress((int) (total * 100 / fileLength));
output.write(data, 0, count);
}
} catch (Exception e) {
return e.toString();
} finally {
try {
if (output != null)
output.close();
if (input != null)
input.close();
} catch (IOException ignored) {
}
if (connection != null)
connection.disconnect();
}
return null;
}
@Override
protected void onPreExecute() {
super.onPreExecute();
// take CPU lock to prevent CPU from going off if the user
// presses the power button during download
PowerManager pm = (PowerManager) context.getSystemService(Context.POWER_SERVICE);
mWakeLock = pm.newWakeLock(PowerManager.PARTIAL_WAKE_LOCK,
getClass().getName());
mWakeLock.acquire();
mProgressDialog.show();
}
@Override
protected void onProgressUpdate(Integer... progress) {
super.onProgressUpdate(progress);
mProgressDialog.setIndeterminate(false);
mProgressDialog.setMax(100);
mProgressDialog.setProgress(progress[0]);
}
@Override
protected void onPostExecute(String result) {
mWakeLock.release();
mProgressDialog.dismiss();
if (result != null)
Toast.makeText(context, "Download error: File is not Found.", Toast.LENGTH_LONG).show();
else {
new AlertDialog.Builder(context)
//.setTitle("Delete entry")
.setMessage("File Downloaded Successfully. Do you want to open it?")
.setPositiveButton("Open", new DialogInterface.OnClickListener() {
public void onClick(DialogInterface dialog, int which) {
try {
File file = new File(Environment.getExternalStoragePublicDirectory(Environment.DIRECTORY_DOWNLOADS) + "/" + fileName);
MimeTypeMap map = MimeTypeMap.getSingleton();
String ext = MimeTypeMap.getFileExtensionFromUrl(file.getName());
String type = map.getMimeTypeFromExtension(ext);
if (type == null)
type = "*/*";
Intent intent = new Intent(Intent.ACTION_VIEW);
Uri data = Uri.fromFile(file);
intent.setDataAndType(data, type);
context.startActivity(intent);
} catch (ActivityNotFoundException e) {
Toast.makeText(context, "There is no app registered to handle the type of file selected.", Toast.LENGTH_SHORT).show();
}
}
})
.setNegativeButton("Cancel", new DialogInterface.OnClickListener() {
public void onClick(DialogInterface dialog, int which) {
// do nothing
}
})
.setIcon(android.R.drawable.ic_dialog_alert)
.show();
Toast.makeText(context, "File downloaded", Toast.LENGTH_SHORT).show();
}
}
}
答案 1 :(得分：0)
试试这个
downloadTask = new DownloadTask();
downloadTask.execute("http://webdfd.mines-ales.fr/restau/Menu_Semaine.pdf", "", "");
private class DownloadTask extends AsyncTask<String, Integer, String> {
@Override
protected void onPreExecute() {
super.onPreExecute();
ll_view.setVisibility(View.VISIBLE);
}
@Override
protected String doInBackground(String... sUrl) {
InputStream input = null;
OutputStream output = null;
HttpURLConnection connection = null;
try {
URL url = new URL(sUrl[0]);
connection = (HttpURLConnection) url.openConnection();
connection.connect();
// expect HTTP 200 OK, so we don't mistakenly save error report
// instead of the file
if (connection.getResponseCode() != HttpURLConnection.HTTP_OK) {
return "Server returned HTTP " + connection.getResponseCode()
+ " " + connection.getResponseMessage();
}
// this will be useful to display download percentage
// might be -1: server did not report the length
int fileLength = connection.getContentLength();
// download the file
input = connection.getInputStream();
File sourcePath = Environment.getExternalStorageDirectory();
File path = new File(sourcePath + "/" + Constants.DIR_NAME + "/");
path.mkdir();
File file = new File(path, "/ecute("http://webdfd.mines-ales.fr/restau/Menu_Semaine.pdf");
if (file.exists()) {
file.delete();
}
output = new FileOutputStream(file);
byte data[] = new byte[4096];
long total = 0;
int count;
while ((count = input.read(data)) != -1) {
// allow canceling with back button
if (isCancelled()) {
input.close();
return null;
}
total += count;
// publishing the progress....
if (fileLength > 0) // only if total length is known
publishProgress((int) (total * 100 / fileLength));
output.write(data, 0, count);
}
} catch (Exception e) {
return e.toString();
} finally {
try {
if (output != null)
output.close();
if (input != null)
input.close();
} catch (IOException ignored) {
}
if (connection != null)
connection.disconnect();
}
return null;
}
@Override
protected void onPostExecute(String s) {
super.onPostExecute(s);
ll_view.setVisibility(View.GONE);
}
@Override
protected void onProgressUpdate(final Integer... values) {
super.onProgressUpdate(values);
// Log.e("progressing", "" + values[0]);
// edt_search.setText("" + values[0]);
// new Thread(new Runnable() {
// public void run() {
progressBar.setProgress(values[0]);
// tv_downloading.setText("" + values[0] + "%");
// }
// }).start();
}
@Override
protected void onCancelled(String s) {
super.onCancelled(s);
}
@Override
protected void onCancelled() {
super.onCancelled();
}
}
如果您的目标和编译sdk高于lolipop，那么您必须在下载this链接之前添加请求权限代码并读取和写入所需的外部存储权限