java.io.FileNotFoundException，打开失败：ENOENT
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java.io.FileNotFoundException, open failed: ENOENT
提问by D. Rao
For some reason I am getting a fileNotFoundExceptionfor both the times I read. Something worth noting is that the Toast prints "File exists!". I used the BufferedReaderat the bottom to test if the content of the file is correct.
出于某种原因，我fileNotFoundException两次阅读都得到了一个。值得注意的是 Toast 会打印“文件存在！”。我使用BufferedReader底部的 来测试文件的内容是否正确。
@Override
public View onCreateView(LayoutInflater inflater, ViewGroup container,
Bundle savedInstanceState) {
View v = inflater.inflate(R.layout.fragment_calendar, container, false);
recipes = new ArrayMap<>();
filename = "calendar_recipes.txt";
bText= (EditText) v.findViewById(R.id.bEditText);
lText= (EditText) v.findViewById(R.id.lEditText);
dText= (EditText) v.findViewById(R.id.dEditText);
cal = (CalendarView) v.findViewById(R.id.calendarView);
date = cal.getDate();
File file = getActivity().getFileStreamPath(filename);
if(file.exists())
{
Toast.makeText(getActivity(), "File exists!", Toast.LENGTH_SHORT).show();
try
{
FileInputStream fileInputStream = new FileInputStream(getActivity().getFilesDir()+filename);
ObjectInputStream objectInputStream = new ObjectInputStream(fileInputStream);
Map recipes = (Map)objectInputStream.readObject();
}
catch(ClassNotFoundException | IOException | ClassCastException e) {
e.printStackTrace();
}
}
else
{
Toast.makeText(getActivity(), "File does not exist!!", Toast.LENGTH_SHORT).show();
file = new File(getActivity().getFilesDir(), filename);
}
try {
BufferedReader in = new BufferedReader(new FileReader(filename));
String line;
while ((line = in.readLine()) != null) {
System.out.println(line);
}
in.close();
}
catch (IOException e) {
e.printStackTrace();
}
Logcat...
日志...
03-24 23:54:57.626 14059-14067/com.stringcheese.recipez.recip_ez W/art: Suspending all threads took: 7.202ms
03-24 23:54:58.409 14059-14059/com.stringcheese.recipez.recip_ez W/System.err: java.io.FileNotFoundException: /data/data/com.stringcheese.recipez.recip_ez/filescalendar_recipes.txt: open failed: ENOENT (No such file or directory)
03-24 23:54:58.410 14059-14059/com.stringcheese.recipez.recip_ez W/System.err: at libcore.io.IoBridge.open(IoBridge.java:456)
03-24 23:54:58.410 14059-14059/com.stringcheese.recipez.recip_ez W/System.err: at java.io.FileInputStream.<init>(FileInputStream.java:76)
03-24 23:54:58.410 14059-14059/com.stringcheese.recipez.recip_ez W/System.err: at java.io.FileInputStream.<init>(FileInputStream.java:103)
03-24 23:54:58.410 14059-14059/com.stringcheese.recipez.recip_ez W/System.err: at com.stringcheese.recipez.recip_ez.CalendarFragment.onCreateView(CalendarFragment.java:80)
03-24 23:54:58.410 14059-14059/com.stringcheese.recipez.recip_ez W/System.err: at android.support.v4.app.Fragment.performCreateView(Fragment.java:1974)
03-24 23:54:58.410 14059-14059/com.stringcheese.recipez.recip_ez W/System.err: at android.support.v4.app.FragmentManagerImpl.moveToState(FragmentManager.java:1067)
03-24 23:54:58.410 14059-14059/com.stringcheese.recipez.recip_ez W/System.err: at android.support.v4.app.FragmentManagerImpl.moveToState(FragmentManager.java:1252)
03-24 23:54:58.410 14059-14059/com.stringcheese.recipez.recip_ez W/System.err: at android.support.v4.app.BackStackRecord.run(BackStackRecord.java:738)
03-24 23:54:58.410 14059-14059/com.stringcheese.recipez.recip_ez W/System.err: at android.support.v4.app.FragmentManagerImpl.execPendingActions(FragmentManager.java:1617)
03-24 23:54:58.410 14059-14059/com.stringcheese.recipez.recip_ez W/System.err: at android.support.v4.app.FragmentController.execPendingActions(FragmentController.java:339)
03-24 23:54:58.410 14059-14059/com.stringcheese.recipez.recip_ez W/System.err: at android.support.v4.app.FragmentActivity.onStart(FragmentActivity.java:602)
03-24 23:54:58.410 14059-14059/com.stringcheese.recipez.recip_ez W/System.err: at android.app.Instrumentation.callActivityOnStart(Instrumentation.java:1259)
03-24 23:54:58.410 14059-14059/com.stringcheese.recipez.recip_ez W/System.err: at android.app.Activity.performStart(Activity.java:6026)
03-24 23:54:58.410 14059-14059/com.stringcheese.recipez.recip_ez W/System.err: at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2302)
03-24 23:54:58.410 14059-14059/com.stringcheese.recipez.recip_ez W/System.err: at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:2413)
03-24 23:54:58.410 14059-14059/com.stringcheese.recipez.recip_ez W/System.err: at android.app.ActivityThread.access0(ActivityThread.java:155)
03-24 23:54:58.410 14059-14059/com.stringcheese.recipez.recip_ez W/System.err: at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1317)
03-24 23:54:58.410 14059-14059/com.stringcheese.recipez.recip_ez W/System.err: at android.os.Handler.dispatchMessage(Handler.java:102)
03-24 23:54:58.410 14059-14059/com.stringcheese.recipez.recip_ez W/System.err: at android.os.Looper.loop(Looper.java:135)
03-24 23:54:58.410 14059-14059/com.stringcheese.recipez.recip_ez W/System.err: at android.app.ActivityThread.main(ActivityThread.java:5343)
03-24 23:54:58.410 14059-14059/com.stringcheese.recipez.recip_ez W/System.err: at java.lang.reflect.Method.invoke(Native Method)
03-24 23:54:58.410 14059-14059/com.stringcheese.recipez.recip_ez W/System.err: at java.lang.reflect.Method.invoke(Method.java:372)
03-24 23:54:58.411 14059-14059/com.stringcheese.recipez.recip_ez W/System.err: at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:907)
03-24 23:54:58.411 14059-14059/com.stringcheese.recipez.recip_ez W/System.err: at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:702)
03-24 23:54:58.411 14059-14059/com.stringcheese.recipez.recip_ez W/System.err: Caused by: android.system.ErrnoException: open failed: ENOENT (No such file or directory)
03-24 23:54:58.411 14059-14059/com.stringcheese.recipez.recip_ez W/System.err: at libcore.io.Posix.open(Native Method)
03-24 23:54:58.411 14059-14059/com.stringcheese.recipez.recip_ez W/System.err: at libcore.io.BlockGuardOs.open(BlockGuardOs.java:186)
03-24 23:54:58.411 14059-14059/com.stringcheese.recipez.recip_ez W/System.err: at libcore.io.IoBridge.open(IoBridge.java:442)
03-24 23:54:58.411 14059-14059/com.stringcheese.recipez.recip_ez W/System.err: ... 23 more
回答by F43nd1r
getFilesDirreturns a File object. If you call onString on it (which you do implicitly), it returns its path. The path is notending with a slash if the file is a directory, so getActivity().getFilesDir()+filenamewill result in something like "/data/data/com.yourapp/filescalendar_recipes.txt".
getFilesDir返回一个 File 对象。如果您对其调用 onString （您隐式执行），它将返回其路径。如果文件是目录，则路径不以斜杠结尾，因此getActivity().getFilesDir()+filename将导致类似"/data/data/com.yourapp/filescalendar_recipes.txt".
You can either use getActivity().getFilesDir()+File.separator+filename, or just call new FileInputStream(file).
您可以使用getActivity().getFilesDir()+File.separator+filename，也可以直接调用new FileInputStream(file)。
回答by LuisFMorales
You have already created a Fileinstance with File file = getActivity().getFileStreamPath(filename);which is the instance that you are checking with the file.exists()method. Then you are trying to read another thing with the FileInputStream. You should try FileInputStream fileInputStream = new FileInputStream(file);. With that you are creating your stream with the file that you already checked.
您已经创建了一个File实例，File file = getActivity().getFileStreamPath(filename);该实例是您使用该file.exists()方法检查的实例。然后你试图用FileInputStream. 你应该试试FileInputStream fileInputStream = new FileInputStream(file);。这样您就可以使用已经检查过的文件创建流。
回答by Mohd Zaid
I was Getting the same error. ThisAnswer worked for me.
我得到了同样的错误。 这个答案对我有用。
You just have to add one line in your manifest like this:
您只需要在清单中添加一行，如下所示：
<application
android:allowBackup="true"
android:icon="@mipmap/ic_launcher"
android:requestLegacyExternalStorage="true" //Add this Line
android:label="@string/app_name">
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