I just started to work with files today with Android and have been pulling my hair out all day. This throws a FileNotFoundException:
public void writeConfig(){
try {
File file = new File(Environment.getExternalStorageDirectory() + "/" + "AppName", "TimetableConfiguration");
if (!file.mkdirs()) {
P.rint("Couldn't create directory");
}
FileOutputStream fileOutputStream = new FileOutputStream(file);
fileOutputStream.write(getActivity().getSharedPreferences("periods", MODE_PRIVATE).getString("periods", null).getBytes());
fileOutputStream.close();
} catch (FileNotFoundException e) {
P.rint("Didn't find file");
e.printStackTrace();
} catch (IOException e) {
e.printStackTrace();
}
}
Any ideas?
I notice that instead of creating a file, it creates a child folder. Why is it doing this?
Thanks for any help :)
FileNotFoundException: Creates child folder instead of file
Yes. That is what you do.
You first create with mkdirs() a directory with a certain name.
After that you try to create a file with the same name which is impossible as there cannot be two files or directories with the same name.
So have a look and you will find that directory.
Well you had deduced most all yourself already. Now try to understand your code.
if (!file.mkdirs()) {
P.rint("Couldn't create directory");
You will see that printed every time you repeat the code. You should have seen this too. And have told us.
You should only call mkdirs if the directory does not exist yet.
Related
Can someone please tell me if what I'm doing is correct?
File directoryToStore;
directoryToStore = getBaseContext().getExternalFilesDir("MyFiles");
Bitmap b = ThumbnailUtils.createVideoThumbnail(directoryToStore + "/" + SavedVideoName, 3);
File newFile = new File(directoryToStore, SavedVideoName.replace(".mp4", ".jpg"));
FileOutputStream outputStream = null;
try {
outputStream = new FileOutputStream(newFile);
} catch (FileNotFoundException e) {
e.printStackTrace();
}
b.compress(Bitmap.CompressFormat.JPEG, 100, outputStream);
try {
outputStream.close();
} catch (IOException e) {
e.printStackTrace();
}
I'm trying create a thumbnail from a video, but for some the FileOutputStream returns null.
I have checked the path of File newFile = new File(directoryToStore, SavedVideoName.replace(".mp4", ".jpg")); and it returns the correct path.
The video exists at the location I have given and I have permissions. I can't understand why it is gives me a null pointer?
According to this post, new FileOutputStream() will try to create a new file if it doesn't exist already. From the docs:
If the file exists but is a directory rather than a regular file, does not exist but cannot be created, or cannot be opened for any other reason then a FileNotFoundException is thrown.
When you are debugging (at least in Android Studio), if you add a breakpoint and hover over newFile, it shows the file path. However, it doesn't show any details about the file, because the file doesn't (shouldn't) exist yet. You could try newFile.createNewFile() as suggested in the linked post, to confirm you are able to write the file first.
I am trying to open a PDF file when a button is clicked. However I can't seem to get this working when I run my program as a JAR.
Initially, I was using this code:
if(Desktop.isDesktopSupported())
{
try
{
File myFile = new File("src/1. Handel - And the Glory of the Lord.pdf");
Desktop.getDesktop().open(myFile);
}
catch (Exception e)
{
JOptionPane.showMessageDialog(null,e);
}
}
That worked on Netbeans, however it didn't work on the JAR. After research, I found out its because I need to open it using a stream. Meaning I had to make a copy of it as a stream, and open that copy as a File. After looking around on stack overflow, I am now using this code:
try {
String inputPdf = "src/1. Handel - And the Glory of the Lord.pdf";
InputStream manualAsStream = getClass().getClassLoader().getResourceAsStream(inputPdf);
Path tempOutput = Files.createTempFile("1. Handel - And the Glory of the Lord", ".pdf");
tempOutput.toFile().deleteOnExit();
Files.copy(manualAsStream, tempOutput, StandardCopyOption.REPLACE_EXISTING);
File file = new File (tempOutput.toFile().getPath());
if (file.exists())
{
Desktop.getDesktop().open(file);
}
} catch (IOException ex) {
Logger.getLogger(HandelNotes.class.getName()).log(Level.SEVERE, null, ex);
}
This does not even work on Netbeans, whilst on another thread on Stack Exchange, the user said it worked for them.
I am getting a java.lang.NullPointerException error, on this line:
Files.copy(manualAsStream, tempOutput, StandardCopyOption.REPLACE_EXISTING);
Does anyone know what's going wrong, and could someone please tell me how to correct my code?
Thanks,
Rohan
The following program has the purpose of creating a directory,
folderforallofmyjavafiles.mkdir();
and making a file to go inside that directory,
File myfile = new File("C:\\Users\\username\\Desktop\\folderforallofmyjavafiles\\test.txt");
There are two problems though. One is that it says the directory is being created at the desktop, but when checking for the directory, it is not there. Also, when creating the file, I get the exception
ERROR: java.io.FileNotFoundException: folderforallofmyjavafiles\test.txt (The system cannot find the path specified)
Please help me resolve these issues, here is the full code:
package mypackage;
import java.io.*;
public class Createwriteaddopenread {
public static void main(String[] args) {
File folderforallofmyjavafiles = new File("C:\\Users\\username\\Desktop");
try {
folderforallofmyjavafiles.mkdir(); //Creates a directory (mkdirs makes a directory)
if (folderforallofmyjavafiles.isDirectory() == true) {
System.out.println("Folder created at " + "'" + folderforallofmyjavafiles.getPath() + "'");
}
} catch (Exception e) {
System.out.println("Not working...?");
}
File myfile = new File("C:\\Users\\username\\Desktop\\folderforallofmyjavafiles\\test.txt");
//I even tried this:
//File myfile = new File("folderforallofmyjavafiles/test.txt");
//write your name and age through the file
try {
PrintWriter output = new PrintWriter(myfile); //Going to write to myfile
//This may throw an exception, so I always need a try catch when writing to a file
output.println("myname");
output.println("myage");
output.close();
System.out.println("File created");
} catch (IOException e) {
System.out.printf("ERROR: %s\n", e); //e is the IOException
}
}
}
Thank you so much for helping me out, I really appreciate it.
:)
You're creating the Desktop folder in the C:\Users\username folder. If you check the return value of mkdir, you'd notice it's false because the folder already exists.
How would the system know that you want a folder named folderforallofmyjavafiles unless you tell it so?
So, you didn't create the folder, and then you try to create a file in the (nonexistent) folder, and Java tells you the folder doesn't exist.
Agreed that it's a bit obscure, using a FileNotFoundException, but the text does say "The system cannot find the path specified".
Update
You're probably confused about the variable name, so let me say this. The following are all the same:
File folderforallofmyjavafiles = new File("C:\\Users\\username\\Desktop");
folderforallofmyjavafiles.mkdir();
File x = new File("C:\\Users\\username\\Desktop");
x.mkdir();
File folderToCreate = new File("C:\\Users\\username\\Desktop");
folderToCreate.mkdir();
File gobbledygook = new File("C:\\Users\\username\\Desktop");
gobbledygook.mkdir();
new File("C:\\Users\\username\\Desktop").mkdir();
Currently I'm developing a java application to carry out a survey. I want to read/write to a .txt file, creating a .csv to store inputted data. Below is code I have used so far to write data - Of course this makes the JAR file not portable as it has an absolute path.
File file = new File("C:/Files/JavaApp/src/text.text/");
FileWriter fw = null;
BufferedWriter bw = null;
try {
fw = new FileWriter(file, true);
} catch (IOException e) {
System.out.println(e.getMessage());
}
bw = new BufferedWriter(fw);
try {
bw.write("blah" + ",");
} catch (IOException e) {
System.out.println(e.getMessage());
}
try {
bw.newLine();
} catch (IOException e) {
System.out.println(e.getMessage());
}
try {
bw.close();
} catch (IOException e) {
System.out.println(e.getMessage());
}
I have tried several methods such as ClassName.class.getResource("Text.text"); but it will always return a Reflection or a NullPointer error.
I know that writing to a file within the JAR does pose some problems, meaning I would have to point to a file outside to read/write. However I don't know how to preform this in code. I need the JAR file to be completely portable. Even if that means it must be kept within a directory, so the JAR can search for the .txt file within that directory. Or, is there another way?
If anyone can help me out, I would be very grateful.
To read from the Jar file: How to read a file from jar in Java?
The file is an archive file. It is a zip file with a .jar extension. You shouldn't be writing to it. If the jar file has been signed (security projected) you cannot write to it. Changing a single bit in the file will invalidate it.
What you should do is store a default file in Jar and load that to the "user.home" folder if it is not already there.
I have created my sqlite database (employeertest.sql) and puted it in the Assets folder, then run
this code.
Unfortunately in the line getBaseContext().getAssets().open("employeertest") compiler says No such file or directory
try {
String destPath = "/data/data/" + getPackageName() +"/databases";
File f = new File(destPath);
f.mkdirs();
f.createNewFile();
//---copy the db from the assets folder into
// the databases folder---
CopyDB(getBaseContext().getAssets().open("employeertest"),
new FileOutputStream(destPath + "/employeertest"));
} catch (FileNotFoundException e) {
e.printStackTrace();
} catch (IOException e) {
e.printStackTrace();
}
Have you tried
CopyDB(getBaseContext().getAssets().open("employeertest.sql")
instead? Considering the file doesn't exist, I'm assuming the extension is missing and it cannot find the file.
you can use Context.getDatabasePath(String) to retrieve the correct path to the database directory. Please be aware that the directory could also not be there when you try to copy the db from the assets