Directory not showing up in desktop, and file not being created? - java

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();

Related

FileNotFoundException: Creates child folder instead of file

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.

Creating temporary file and rename to actual file

I am trying to create a temporary file and then rename it to a usable file. The temp file is getting created in %temp% but not getting renamed:-
static void writeFile() {
try {
File tempFile = File.createTempFile("TEMP_FAILED_MASTER", "");
PrintWriter pw = new PrintWriter(tempFile);
for (String record : new String[] {"a","b"}) {
pw.println(record);
}
pw.flush();
pw.close();
System.out.println(tempFile.getAbsolutePath());
File errFile = new File("C:/bar.txt");
tempFile.renameTo(errFile);
System.out.println(errFile.getAbsolutePath());
System.out.println("Check!");
} catch (Exception e) {
e.printStackTrace();
}
}

There are a few reasons why a rename can fail. The common ones are:
You don't have write permission for the source or destination directory.
The file you are renaming is open (on Windows)
You are attempting to rename across different file systems.
It can be difficult to diagnose these (and other) failure reasons if you are using File.renameTo because all you get is a boolean return value.
I recommend using Files.move instead. It can cope with moving files between file systems, and will throw an exception if the file cannot be renamed.

Why can't I find my File?

I'm trying to open a CSV file name "logger.csv" which I have saved in the source folder itself.
public static void main(String[] args) {
String filename = "logger.csv";
File motor_readings = new File(filename);
try {
Scanner inputStream = new Scanner(motor_readings);
while (inputStream.hasNext()){
System.out.println(inputStream.next());
}
inputStream.close();
} catch (FileNotFoundException e) {
System.out.println("Error: File not found!");
}
}
However, this keeps on giving me a "File not found" error.

If you use relative pathing as you are right now - the file needs to exist in the project root, not in the directory of the java file.
Consider this hierarchy:
project/
src/main/java
file.java
logger.csv
new File("logger.csv") will not work.
project/
logger.csv
src/main/java
file.java
new File("logger.csv") will now work. (notice, the file is adjacent to the src directory.)

Put the file on level up. In the main folder of the project.

To see where the file is expected update the code in your catch clause to:
System.out.println("Error: File not found: " + motor_readings.getAbsolutePath());
Put it there and be sure to refresh your workspace in Eclipse so that the file can be seen.

File turns to folder

So, I'm having a hard time with files. I've used files before, but this time they are being a pain.
public SaveFile(File newFile)
{
this.file = newFile;
boolean first = false;
if(!file.exists()){
file.mkdir();
first = true;
}
if(file.isDirectory()){
throw new IllegalStateException("Save file can not be a folder");
}
if(file.getName().equalsIgnoreCase("current")){
first = false;
}
this.config = YamlConfiguration.loadConfiguration(this.file);
String name = file.getName();
name = name.substring(0, name.lastIndexOf("."));
if(first){
config.set("name", name);
config.set("health", 20.0F);
config.set("level", 0);
}
try {
config.save(file);
} catch (IOException e) {
e.printStackTrace();
}
}
When I create one save file, it works no problem. I can view and edit the file, which is great. However, if I attempt to create a second SaveFile, it turns the NEW file into a folder and throws an IllegalStateException
This is how it looks:
public static void main(String[] args){
SaveFile robert = new SaveFile(new File(SaveFile.getSaveFolder(), "Robert.save"));
SaveFile james = new SaveFile(new File(SaveFile.getSaveFolder(), "James.save");
}
The SaveFile robert is created, and looks like its supposed to.
The SaveFile james is created as a folder, and throws an IllegalStateException

Apparently you are trying to create a file in a parent directory and you want to check whether the parent directory exists and create it first if required.
You need to get the parent of the file you pass which is the directory you may want to create using File#getParentFile(). This method returns a File object of witch you have to call File#mkdirs().
You could proceed like this for example:
public void saveFile(File newFile)
{
File file = newFile;
if(! file.exists()){
File dir = file.getParentFile();
if(! dir.exists()) {
if(dir.mkdirs()) {
System.out.println("parent directory "
+ dir.getPath() + " created");
}
if(! dir.isDirectory()){
throw new IllegalStateException("Unable to create directory "
+ dir.getPath());
}
}
} else {
if(file.isDirectory()){
throw new IllegalStateException("Save file can not be a folder");
}
}
// ...
System.out.println("Save file " + file.getPath() + " created");
}

I think you're problem is here, as noted in my code comments:
boolean first = false;
if(!file.exists()){
// the following line is turning the file into a directory if the file
// doesn't already exist
file.mkdir();
first = true;
}
// now you are checking if the directory you just created is a directory
// (this will, of course, be true) and thus throw the exception
if(file.isDirectory()){
throw new IllegalStateException("Save file can not be a folder");
}
So it looks like "Robert.save" exists, and thus works, but "James.save" doesn't so it get created as a directory.

It has something to do with this line of code:
file.mkdir();
,which makes a directory out of the path of the File object you pass as parameter. So, if none of the files (Robert.save and James.save) exist before the execution, it will create two directories named /your/path/Robert.save and /your/path/James.save.
The fact that it only creates one directory may only be caused by the fact that Robert.save might already exist before you execute your code. So the mkDir method won't be called because the following condition isn't validated:
if(!file.exists())

How to create a directory in Java?

How do I create Directory/folder?
Once I have tested System.getProperty("user.home");
I have to create a directory (directory name "new folder" ) if and only if new folder does not exist.

new File("/path/directory").mkdirs();
Here "directory" is the name of the directory you want to create/exist.

After ~7 year, I will update it to better approach which is suggested by Bozho.
File theDir = new File("/path/directory");
if (!theDir.exists()){
theDir.mkdirs();
}

With Java 7, you can use Files.createDirectories().
For instance:
Files.createDirectories(Paths.get("/path/to/directory"));

You can try FileUtils#forceMkdir
FileUtils.forceMkdir("/path/directory");
This library have a lot of useful functions.

mkdir vs mkdirs
If you want to create a single directory use mkdir
new File("/path/directory").mkdir();
If you want to create a hierarchy of folder structure use mkdirs
new File("/path/directory").mkdirs();

Create a single directory.
new File("C:\\Directory1").mkdir();
Create a directory named “Directory2 and all its sub-directories “Sub2″ and “Sub-Sub2″ together.
new File("C:\\Directory2\\Sub2\\Sub-Sub2").mkdirs()
Source: this perfect tutorial , you find also an example of use.

For java 7 and up:
Path path = Paths.get("/your/path/string");
Files.createDirectories(path);
It seems unnecessary to check for existence of the dir or file before creating, from createDirectories javadocs:
Creates a directory by creating all nonexistent parent directories first. Unlike the createDirectory method, an exception is not thrown if the directory could not be created because it already exists.
The attrs parameter is optional file-attributes to set atomically when creating the nonexistent directories. Each file attribute is identified by its name. If more than one attribute of the same name is included in the array then all but the last occurrence is ignored.
If this method fails, then it may do so after creating some, but not all, of the parent directories.

The following method should do what you want, just make sure you are checking the return value of mkdir() / mkdirs()
private void createUserDir(final String dirName) throws IOException {
final File homeDir = new File(System.getProperty("user.home"));
final File dir = new File(homeDir, dirName);
if (!dir.exists() && !dir.mkdirs()) {
throw new IOException("Unable to create " + dir.getAbsolutePath();
}
}

Neat and clean:
import java.io.File;
public class RevCreateDirectory {
public void revCreateDirectory() {
//To create single directory/folder
File file = new File("D:\\Directory1");
if (!file.exists()) {
if (file.mkdir()) {
System.out.println("Directory is created!");
} else {
System.out.println("Failed to create directory!");
}
}
//To create multiple directories/folders
File files = new File("D:\\Directory2\\Sub2\\Sub-Sub2");
if (!files.exists()) {
if (files.mkdirs()) {
System.out.println("Multiple directories are created!");
} else {
System.out.println("Failed to create multiple directories!");
}
}
}
}

Though this question has been answered. I would like to put something extra, i.e.
if there is a file exist with the directory name that you are trying to create than it should prompt an error. For future visitors.
public static void makeDir()
{
File directory = new File(" dirname ");
if (directory.exists() && directory.isFile())
{
System.out.println("The dir with name could not be" +
" created as it is a normal file");
}
else
{
try
{
if (!directory.exists())
{
directory.mkdir();
}
String username = System.getProperty("user.name");
String filename = " path/" + username + ".txt"; //extension if you need one
}
catch (IOException e)
{
System.out.println("prompt for error");
}
}
}

Just wanted to point out to everyone calling File.mkdir() or File.mkdirs() to be careful the File object is a directory and not a file. For example if you call mkdirs() for the path /dir1/dir2/file.txt, it will create a folder with the name file.txt which is probably not what you wanted. If you are creating a new file and also want to automatically create parent folders you can do something like this:
File file = new File(filePath);
if (file.getParentFile() != null) {
file.getParentFile().mkdirs();
}

This the way work for me do one single directory or more or them:
need to import java.io.File;
/*enter the code below to add a diectory dir1 or check if exist dir1, if does not, so create it and same with dir2 and dir3 */
File filed = new File("C:\\dir1");
if(!filed.exists()){ if(filed.mkdir()){ System.out.println("directory is created"); }} else{ System.out.println("directory exist"); }
File filel = new File("C:\\dir1\\dir2");
if(!filel.exists()){ if(filel.mkdir()){ System.out.println("directory is created"); }} else{ System.out.println("directory exist"); }
File filet = new File("C:\\dir1\\dir2\\dir3");
if(!filet.exists()){ if(filet.mkdir()){ System.out.println("directory is created"); }} else{ System.out.println("directory exist"); }

if you want to be sure its created then this:
final String path = "target/logs/";
final File logsDir = new File(path);
final boolean logsDirCreated = logsDir.mkdir();
if (!logsDirCreated) {
final boolean logsDirExists = logsDir.exists();
assertThat(logsDirExists).isTrue();
}
beacuse mkDir() returns a boolean, and findbugs will cry for it if you dont use the variable. Also its not nice...
mkDir() returns only true if mkDir() creates it.
If the dir exists, it returns false, so to verify the dir you created, only call exists() if mkDir() return false.
assertThat() will checks the result and fails if exists() returns false. ofc you can use other things to handle the uncreated directory.

This function allows you to create a directory on the user home directory.
private static void createDirectory(final String directoryName) {
final File homeDirectory = new File(System.getProperty("user.home"));
final File newDirectory = new File(homeDirectory, directoryName);
if(!newDirectory.exists()) {
boolean result = newDirectory.mkdir();
if(result) {
System.out.println("The directory is created !");
}
} else {
System.out.println("The directory already exist");
}
}

Here is one attractiveness of the java, using Short Circuit OR '||', testing of the directory's existence along with making the directory for you
public File checkAndMakeTheDirectory() {
File theDirectory = new File("/path/directory");
if (theDirectory.exists() || theDirectory.mkdirs())
System.out.println("The folder has been created or has been already there");
return theDirectory;
}
if the first part of the if is true it does not run the second part and if the first part is false it runs the second part as well

public class Test1 {
public static void main(String[] args)
{
String path = System.getProperty("user.home");
File dir=new File(path+"/new folder");
if(dir.exists()){
System.out.println("A folder with name 'new folder' is already exist in the path "+path);
}else{
dir.mkdir();
}
}
}

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