I want to create a folder in ex. my desktop in Mac OS X
I try to use this code, instead of Mymac is my name of course:)
String path="/Users/Mymac/Desktop";
String house = "My_home";
File file=new File(path);
if(!file.exists())
file.mkdirs(); // or file.mkdir()
file=new File(path + "/" + house);
try {
if(file.createNewFile())
{
}
} catch (IOException ex) {
ex.printStackTrace();
}
Do you know how I could create a new folder?
And another thing is when I want to create a folder in the directory where my code is, do you know how I could write that? I have tried
String path="./";
String path="::MyVolume";
String path=".";
A platform-independent way:
File rootDir = File.listRoots()[0];
File dir = new File(new File(new File(rootDir, "Users"), "Mymac"), "Desktop");
if (!dir.exists()){
dir.mkdirs();
}
Your code is ok and will work. Perhaps you have a typo in your username in your file-path ("Mymac"), so you don't see the changes, since they go to another folder.
Running this code on my machine works fine and gives the expected result.
To make your code platform-independant, you can build your file-path with the following trick:
File path = new File(File.listRoots()[0], "Users" + System.getProperty("file.separator") + "Mymac" + System.getProperty("file.separator") + "Desktop"));
If "My_home" should be a folder and not a file, you have to change the file.createNewFile() - command. More detailed information you'll find in the answer of Thomas.
To find the folder/directory where one of your classes is (assuming they are not in a Jar), and then to create a subfolder there:
String resource = MyClass.class.getName().replace(".", File.separator) + ".class";
URL fileURL = ClassLoader.getSystemClassLoader().getResource(resource);
String path = new File(fileURL.toURI()).getParent();
String mySubFolder = "subFolder";
File newDir = new File(path + File.separator + mySubFolder);
boolean success = newDir.mkdir();
(The code above could be made more compact, I listed it more verbosely to demonstrate all the steps.) Of course, you need to be concerned about permission issues. Make sure that the user which is running java has permission to create a new folder.
Use file.mkdir() or file.mkdirs() instead of file.createNewFile() and it should work, if you have permission to create new folders and files.
mkdirs() will create the subfolders if they don't exist, mkdir() won't.
To create a directory in your base directory (the one you start your application from), just provide a relative path name: new File("mydir").mkdir();
Edit: to make file handling easier, I'd suggest you also have a look at Apache Commons' FilenameUtils and FileUtils.
Related
i upload a csv file from client side and i want to create this file in server side.
Here is my function
public void uploadFile(FileUploadEvent e) throws IOException{
UploadedFile uploadedCsv=e.getFile();
String filePath="//ipAdress:/home/cg/Temp/input/ressource.csv";
byte[] bytes=null;
if(uploadedCsv != null){
bytes=uploadedCsv.getContents();
BufferedOutputStream stream = new BufferedOutputStream(new FileOutputStream(new File(filePath)));
String filename = FilenameUtils.getName(uploadedCsv.getFileName());
stream.write(bytes);
stream.close();
}
}
When I want to write the file I get this exception (No such file or directory)
SEVERE: java.io.FileNotFoundException: /ipAdress:/home/cg/Temp/input/ressource.csv (No such file or directory)
Knowing that the / home / cg / Temp / input path is created on the server.
Could you try:
String filePath="////ipAdress/home/cg/Temp/input/ressource.csv";
Instead of:
String filePath="//ipAdress:/home/cg/Temp/input/ressource.csv";
And this:
new File(new URI(filePath))
Instead of:
new File(filePath)
Or you can use jcif API How can I open a UNC path from Linux in Java?
I would use the <file>.mkdirs(); at one level above the file itself.
So do String filePath="//ipAdress:/home/cg/Temp/input
File directory = new File(filePath);
directory.mkdirs();
You can then make the file
File tempFile = new File(directory + "/ressource.csv);
Or a cleaner solution all around is just use Files.createTempFile(prefix, suffix) this will create a file in the temp directory of the system.
The reason that your code does not work is that you are trying to use a UNC pathname on Linux. Linux does not support UNC pathnames ... natively. They are a Windows-ism.
Here's your example
"//ipAdress:/home/cg/Temp/input/ressource.csv";
If you try to use that on Linux, the OS will look for a directory in the root directory of the file system. The directory it will look for will have the name ipaddress: ... noting that there is a colon in the directory name!
That will most likely fail ... because no directory with that name exists in the / directory.. And the exception message you are getting is consistent with this diagnosis.
If you are doing this because you are trying to push files out to other systems then you are going to do it some other way. For example:
Use NFS and mount the other system's file systems on the server.
Use a Java implementation of UNC names; e.g. How can I open a UNC path from Linux in Java?
(Which ever way you do it, there are security issues to consider!)
trying this new File(new URI(filePath)) instead of new File(filePath) i get this erreur. SEVERE: java.lang.IllegalArgumentException: URI is not absolute
It won't work. A UNC name is NOT a valid URL or URI.
I have found a solution for this problem, but it's not smart and still and it works
String fileName="ressource.csv";
File f = new File(System.getProperty("user.home") + "/Temp/input",fileName);
if (f.exists() && !f.canWrite())
throw new IOException("erreur " + f.getAbsolutePath());
if (!f.exists())
Files.createFile(f.toPath());
if (!f.isFile()) {
f.createNewFile(); // Exception here
} else {
f.setLastModified(System.currentTimeMillis());
}
Pending a more intelligent solution
I have my java code like below-
string folderName = "d:\my folder path\ActualFolderName";
File folder = new File( folderName );
folder.mkdirs();
So here as given directory path has space in it. folder created is d:\my, not the one I am expecting.
Is there any special way to handle space in file/folder paths.
You should us \\ for path in java. Try this code
String folderName = "D:\\my folder path\\ActualFolderName";
File folder = new File( folderName );
folder.mkdirs();
Or use front-slashes / so your application will be OS independent.
String folderName = "D:/my folder path1/ActualFolderName";
Unless you are running a really old version of Java, use the Path API from JDK7:
Path p = Paths.get("d:", "my folder path", "ActualFolderName");
File f = p.toFile();
It will take care of file separators and spaces for you automatically, regardless of OS.
Following alternatives should work in Windows:
String folderName = "d:\\my\\ folder\\ path\\ActualFolderName";
String folderName = "\"d:\\my folder path\\ActualFolderName\"";
You need to escape your path (use \\ in your path instead of \) and you also need to use String, with an uppercase S, as the code you posted does not compile. Try this instead, which should work:
String folderName = "D:\\my folder path\\ActualFolderName";
new File(folderName).mkdirs();
If you are getting your folder name from user input (ie.not hardcoded in your code), you don't need to escape, but you should ensure that it is really what you expect it is (print it out in your code before creating the File to verify).
If your are still having problems, you might want to try using the system file separator character, which you can get with System.getProperty(file.separator) or accesing the equivalent field in the File class. Also check this question.
You need to escape path seprator:
String folderName = "D:\\my folder path\\ActualFolderName";
File file = new File(folderName);
if (!file.exists()) {
file.mkdirs();
}
First of all, the String path you have is incorrect anyway as the backslash must be escaped with another backslash, otherwise \m is interpreted as a special character.
How about using a file URI?
String folderName = "d:\\my folder path\\ActualFolderName";
URI folderUri = new URI("file:///" + folderName.replaceAll(" ", "%20"));
File folder = new File(folderUri);
folder.mkdirs();
I'm making a game that saves information into a binary file so that I can start at the point I left the game on the next use.
My problem is that it works fine on my PC because I chose a path that already existed to save the file, but once I run the game on another PC, I got an error saying the path of the file is invalid (because i doesn't exist yet, obviously).
Basically I'm using the File class to create the file and then the ObjectOutputStream and ObjectInputStream to read/write info.
Sorry for the noob question, I'm still pretty new to using files.
You must first check if the directory exists and if it does not exist then you must create it.
String folderPath = System.getProperty("user.home") + System.getProperty("file.separator") + "MyFolder";
File folder = new File(folderPath);
if(!folder.exists())
{
folder.mkdirs();
}
File saveFile = new File(folderPath, "fileName.ext");
Please note that the mkdirs() method is more useful in this case instead of the mkdir() method as it will create all non existing parent folders.
Hope this helps. Good luck and have fun programming!
Cheers,
Lofty
You are looking for File mkdirs()
Which will create all the directories necessary that are named in your path.
For example:
File dirs= new File("/this/path/does/not/exist/yet");
dirs.mkdir();
File file = new File(dirs, "myFile.txt");
Take in consideration that it may fail, due to proper file permissions.
My solution has been create a subdirectory within the user's home directory (System.getProperty("user.home")), like
File f = new File(System.getProperty("user.home") + "/CtrlAltDelData");
f.mkdir();
File mySaveFile = new File (f, "save1.txt");
After reading that is it possible to create a relative filepath name using "../" I tried it out.
I have a relative path for a file set like this:
String dir = ".." + File.separator + "web" + File.separator + "main";
But when I try setting the file with the code below, I get a FileNotFoundException.
File nFile= new File(dir + File.separator + "new.txt");
Why is this?
nFile prints: "C:\dev\app\build\..\web\main"
and
("") file prints "C:\dev\app\build"
According to your outputs, after you enter build you go up 1 time with .. back to app and expect web to be there (in the same level as build). Make sure that the directory C:\dev\app\web\main exists.
You could use exists() to check whether the directory dir exist, if not create it using mkdirs()
Sample code:
File parent = new File(dir);
if(! parent.exists()) {
parents.mkdirs();
}
File nFile = new File(parent, "new.txt");
Note that it is possible that the file denoted by parent may already exist but is not a directory, in witch case it would not be possible to use it a s parent. The above code does not handle this case.
Why wont you take the Env-Varable "user.dir"?
It returns you the path, in which the application was started from.
System.getProperty(user.dir)+File.separator+"main"+File.separator+[and so on]
I am creating files with Java in Windows. This works:
String newFile = "c:/"+Utilities.timeFormat();
...
some code that creates a folder
This does not work:
String newFile = "c:/newDirectory/"+Utilities.timeFormat();
...
some code that creates a folder
You have to use File.mkdir() or File.mkdirs() method to create a folder.
EDIT:
String path="c:/newDirectory";
File file=new File(path);
if(!file.exists())
file.mkdirs(); // or file.mkdir()
file=new File(path + "/" + Utilities.timeFormat());
if(file.createNewFile())
{
}
without knowing your actual code which is creating the directory:
use mkdirs() instead of mkdir()
Can you check that you have permissions to create a folder in c:/?
Can you show us the stacktrace too?
If "newDirectory" doesn't exist yet, you should use the method mkdirs() from the File class to create all the directories in between.
The fact that the directory doesn't exist is probably why it isn't working he first time through. As many have pointed out use mkdirs() will ensure if the file you want to write is in subfolders it will create them. Now here is what it might look like:
File file = new File( new File("c:/newDirectory"), Utilities.timeFormat() );
if( !file.getParentFile().exists() ) {
file.getParentFile().mkdirs();
}
OutputStream stream = new BufferedOutputStream( new FileOutputStream( file ) );
try {
// put your code here to write the file
} finally {
stream.close();
}
Notice I'm not using + to create a path. Instead I create a File object, and pass it the parent File and the name of the file. Also notice I'm not putting path separators in between the parent and filename. Using the File constructor takes care of a system independent way of creating paths.