import java.io.File;
class AttriDemo{
public static void main(String args[]){
File f1 = new File("FileIO/file.txt");
System.out.println("File name : " + f1.getName());
System.out.println("File path : " + f1.getPath());
System.out.println("File AbsPath : " + f1.getAbsolutePath());
System.out.println("File parent : " + f1.getParent());
f1.setWritable(true);
if(f1.canWrite())
{
System.out.println("File is Writeable");
}
else
{
System.out.println("File is not Writeable");
}
if(f1.canRead())
{
System.out.println("Is readable");
}
else
{
System.out.println("File is not readable");
}
}
}
I the file is readable and writable in real...
then I tried setting it to Writable explicitly but still the output shows it as the file is not writable!!
output:
....
The file is not writable.
The file is not readable.
File f1 = new File("D:/javaProgs/FileIO/AttriDemo.java");
doing this helps solve the problem.
but can someone explain how? I mean the file was in the same directory and the statements above were running just fine. e.g getName() getParent()
What's fooling you is you can create a File object regardless of the path you specified exists or not and you can call all those getParent, getPath functions on that object.
You can create a File object that's not backed by a real file for various reasons like to check if it exists or to create a file specified by that objects path and name.
You can use File.exists() to see if file really exists on file system.
Related
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();
}
}
}
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();
}
}
}
I'm trying to create an empty .properties file on my filesystem using java.io.File.
My code is:
File newFile = new File(new File(".").getAbsolutePath() + "folder\\" + newFileName.getText() + ".properties");
if (newFile.createNewFile()){
//do sth...
}
It says that it's impossible to find the specified path.
Printing the Files's constructor's argument it shows correctly the absolute path.
What's wrong?
You can use new File("folder", newFileName.getText() + ".properties") which will create a file reference to the specified file in the folder directory relative to the current working directory
You should make sure that the directory exists before calling createNewFile, as it won't do this for you
For example...
File newFile = new File("folder", newFileName.getText() + ".properties");
File parentFile = newFile.getParentFile();
if (parentFile.exists() || parentFile.mkdirs()) {
if (!newFile.exists()) {
if (newFile.createNewFile()){
//do sth...
} else {
throw new IOException("Could not create " + newFile + ", you may not have write permissions or the file is opened by another process");
}
}
} else {
throw new IOException("Could not create directory " + parentFile + ", you may not have write permissions");
}
I think the "." operator might be causing the error not sure what you are trying to do there, may have misunderstood your intentions but try this instead:
File newFile = new File(new File("folder\\").getAbsolutePath() + ".properties");
Trivially I missed that new File(".").getAbsolutePath() returns the project's absolute path with the . at the end so my folder whould be called as .folder. Next time I'll check twice.
I have written a short program that will find a file I have made and print some of its details. It executes all right, but it cannot detect the file size or if it is hidden or not. E.G.
file path: C:\temp\filetext.txt last modified: 0 file size: 0 Is file hidden?false
The file does exist in the temp folder on C. I'm not really sure what the problem is
public void Q1()
{
String fileName = "filetext.txt";
getFileDetails(fileName);
}
public void getFileDetails(String fileName)
{
String dirName = "C:/temp/";
File productsFile = new File(dirName + fileName);
long size = productsFile.length();
System.out.println("file path: " + productsFile.getAbsolutePath() + " last modified: " + productsFile.lastModified() + " file size: " + productsFile.length() + " Is file hidden?" + productsFile.isHidden());
}
File does not need a physical file to work with. Therefore your File object can exist even if the physical file it is supposed to represent does not exist/cannot be found. Check the JavaDoc for length() and lastModified(), they both return 0L in case for example the file does not exist. So make sure your File objects is linked to an existing file on your file system by calling file.exists() before calling the other methods.
I was just wondering if the code I made will work to create multiple directories within each other. I used this as a reference.
String username = enterUserTF.getText(); //the username the user enters in a textfield.
boolean myGamesFolderSuccess = new File(System.getProperty("user.home"), "My Games").mkdir();
boolean mainFolderSuccess = new File("My Games", "Type King").mkdir();
boolean userSuccess = new File("TypeKing", username).mkdir(); //creates a folder with the users username.
if(myGamesFolderSuccess){
if(mainFolderSuccess){
if(userSuccess){
System.out.println("Directory " + username + " created.");
File f = new File(username + "/test.txt");
if(!f.exists()){
try {
f.createNewFile();
} catch (IOException e) {
e.printStackTrace();
System.out.println("Could not create user's file.");
}
}
}
}
}
}
So to sum up the above, I made the the first directory "My Games" in user.home, then placed my game's name, "Type King" in that directory, and whenever the user enters a username, I want a directory to be created that is their username. File f just checks for a file in the username directory.
It is recommended to use the mkdirs method of the File class instead of checking multiple status flags when creating nested directories. Also, never use concatenation for creating File objects/paths.
Also, if you want your game to be portable, make sure you don't have special characters in your directory names like a space etc.Why are you asking user for the name instead of retrieving it from user.name system property? Something like this should work:
String username = System.getProperty("user.name");
File myGamesDir = new File(System.getProperty("user.home"), "my-games");
File typeKingDir = new File(myGamesDir, "type-king");
File userDir = new File(typeKingDir, username);
boolean userSuccess = userDir.mkdirs();
if(userSuccess){
System.out.println("Directory " + username + " created.");
File f = new File(userDir, "test.txt");
if(!f.exists()){
try {
f.createNewFile();
} catch (IOException e) {
e.printStackTrace();
System.out.println("Could not create user's file.");
}
}
}
If you pass a full path to File.mkdirs (with an s) it will make an arbitrarily deep directory structure. You don't have to build paths one directory at a time. If the directories already exist, or if some of them exist, it will still work as you expect.
import java.io.File;
import javax.swing.JOptionPane;
class Dirs {
public static void main(String[] args) throws Exception {
String subDir = "My Games|Type King";
String userName = JOptionPane.showInputDialog(
null,
"Who are you?");
subDir += "|" + userName;
String[] parts = subDir.split("\\|");
File f = new File(System.getProperty("user.home"));
for (String part : parts) {
f = new File(f, part);
}
boolean madeDir = f.mkdirs();
System.out.println("Created new dir: \t" + madeDir + " \t" + f);
f = new File(f, "eg.txt");
if (!f.exists()) {
boolean madeFile = f.createNewFile();
System.out.println(
"Created new file: \t" + madeFile + " \t" + f );
}
}
}
Output
Created new dir: true C:\Users\Andrew\My Games\Type King\BilboBaggins
Created new file: true C:\Users\Andrew\My Games\Type King\BilboBaggins\eg.txt
I think its better to use existing functionality available in the API. If you don't have any restrictions consider switching to the latest JDK. In 1.7 Oracle did introduce so many enhancements including IO and New IO.
For creating multiple directories within each other you can take advantage of Files.createDirectories available since 1.7. "It will create a directory by creating all nonexistent parent directories first."