Develop Reference

Moveing files with java

I'm trying to move files using this java code and it can locate the file but not move it, just deletes the directory I'm moving it to.
public void ch() throws Exception{
if (FC.showOpenDialog(null) == JFileChooser.APPROVE_OPTION){
java.io.File file = FC.getSelectedFile();
Scanner input = new Scanner(file);
System.out.println(file);
Path source = Paths.get(file + "");
Path target = Paths.get("C:\\Users\\Marcus\\Desktop\\2");
try {
Files.move(source, target, REPLACE_EXISTING);
} catch (IOException e){
System.out.println("Failed to move the file");
}
}else{
System.out.println("?");
}
}

Add the file name at the end of your destination path, like below:
You could move files with File.ranameTo() method, like this:
file.renameTo(new File("C:\\Users\\Marcus\\Desktop\\2\\"+file.getName()));
In your example:
public void ch() throws Exception{
if (FC.showOpenDialog(null) == JFileChooser.APPROVE_OPTION){
java.io.File file = FC.getSelectedFile();
try {
file.renameTo(new File("C:\\Users\\Marcus\\Desktop\\2\\"+file.getName()));
} catch (Exception e){
System.out.println("Failed to move the file");
}
}else{
System.out.println("?");
}
}

If you want to use Files.move(), your target path should probably be the full path of the target file, not the destination directory where you want to place it.
Path target = Paths.get("C:\\Users\\Marcus\\Desktop\\2\\" + source.getName());

You should use Files.copy() instead of Files.move().

I strongly recommend the use of a third party tool such as Apache Commons IO's FileUtil class for this type of operation.
For example: FileUtil.moveFileToDirectory
Using these types of utilities saves you from many problems you aren't even aware are lurking. Yes, there are limitations to these common utils, but the benefits usually outweigh them in simple cases.
Google Guava is also an option, but I've got less experience there.

Your code is close but there a couple of potential issues. Before I start, I should say that I'm using a Mac (hence the path change), so while this is working for me, there may be some underlying permission issue on your system I can't account for.
1) You aren't using the name of the file you want to move to. You're using the directory you want to move the file to. That's a fair assumption, but you need to make it the fully qualified path and file name.
2) You are creating a Scanner to the to file but not using it. This probably doesn't really matter, but it's best to eliminate unnecessary code.
3) You don't validate the path that was created by getting the Path instance returned from Files.move().
Here is my example code. I tested it and it worked fine. Again, I'm using a Mac, so take that into account.
public void moveFile(){
JFileChooser fc = new JFileChooser("/");
if (fc.showOpenDialog(null) == JFileChooser.APPROVE_OPTION){
File file = fc.getSelectedFile();
System.out.println("Chosen File: " + file.getAbsolutePath());
String newFileName = System.getProperty("user.home")+File.separator+file.getName();
System.out.println("Attempting to move chosen file to destination: " + newFileName);
Path target = Paths.get(newFileName);
try {
Path newPath = Files.move(file.toPath(), target, REPLACE_EXISTING);
System.out.println("Path returned from move: " + newPath);
} catch (IOException e){
// Checked exceptions are evil.
throw new IllegalStateException("Unable to move the file: " + file.getAbsolutePath(),e);
}
}
}
The output from one of the tests:
Chosen File: /Users/dombroco/temp/simpleDbToFileTest1.txt
Attempting to move chosen file to destination: /Users/dombroco/simpleDbToFileTest1.txt
Path returned from move: /Users/dombroco/simpleDbToFileTest1.txt

What am i doing wrong with copying my file?

So I am trying to copy one file from one place to the other using the solution found here :
Copying files from one directory to another in Java
My code creates the new directory but cant seem to find the file ,even though the landedtitlesFile is pointing to the proper path and file. I always get my "blast" comment in case you were wondering if my program gets to the end of the method.
Thank you for your time and patience.
private File landedtitlesFile = new File("C:\\Program Files (x86)\\Steam\\SteamApps\\common\\Crusader Kings II\\common\\landed_titles\\landed_titles.txt");
private String modPath = "C:\\Users\\Bernard\\Documents\\Paradox Interactive\\Crusader Kings II\\mod\\viking";
public void createCopyLandedTitles(Boolean vanilla){
if (vanilla == true) {
File dir = new File(modPath + "\\common\\landed_titles");
dir.mkdir();
try{
FileUtils.copyFile(landedtitlesFile,dir);
}
catch (IOException e ){
System.out.println("blast");
}
}

copyFile expects the second parameter to be the destination file, not a destination directory. You need to give it the target name of the file within that directory:
FileUtils.copyFile(
landedtitlesFile,
new File(dir, landedtitlesFile.getName());
Exception objects generally contain some information on the cause. If you print out the exception with e.printStackTrace(); (or rethrow it up the stack with throw new RuntimeException(e);) then you will be able to see what it says.

File.createNewFile() failing in java (Ubuntu 12.04)

I am trying to createNewFile() in java.I have written down the following example.I have compiled it but am getting a run time error.
import java.io.File;
import java.io.IOException;
public class CreateFileExample
{
public static void main(String [] args)
{
try
{
File file = new File("home/karthik/newfile.txt");
if(file.createNewFile())
{
System.out.println("created new fle");
}else
{
System.out.println("could not create a new file");
}
}catch(IOException e )
{
e.printStackTrace();
}
}
}
It is compiling OK.The run time error that I am getting is
java.io.IOException: No such file or directory
at java.io.UnixFileSystem.createFileExclusively(Native Method)
at java.io.File.createNewFile(File.java:947)
at CreateFileExample.main(CreateFileExample.java:16)

some points here
1- as Victor said you are missing the leading slash
2- if your file is created, then every time you invoke this method "File.createNewFile()" will return false
3- your class is very platform dependent (one of the main reasons why Java is powerful programming language is that it is a NON-PLATFORM dependent), instead you can detect a relative location throw using the System.getProperties() :
// get System properties :
java.util.Properties properties = System.getProperties();
// to print all the keys in the properties map <for testing>
properties.list(System.out);
// get Operating System home directory
String home = properties.get("user.home").toString();
// get Operating System separator
String separator = properties.get("file.separator").toString();
// your directory name
String directoryName = "karthik";
// your file name
String fileName = "newfile.txt";
// create your directory Object (wont harm if it is already there ...
// just an additional object on the heap that will cost you some bytes
File dir = new File(home+separator+directoryName);
// create a new directory, will do nothing if directory exists
dir.mkdir();
// create your file Object
File file = new File(dir,fileName);
// the rest of your code
try {
if (file.createNewFile()) {
System.out.println("created new fle");
} else {
System.out.println("could not create a new file");
}
} catch (IOException e) {
e.printStackTrace();
}
this way you will create your file in any home directory on any platform, this worked for my windows operating system, and is expected to work for your Linux or Ubuntu as well

You're missing the leading slash in the file path.
Try this:
File file = new File("/home/karthik/newfile.txt");
That should work!

Actually this error comes when there is no directory "karthik" as in above example and createNewFile() is only to create file not for directory use mkdir() for directory and then createNewFile() for file.

How do I detemine the max path length allowed when creating a file in Java

How do I detemine the max path length allowed when creating a file in Java.
I'm using Java 7 so can make use of Java NIO2 if that helps but how can I detemine the max length allowed on the filesystem for a file and ensure I do not try and create a file that has such an invalid path.
I want to shorten the path (substring) before I try and create it not deal with a problem afterwards especially because the exception/error message could vary from fileystem to filesystem.
I don't want to hard code length per platform, that wouldnot work anyway as a Windows application could access an OSX filessystem ectera.
It only fails when an attempt is made to create file
i.e
try
{
Path p = Paths.get("C:/User/Mesh/kkkkkkkkkkkkkkkkkkkkkkkkkkrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkk.txt");
Files.createFile(p);
}
catch(Exception e)
{
e.printStackTrace();
}
gives
java.nio.file.FileSystemException: C:\User\Mesh\kkkkkkkkkkkkkkkkkkkkkkkkkkrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkk.txt: The filename, directory name, or volume label syntax is incorrect.
at sun.nio.fs.WindowsException.translateToIOException(WindowsException.java:86)
at sun.nio.fs.WindowsException.rethrowAsIOException(WindowsException.java:97)
at sun.nio.fs.WindowsException.rethrowAsIOException(WindowsException.java:102)
at sun.nio.fs.WindowsFileSystemProvider.newByteChannel(WindowsFileSystemProvider.java:229)
at java.nio.file.Files.newByteChannel(Files.java:315)
at java.nio.file.Files.createFile(Files.java:586)
Compare to Java 6 method
try
{
//File file = new File("C:/User/Mesh/kkkkkkkkkkkkkkkkkkkkkkkkkkrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkk.txt");
Path p = Paths.get("C:/User/Mesh/kkkkkkkkkkkkkkkkkkkkkkkkkkrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkk.txt");
p.toFile().createNewFile();
//boolean result=file.isFile();
//System.out.println("Result is:"+result);
}
catch(Exception e)
{
e.printStackTrace();
}
gives totally different error
java.io.IOException: The filename, directory name, or volume label syntax is incorrect
at java.io.WinNTFileSystem.createFileExclusively(Native Method)
at java.io.File.createNewFile(File.java:947)
but irrelvant really because I want to do something before file is created
EDIT:
Looks like 255 characters is a good default http://en.wikipedia.org/wiki/Filename anyway

There is a method getPath in java.nio.file.FileSystem that can be used to create a valid path name, or else it throws an InvalidPathException. Maybe that could help you.

Try something along these lines:
boolean success = true;
File testFile = new File("/a/really/long/name");
try {
success = testFile.createNewFile();
} catch (IOException ioe) {
// anyway check the exception, the problem could have been other
// for example: duplicate name, lack of permissions, etc.
success = false;
}
if (!success) {
// error creating file
}

Java's createNewFile() - will it also create directories?

I've got a conditional to check if a certain file exists before proceeding (./logs/error.log). If it isn't found I want to create it. However, will
File tmp = new File("logs/error.log");
tmp.createNewFile();
also create logs/ if it doesn't exist?

No.
Use tmp.getParentFile().mkdirs() before you create the file.

File theDir = new File(DirectoryPath);
if (!theDir.exists()) theDir.mkdirs();

File directory = new File(tmp.getParentFile().getAbsolutePath());
directory.mkdirs();
If the directories already exist, nothing will happen, so you don't need any checks.

Java 8 Style
Path path = Paths.get("logs/error.log");
Files.createDirectories(path.getParent());
To write on file
Files.write(path, "Log log".getBytes());
To read
System.out.println(Files.readAllLines(path));
Full example
public class CreateFolderAndWrite {
public static void main(String[] args) {
try {
Path path = Paths.get("logs/error.log");
Files.createDirectories(path.getParent());
Files.write(path, "Log log".getBytes());
System.out.println(Files.readAllLines(path));
} catch (IOException e) {
e.printStackTrace();
}
}
}

StringUtils.touch(/path/filename.ext) will now (>=1.3) also create the directory and file if they don't exist.

No, and if logs does not exist you'll receive java.io.IOException: No such file or directory
Fun fact for android devs: calls the likes of Files.createDirectories() and Paths.get() would work when supporting min api 26.