Creating file using try and catch

[Nelson Sam]

I want to create a new file using try checking if the file already exists and then if it exists if should be handled by catch.
I am able to create a new file when I simply give new File(f).createNewFile(); but when I give a directory
new File(f,"C:\\temp").createNewFile(); It throws system cannot find path specified.
Also I dont know how to check if a file already exists

 
import java.io.*;
class filez

{

public static void main(String args[])
	{
	String f="ifile.txt";

		try
		{
		new File(f,"C:\\temp").createNewFile(); 
		}
		
		catch(IOException e)
		{
		System.out.println(e);
		}
	}
	
}
	  

[Prasad Krishnegowda]

new File(f,"C:\\temp").createNewFile();

In the above part of code, the first argumet should be path and the second argument should be the file name. you have interchanged that. change the above to

 new File("C:\\temp",f).createNewFile();         

...

[Joanne Neal]

You've got your parameters the wrong way round.

new File(f,"C:\\temp").createNewFile();

is trying to create a file called c:\temp in a directory called ifile.txt.

As for checking if a file exists, the File class has a very suitably named method. Check the Javadoc.

[kunu patil]

Hi

You may do it as follows-

   import java.io.*;  

 class filez {  
    public static void main(String args[]){  
		String f="ifile.txt";  
		 
		 
        File fileInstance =  new File("C:\\temp",f);   
        
		try{
			if(!fileInstance.createNewFile())
				throw new IOException("Specified File already exists!");
		 }
         catch(IOException e) {  
			System.out.println(e);  
         }  
     }    
 } 

Hope this clarifies.

[Peter Taucher]

Nelson Sam wrote:Also I dont know how to check if a file already exists

The API docs are your friend. Why not use exists() method of File class?
-> http://java.sun.com/javase/6/docs/api/java/io/File.html#exists()

[Nelson Sam]

Appreciate everyone for helping

@kunu patil-Can you explain more about fileInstance.I could not find in javadocs.Thanks for adding the required codes

@Peter Taucher-Thanks for link.I tired using exists method.

 
boolean b=f.exists();
if(b==true)
.....

Isn't above code correct.When I compile i get this error

filez.java:11: cannot find symbol
symbol : method exists()
location: class java.lang.String
boolean b=f.exists();
^

[Joanne Neal]

f is a String.
exists() is a method of the File class.

And don't use if (b == true), just use if (b). It avoids possible problems with mixing up = and ==.

[kunu patil]

Nelson Sam wrote:Appreciate everyone for helping

@kunu patil-Can you explain more about fileInstance.I could not find in javadocs.Thanks for adding the required codes

@Peter Taucher-Thanks for link.I tired using exists method.

 
boolean b=f.exists();
if(b==true)
.....

Isn't above code correct.When I compile i get this error

filez.java:11: cannot find symbol
symbol : method exists()
location: class java.lang.String
boolean b=f.exists();
^

Hi,

fileInstance is an reference variable that holds reference to a File object. If you want to see JavaDoc for this you should search for "File" and not for "fileInstance".

[Nelson Sam]

Thanks for the interest friends.
My problems are solve now
See you very soon with another one

[Peter Taucher]

It would only be polite to let the other people here around know 'how' you solved your problem. It even might help further help seeking persons sometime.

[Nelson Sam]

Thanks for suggestion Peter Taucher.

Here is how I solved the problem.

OLD ONE

   
import java.io.*;
class filez

{

public static void main(String args[])
	{
	String f="ifile.txt";

		try
		{
		new File(f,"C:\\temp").createNewFile(); 
		}
		
		catch(IOException e)
		{
		System.out.println(e);
		}
	}
	
}
	    

NEW ONE

  {

public static void main(String args[])
	{
	File f;
	f=new File("nel.txt");
	Boolean check=f.exists();
	
		try
		{
		if(!check)
		{
		f.createNewFile();
		System.out.println("File Created"); 
		}
		else
		{
		throw new IOException("Specified File already exists!");
		}
		}

		catch(IOException e)
		{
		System.out.println(e.getMessage());
		} 
	}
	
}
	  

Earlier I had assigned the file name to string f.and checked using exists() method of file class,Since f is a string and doesnt belong to a file class f.exists() didnt work.

So I corrected it to
File f;
f=new File("nel.txt");
Boolean check=f.exists();

[Joanne Neal]

If you look at the API docs for the File.createNewFile() method, you will find that this code could be simplified.