File I/O

[Puja Sinha]

Hi,

Can we replace the following piece of code with the one listed below it?

try {
File file = new File("fileWrite2.txt");
FileWriter fw = new FileWriter(file); // create an actual file & a FileWriter obj
fw.write("howdy\nfolks\n"); // write characters to the file
fw.flush(); // flush before closing
fw.close(); // close file when done
} catch(IOException e) { }

Replace with

try {
File file = new File("fileWrite2.txt");
file.createNewFile();
FileWriter fw = new FileWriter(file);
fw.write("howdy\nfolks\n");
fw.flush(); // flush before closing
fw.close(); // close file when done
} catch(IOException e) { }

[Robin John]

why not ?

but it seems unnecessary, FileWriter does create a new file before writing to it (windows).. and if any file exists the FileWriter overwrites it. but file.createFile() doesn't create a new file if the file already exists.


Note: from javadocs

Whether or not a file is available or may be created depends upon the
* underlying platform. Some platforms, in particular, allow a file to be
* opened for writing by only one FileWriter (or other file-writing
* object) at a time. In such situations the constructors in this class
* will fail if the file involved is already open.

[Puja Sinha]

Hi Robin,

Thanks for your response.
But as per the javadoc you have attached :

Robin John wrote: Some platforms, in particular, allow a file to be opened for writing by only one FileWriter (or other file-writing object) at a time. In such situations the constructors in this class will fail if the file involved is already open.

Does it mean that if there are two threads trying to work on the same file and one thread already has the file opened up then the other thread will fail to get an instance of the writer object ?

but if one thread has written to and closed the file, then the other thread will overwrite that file and open it ?

[Robin John]

Puja Sinha wrote:Hi Robin,

Thanks for your response.
But as per the javadoc you have attached :

Robin John wrote: Some platforms, in particular, allow a file to be opened for writing by only one FileWriter (or other file-writing object) at a time. In such situations the constructors in this class will fail if the file involved is already open.

Does it mean that if there are two threads trying to work on the same file and one thread already has the file opened up then the other thread will fail to get an instance of the writer object ?

... will fail to write to the file... and why dont you try ?

Note: you should not use it as a file lock mechanism.