Getting pop up after opening excel file created through Java

[Swapnil Sanghai]

Hi i used below code to create file,

public class Example {

	public static void main(String[] args){ 
		
		File newFile = new File("D:\\Test.xls");
		FileOutputStream fos = null;
		
		if (!newFile.exists()){
			try {
				newFile.createNewFile();
			} catch (IOException e1) {
				// TODO Auto-generated catch block
				e1.printStackTrace();
			}
		}else{
			newFile.delete();
		}
		
		try {
			fos = new FileOutputStream(newFile);
		} catch (FileNotFoundException e) {
			// TODO Auto-generated catch block
			e.printStackTrace();
		}
		
		try {
			fos.close();
		} catch (IOException e) {
			// TODO Auto-generated catch block
			e.printStackTrace();
		}
	}

}

File is getting created successfully, but when i open it manually just to see i am getting pop saying "the file format and extension of 'Test.xls' does not match".

Please refer attached image.

[Carey Brown]

Yes, you've created a file but just because the file name ends with ".xls" does not mean it's an Excel file.

If you really want to read/write an Excel file the best way to do it is with the Apache POI library. It is not a particularly simple library though and would probably present difficulties to a Java beginner.

Another way to approach the problem is by writing out a CSV (comma separated variable) file which is a basic text file separating columns of data with commas. Excel can read and write CSV files. You won't need a library for this.

[Swapnil Sanghai]

I understood it, but here i want to use POI only.
Can you please tell me how can i resolve it.
I am trying to get answers from different sites but its not working.

Thanks.

[Paul Clapham]

So far you have only created an empty file. But... Carey recommended you could use POI, and you said you wanted to use POI. So it looks like that's settled then. I don't see what's left to be resolved. Go ahead and use POI to write the data into your Excel file.

Of course if you run into problems, the Ranch is here to help.

[Tim Moores]

Swapnil Sanghai wrote:I am trying to get answers from different sites but its not working.

Tells us what you did, and what exactly "it's not working" means. Post the code you have so far, and how it is and how it isn't working according to your expectations.

[Knute Snortum]

Here are some examples for how to write an Excel file with POI.  Tell us what problems you run into.