Question

I have a csv file in which I am able to insert the header for the first run, but when I again write the file the program is creating the header again. Is there a way to check if csv file has a header and if yes then to skip it?

Answer 1

You would have to read the first line and test if the first column matches the column header you expect. Since your code inserts the header, I’m assuming it knows what the header should look like. You can use this same variable in your header check. Something like:

String HEADER = "column1,column2,column3";
String COLUMN1 = HEADER.substring(0,HEADER.indexOf(",")+1); //Or just set it to "column1", but that would be violating the DRY principle!

//...Get line1, column1 from the file you are reading

if(!line1Column1.equals(COLUMN1))
{
    out.write(HEADER); 
}

// Print rows of data...