Export array values to csv file java

Question

I just need help exporting array elements to a csv file. I don't know what's wrong with my code. Any help is gladly appreciated. Thanks.

for (int index = 0; index < cols.length; index++)
{
    FileWriter fw = new FileWriter(newFileName);
    if (index == cols.length - 1)
    {
        fw.append(cols[index]);
    }
    else
    {
        fw.append(cols[index]);
        fw.append(",");
    }

}

When I run this. Nothing happens to my csv file. Infact, it wipes everything of. Please help.

Answer 1

Assuming you're storing String in your array, I post an alternative solution:

BufferedWriter br = new BufferedWriter(new FileWriter("myfile.csv"));
StringBuilder sb = new StringBuilder();

// Append strings from array
for (String element : array) {
 sb.append(element);
 sb.append(",");
}

br.write(sb.toString());
br.close();

Best regards.

Answer 2

you need to flush the written data, close your FileWriter.

      finally {
        fw.close(); // close will automatically flush the data 
      }

Also, use BufferedWriter or PrintWriter instead as they are highly efficient and evolved than FileWriter.

Btw, declare the FileWriter outta your for loop. Currently it will overwrite the column for each iteration.