CSV file with "ID" as first item is corrupt in Excel

Question

I am trying to write data to a csv file with java, however when I try opening the produced file with excel I am getting an error saying the file is corrupt. Upon opening the file in notepad it looks to be formatted correctly so I'm not sure what the issue is. I am using the FileWriter class to output the data to the file.

FileWriter writer = new FileWriter("test.csv");

writer.append("ID");
writer.append(',');
writer.append("name");
writer.append(',');
...
writer.append('\n');

writer.flush();
writer.close();

Do I need to use some library in java in order to print to a csv file? I presumed you could just do this natively in java as long as you used the correct formatting.

Appreciate the help,

Shaw

Answer 1

It's because MS Excel can't decide how to open the file with such content.

To solve the issue, replace "ID" with "id".

When you have ID as the first word in a SpreadSheet type file, it matches the specification of a SYLK file and MS Excel (and potentially other SpreadSheet Apps) attempts to open as a SYLK file. However, it does not meet the complete specification of a SYLK file since rest of the values in the file are comma separated. Hence, the error is shown.

id	Name
1	Jon Doe
2	Jane Doe

As a bonus, trying to minimize file access by using file object less.

I tested and the code below should work.

import java.io.File;
import java.io.FileNotFoundException;
import java.io.PrintWriter;

public class CsvWriter {
  public static void main(String[] args) {

    try (PrintWriter writer = new PrintWriter("test.csv")) {

      StringBuilder sb = new StringBuilder();
      sb.append("id");
      sb.append(',');
      sb.append("Name");
      sb.append('\n');

      sb.append("1");
      sb.append(',');
      sb.append("Jon Doe");
      sb.append('\n');

      sb.append("2");
      sb.append(',');
      sb.append("Jane Doe");
      sb.append('\n');

      writer.write(sb.toString());

      System.out.println("write success.");

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

  }
}