Java - Writing strings to a CSV file

50

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

This question is tagged with java excel csv export-to-csv

~ Asked on 2015-05-06 10:22:16

The Best Answer is


103

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

When you put ID as the first character in a Spreadsheet type file, it matches the specification of a SYLK file and MS Excel (and potentially other Spreadsheet Apps) try to open it as a SYLK file. But at the same time, 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.

To solve the issue, change "ID" to "id" and it should work as expected.

enter image description here

This is weird. But, yeah!

Also trying to minimize file access by using file object less.

I tested and the code below works perfect.

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(new File("test.csv"))) {

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

      sb.append("1");
      sb.append(',');
      sb.append("Prashant Ghimire");
      sb.append('\n');

      writer.write(sb.toString());

      System.out.println("done!");

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

  }
}

~ Answered on 2015-05-06 10:35:00


12

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

public class CsvFile {

    public static void main(String[]args){
        PrintWriter pw = null;
        try {
            pw = new PrintWriter(new File("NewData.csv"));
        } catch (FileNotFoundException e) {
            e.printStackTrace();
        }
        StringBuilder builder = new StringBuilder();
        String columnNamesList = "Id,Name";
        // No need give the headers Like: id, Name on builder.append
        builder.append(columnNamesList +"\n");
        builder.append("1"+",");
        builder.append("Chola");
        builder.append('\n');
        pw.write(builder.toString());
        pw.close();
        System.out.println("done!");
    }
}

~ Answered on 2016-05-25 15:21:25


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