如何写一个以-开头的字符串到csv文件中？

Question

I am trying to write data to CSV file.

The string value which starts with - is getting converted to #NAME? automatically when i open csv file after writing. eg If i write test it displays correctly but when i write -test the value would be #NAME? when i open csv file. It is not a code issue but csv file automatically changes the value which starts with - to error(#NAME?) . How can i correct this programmatically. below is the code,

public class FileWriterTest {
    public static void main(String[] args) {
        BufferedWriter bufferedWriter = null;
        File file = new File("test.csv");
        try {
            bufferedWriter = new BufferedWriter(new FileWriter(file));
            List<String> records = getRecords();
            for (String record : records) {
                bufferedWriter.write(record);
                bufferedWriter.newLine();
            }
            bufferedWriter.flush();
            System.out.println("Completed writing data to a file.");
        } catch (IOException e) {
            e.printStackTrace();
        } finally {
            try {
                if (bufferedWriter != null)
                bufferedWriter.close();
            } catch (IOException e) {
                e.printStackTrace();
            }
        }
    }

    public static List<String> getRecords() {
        List<String> al = new ArrayList<String>();
        String s1 = "test";
        String s2 = "-test";
        al.add(s1);
        al.add(s2);
        return al;
    }
}

Could you please assist?

Answer 1

In the formal CSV standard , you can do this by using quotes ( " ) around the field value. They're a text delimiter (as opposed to other kinds of values, like numeric ones).

It sounds like you're using Excel. You may need to enable " as a text delimiter/indicator.

Update: If you double-click the .csv to open it in Excel, even this doesn't work. You have to open a workbook and then import the CSV data into it. (Pathetic, really...)

Answer 2

It's a problem with excel. When you open a CSV file in excel it tries to determine cell type automatically which usually fails. The CSV file is alright the editor is not ;)

You can either right click on the field, select Format Cell and there make it a text file (and you might need to remove the automatically inserted '=' sign). Or you can open the CSV file by going into Data - From Text/CSV and in the wizard select the proper column types.

Answer 3

I got a relatively old version of Excel (2007), and the following works perfectly:

Put the text between double quotes and preceed it with an equal sign.
Ie, -test becomes ="-test" .

You file will therefore look like this:

test1,test2,test3
test4,="-test5",test6

Works in Excel-2010 as well.

As Veselin Davidov mentioned, this will break the csv standard but I don't know whether that's a problem.