[java] Carriage Return\Line feed in Java

I have created a text file in Unix environment using Java code.

For writing the text file I am using java.io.FileWriter and BufferedWriter. And for newline after each row I am using bw.newLine() method (where bw is object of BufferedWriter).

And I'm sending that text file by attaching in mail from Unix environment itself (automated that using Unix commands).

My issue is, after I download the text file from mail in a Windows system, if I opened that text file the data is not properly aligned. newline() character is not working, I think so.

I want same text file alignment as it is in Unix environment, if I opened the text file in Windows environment also.

How do I resolve the problem?

Java code below for your reference (running in Unix environment):

File f = new File(strFileGenLoc);
BufferedWriter bw = new BufferedWriter(new FileWriter(f, false));
rs = stmt.executeQuery("select * from jpdata");
while ( rs.next() ) {
    bw.write(rs.getString(1)==null? "":rs.getString(1));
    bw.newLine();
}

The method newLine() ensures a platform-compatible new line is added (0Dh 0Ah for DOS, 0Dh for older Macs, 0Ah for Unix/Linux). Java has no way of knowing on which platform you are going to send the text. This conversion should be taken care of by the mail sending entities.

Don't know who looks at your file, but if you open it in wordpad instead of notepad, the linebreaks will show correct. In case you're using a special file extension, associate it with wordpad and you're done with it. Or use any other more advanced text editor.

If I understand you right, we talk about a text file attachment. Thats unfortunate because if it was the email's message body, you could always use "\r\n", referring to http://www.faqs.org/rfcs/rfc822.html

But as it's an attachment, you must live with system differences. If I were in your shoes, I would choose one of those options:

a) only support windows clients by using "\r\n" as line end.

b) provide two attachment files, one with linux format and one with windows format.

c) I don't know if the attachment is to be read by people or machines, but if it is people I would consider attaching an HTML file instead of plain text. more portable and much prettier, too :)

Encapsulate your writer to provide char replacement, like this:

public class WindowsFileWriter extends Writer {

    private Writer writer;

    public WindowsFileWriter(File file) throws IOException {
        try {
            writer = new OutputStreamWriter(new FileOutputStream(file), "ISO-8859-15");
        } catch (UnsupportedEncodingException e) {
            writer = new FileWriter(logfile);
        }
    }

    @Override
    public void write(char[] cbuf, int off, int len) throws IOException {
        writer.write(new String(cbuf, off, len).replace("\n", "\r\n"));
    }

    @Override
    public void flush() throws IOException {
        writer.flush();
    }

    @Override
    public void close() throws IOException {
        writer.close();
    }

}

bw.newLine(); cannot ensure compatibility with all systems.

If you are sure it is going to be opened in windows, you can format it to windows newline.

If you are already using native unix commands, try unix2dos and convert teh already generated file to windows format and then send the mail.

If you are not using unix commands and prefer to do it in java, use ``bw.write("\r\n")` and if it does not complicate your program, have a method that finds out the operating system and writes the appropriate newline.