LingPipe Blog

I finally figured out how to have my Java programs write Unicode to a Windows shell and show up looking the right way. Here’s the final result (click to enlarge):

And here’s how I did it.

1. Fire Up PowerShell ISE

My new Windows 7 Professional notebook comes with an application called PowerShell ISE (make sure to run the ISE version; the unmarked one is more like DOS and has the same problems noted below). The “ISE” is for “integrated scripting environment”.

It defaults to Consolas font, which looks a lot like Lucida console.

2. Set Character Encoding to UTF-8

This’ll set the DOS character encoding to be UTF-8.

> chcp 65001
Active code page: 65001

3. Set Java System.out to UTF-8

Before writing to System.out, Java’s constant for the standard output, you’ll need to set it up to use UTF-8. It’s a one-liner.

System.setOut(new PrintStream(System.out,true,"UTF-8"));

The true value enables auto-flushing, which is a good idea for standard output.

Demo Program

Here’s a simple test program (the backslash escapes are Java literals for Unicode code points).

import java.io.PrintStream;
import java.io.UnsupportedEncodingException;

public class Test {

    public static void main(String[] args) 
        throws UnsupportedEncodingException {

        PrintStream utf8Out
            = new PrintStream(System.out,false,"UTF-8");
        System.setOut(utf8Out);

        System.out.println("English: Hello");
        System.out.println("French: D\u00E9j\u00E0 vu");
        System.out.println("Tamil: \u0B92");
        System.out.println("Han: \u4E52");
    }

}

You can see the output in action in the screen dumps at the top of this post.

Problems with DOS

The DOS shell will let you set the character encoding and change the font to Lucida console. But it oddly duplicates characters at the end of lines if the lines contain non-ASCII code points. You can see this on the example. And it can’t handle the Tamil or Han characters.

This entry was posted on July 6, 2010 at 6:27 pm and is filed under Carp's Blog, Java, LingPipe in Use. You can follow any responses to this entry through the RSS 2.0 feed. You can leave a response, or trackback from your own site.