UTF-8 CJK characters not displaying in Java

问题

I've been reading up on Unicode and UTF-8 encoding for a while and I think I understand it, so hopefully this won't be a stupid question:

I have a file which contains some CJK characters, and which has been saved as UTF-8. I have various Asian language packs installed and the characters are rendered properly by other applications, so I know that much works.

In my Java app, I read the file as follows:

// Create objects
fis = new FileInputStream(new File("xyz.sgf"));
InputStreamReader is = new InputStreamReader(fis, Charset.forName("UTF-8"));
BufferedReader br = new BufferedReader(is);

// Read and display file contents
StringBuffer sb = new StringBuffer();
String line;
while ((line = br.readLine()) != null) {
    sb.append(line);
}
System.out.println(sb);

The output shows the CJK characters as '???'. A call to is.getEncoding() confirms that it is definitely using UTF-8. What step am I missing to make the characters appear properly? If it makes a difference, I'm looking at the output using the Eclipse console.

回答1:

System.out.println(sb);

The problem is the above line. This will encode character data using the default system encoding and emit the data to STDOUT. On many systems, this is a lossy process.

If you change the defaults, the encoding used by System.out and the encoding used by the console must match.

The only supported mechanism to change the default system encoding is via the operating system. (Some will advise using the file.encoding system property, but this is not supported and may have unintended side-effects.) You can use setOut to your own custom PrintStream:

PrintStream stdout = new PrintStream(System.out, autoFlush, encoding);

You can change the Eclipse console encoding via the Run configuration.

You can find a number of posts about the subject on my blog - via my profile.

回答2:

The following program prints CJK characters to the console using TextPad. To see the Korean Hangul and Japanese Hiragana I had to tell Java to change the print stream's encoding to EUC_KR and set the properties of TextPad's tool output window:

font is Arial Unicode MS
script is Hangul

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

class Hangul {

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

        // Change console encoding to Korean

        PrintStream out = new PrintStream(System.out, true, "EUC_KR");
        System.setOut(out);

        // Print sample to console

        String go_hello  = "가다 こんにちは";
        System.out.println(go_hello);
    }
}

Tool Output is:

가다 こんにちは

回答3:

Yeah, you need to change the encoding of the Eclipse console as explained in this how-to-display-chinese-character-in-eclipse-console article

回答4:

Depending on your platform, it is highly likely that your console (or windows CMD) does not support or use the UTF-8 characterset, and therefor converts all unmappable characters to a question mark.

On Windows for example CMD almost always uses WIN1252 or a similar single byte characterset.

来源：https://stackoverflow.com/questions/5965195/utf-8-cjk-characters-not-displaying-in-java

标签

java

utf-8

cjk