Java App : Unable to read iso-8859-1 encoded file correctly

问题

I have a file which is encoded as iso-8859-1, and contains characters such as ô .

I am reading this file with java code, something like:

File in = new File("myfile.csv");
InputStream fr = new FileInputStream(in);
byte[] buffer = new byte[4096];
while (true) {
    int byteCount = fr.read(buffer, 0, buffer.length);
    if (byteCount <= 0) {
        break;
    }

    String s = new String(buffer, 0, byteCount,"ISO-8859-1");
    System.out.println(s);
}

However the ô character is always garbled, usually printing as a ? .

I have read around the subject (and learnt a little on the way) e.g.

http://www.joelonsoftware.com/articles/Unicode.html
http://bugs.sun.com/bugdatabase/view_bug.do?bug_id=4508058
http://www.ingrid.org/java/i18n/utf-16/

but still can not get this working

Interestingly this works on my local pc (xp) but not on my linux box.

I have checked that my jdk supports the required charsets (they are standard, so this is no suprise) using :

System.out.println(java.nio.charset.Charset.availableCharsets());

回答1:

I suspect that either your file isn't actually encoded as ISO-8859-1, or System.out doesn't know how to print the character.

I recommend that to check for the first, you examine the relevant byte in the file. To check for the second, examine the relevant character in the string, printing it out with

 System.out.println((int) s.getCharAt(index));

In both cases the result should be 244 decimal; 0xf4 hex.

See my article on Unicode debugging for general advice (the code presented is in C#, but it's easy to convert to Java, and the principles are the same).

In general, by the way, I'd wrap the stream with an InputStreamReader with the right encoding - it's easier than creating new strings "by hand". I realise this may just be demo code though.

EDIT: Here's a really easy way to prove whether or not the console will work:

 System.out.println("Here's the character: \u00f4");

回答2:

Parsing the file as fixed-size blocks of bytes is not good --- what if some character has a byte representation that straddles across two blocks? Use an InputStreamReader with the appropriate character encoding instead:

 BufferedReader br = new BufferedReader(
         new InputStreamReader(
         new FileInputStream("myfile.csv"), "ISO-8859-1");

 char[] buffer = new char[4096]; // character (not byte) buffer 

 while (true)
 {
      int charCount = br.read(buffer, 0, buffer.length);

      if (charCount == -1) break; // reached end-of-stream 

      String s = String.valueOf(buffer, 0, charCount);
      // alternatively, we can append to a StringBuilder

      System.out.println(s);
 }

Btw, remember to check that the unicode character can indeed be displayed correctly. You could also redirect the program output to a file and then compare it with the original file.

As Jon Skeet suggests, the problem may also be console-related. Try System.console().printf(s) to see if there is a difference.

回答3:

@Joel - your own answer confirms that the problem is a difference between the default encoding on your operating system (UTF-8, the one Java has picked up) and the encoding your terminal is using (ISO-8859-1).

Consider this code:

public static void main(String[] args) throws IOException {
    byte[] data = { (byte) 0xF4 };
    String decoded = new String(data, "ISO-8859-1");
    if (!"\u00f4".equals(decoded)) {
        throw new IllegalStateException();
    }

    // write default charset
    System.out.println(Charset.defaultCharset());

    // dump bytes to stdout
    System.out.write(data);

    // will encode to default charset when converting to bytes
    System.out.println(decoded);
}

By default, my Ubuntu (8.04) terminal uses the UTF-8 encoding. With this encoding, this is printed:

UTF-8
?ô

If I switch the terminal's encoding to ISO 8859-1, this is printed:

UTF-8
ôÃ´

In both cases, the same bytes are being emitted by the Java program:

5554 462d 380a f4c3 b40a

The only difference is in how the terminal is interpreting the bytes it receives. In ISO 8859-1, ô is encoded as 0xF4. In UTF-8, ô is encoded as 0xC3B4. The other characters are common to both encodings.

回答4:

If you can, try to run your program in debugger to see what's inside your 's' string after it is created. It is possible that it has correct content, but output is garbled after System.out.println(s) call. In that case, there is probably mismatch between what Java thinks is encoding of your output and character encoding of your terminal/console on Linux.

回答5:

Basically, if it works on your local XP PC but not on Linux, and you are parsing the exact same file (i.e. you transferred it in a binary fashion between the boxes), then it probably has something to do with the System.out.println call. I don't know how you verify the output, but if you do it by connecting with a remote shell from the XP box, then there is the character set of the shell (and the client) to consider.

Additionally, what Zach Scrivena suggests is also true - you cannot assume that you can create strings from chunks of data in that way - either use an InputStreamReader or read the complete data into an array first (obviously not going to work for a large file). However, since it does seem to work on XP, then I would venture that this is probably not your problem in this specific case.

来源：https://stackoverflow.com/questions/498636/java-app-unable-to-read-iso-8859-1-encoded-file-correctly

标签

java

encoding

character-encoding

iso-8859-1