I am trying to write a hex editor. I'm trying to store values by writing a char to a text file. For some reason every decimal number 128-159 is being written or read (not sure which) as 63. I took measures to isolate the problem. Here's an example of it happening:
import java.io.BufferedReader;
import java.io.BufferedWriter;
import java.io.FileReader;
import java.io.FileWriter;
import java.io.IOException;
import java.io.File;
public class Why {
public static File file = new File("why.txt");
public static void main(String[] args) throws IOException {
if(!file.exists())
file.createNewFile();
BufferedWriter bw = new BufferedWriter(new FileWriter(file));
bw.write((char) 144);
bw.close();
BufferedReader br = new BufferedReader(new FileReader(file));
System.out.println(br.read());
br.close();
}
}
Any help is appreciated.
I figured it out using a FileOutputStream and FileInputStream. Thanks all.
When you use
FileReader
andFileWriter
, they will use the default encoding for your platform. That's almost always a bad idea.In your case, it seems that that encoding doesn't support U+0092, which is fairly reasonable given that it's a private use character - many encodings won't support that. I suspect you don't actually want
(char) 144
at all. If you really, really want to use that character, you should use an encoding which can encode all of Unicode - I'd recommend UTF-8.It's important to differentiate between text and binary, however - if you're really just interested in bytes, then you shouldn't use a reader or writer at all - use an
InputStream
and anOutputStream
. Hex editors are typically byte-oriented rather than text-oriented, although they may provide a text view as well (ideally with configurable encoding). If you want to know the exact bytes in the file, you should definitely be usingFileInputStream
.