This section provides a tutorial example on how to write a sample program, HexWriter.java, to convert encoded byte sequences to Hex values to help viewing encoded text files.
By running the sample program, UnicodeHello.java, presented in the previous section,
I got this text file saved in UTF-16BE encoding, hello.utf-16be.
The next question is how can I view and inspect this UTF-16BE encoded file.
Normal text editors will not able to show the content of this correctly.
I have two choices: using a Hex editor to open the file or convert the file to
Hex value file with a program.
I decide to write a simple Java program convert UTF-16BE byte sequences into Hex
decimal digits to allow me inspecting the code values of the saved characters. Remember
UTF-16BE encoding breaks the code values into two bytes directly without any changes in the value.
Here is a program to convert any data file into Hex decimal digits:
/**
* HexWriter.java
* Copyright (c) 2002 by Dr. Herong Yang
* This program allows you to convert and data file to a new data
* in Hex format with 16 bytes (32 Hex digits) per line.
*/
import java.io.*;
class HexWriter {
static char hexDigit[] = {'0', '1', '2', '3', '4', '5', '6', '7',
'8', '9', 'A', 'B', 'C', 'D', 'E', 'F'};
public static void main(String[] a) {
String inFile = a[0];
String outFile = a[1];
int bufSize = 16;
byte[] buffer = new byte[bufSize];
String crlf = System.getProperty("line.separator");
try {
FileInputStream in = new FileInputStream(inFile);
OutputStreamWriter out = new OutputStreamWriter(
new FileOutputStream(outFile));
int n = in.read(buffer,0,bufSize);
String s = null;
int count = 0;
while (n!=-1) {
count += n;
s = bytesToHex(buffer,0,n);
out.write(s);
out.write(crlf);
n = in.read(buffer,0,bufSize);
}
in.close();
out.close();
System.out.println("Number of input bytes: "+count);
} catch (IOException e) {
System.out.println(e.toString());
}
}
public static String bytesToHex(byte[] b, int off, int len) {
StringBuffer buf = new StringBuffer();
for (int j=0; j<len; j++)
buf.append(byteToHex(b[off+j]));
return buf.toString();
}
public static String byteToHex(byte b) {
char[] a = { hexDigit[(b >> 4) & 0x0f], hexDigit[b & 0x0f] };
return new String(a);
}
}
Compile this program and run it to convert hello.utf-16be:
