Develop Reference

Java String to UCS2 encoding for Letters with Accents

I have a requirement for encoding a String that contains foreign characters eg. letters with accents to UCS2 characters and have the following piece of code working for normal english letters.
String encodeAsUCS2(String test) throws UnsupportedEncodingException{
byte[] bytes = test.getBytes("UTF-16BE");
StringBuilder sb = new StringBuilder();
for (byte b : bytes) {
sb.append(String.format("%02X", b));
}
return sb.toString();
}
That outputs hexadecimal sequence of UCS2/UTF16 bytes
eg. hello = 00680065006C006C006F
It runs into an issue with the letters that have accents/foreign characters and displays the value as FFFD which is in the Specials table and is used to indicate problems when a system is unable to render a stream of data to a correct symbol.
Any work around for this?

How to convert byte[] to String in Java?

There are some SO quetions but no helped me. I would like to convert byte[] from org.apache.commons.codec.digest.HmacUtils to String. This code produces some weird output:
final String value = "value";
final String key = "key";
byte[] bytes = HmacUtils.hmacSha1(key, value);
String s = new String(bytes);
What am I doing wrong?

Try to use:
String st = HmacUtils.hmacSha1Hex(key, value);

First, the result of hmacSha1 would produce a digest, not not a clear String. Besides, you may have to specify an encoding format, for example
String s = new String(bytes, "US-ASCII");
or
String s = new String(bytes, "UTF-8");

For a more general solution, if you don't have HmacUtils available:
// Prepare a buffer for the string
StringBuilder builder = new StringBuilder(bytes.length*2);
// Iterate through all bytes in the array
for(byte b : bytes) {
// Convert them into a hex string
builder.append(String.format("%02x",b));
// builder.append(String.format("%02x",b).toUpperCase()); // for upper case characters
}
// Done
String s = builder.toString();
To explain your problem:
You are using a hash function. So a hash is usually an array of bytes which should look quite random.
If you use new String(bytes) you try to create a string from these bytes. But Java will try to convert the bytes to characters.
For example: The byte 65 (hex 0x41) becomes the letter 'A'. 66 (hex 0x42) the letter 'B' and so on. Some numbers can't be converted into readable characters. Thats why you see strange characters like '�'.
So new String(new byte[]{0x41, 0x42, 0x43}) will become 'ABC'.
You want something else: You want each byte converted into a 2 digit hex String (and append these strings).
Greetings!

You may need to have an encoding format. Check out this link here.
UTF-8 byte[] to String

How to convert a string UTF-8 to ANSI in java?

I have a string in UTF-8 format. I want to convert it to clean ANSI format. How to do that?

You could use a java function like this one here to convert from UTF-8 to ISO_8859_1 (which seems to be a subset of ANSI):
private static String convertFromUtf8ToIso(String s1) {
if(s1 == null) {
return null;
}
String s = new String(s1.getBytes(StandardCharsets.UTF_8));
byte[] b = s.getBytes(StandardCharsets.ISO_8859_1);
return new String(b, StandardCharsets.ISO_8859_1);
}
Here is a simple test:
String s1 = "your utf8 stringáçﬠ";
String res = convertFromUtf8ToIso(s1);
System.out.println(res);
This prints out:
your utf8 stringáç?
The ﬠ character gets lost because it cannot be represented with ISO_8859_1 (it has 3 bytes when encoded in UTF-8). ISO_8859_1 can represent á and ç.

You can do something like this:
new String("your utf8 string".getBytes(Charset.forName("utf-8")));
in this format 4 bytes of UTF8 converts to 8 bytes of ANSI

Converting UTF-8 to ANSI is not possible generally, because ANSI only has 128 characters (7 bits) and UTF-8 has up to 4 bytes. That's like converting long to int, you lose information in most cases.

Windows-1251 to UTF-8 codes

I have code of character in Windows-1251 code table.
How i can get code of this character in UTF-8 code table?
For example i have character 'А' with coded in Windows-1251 equals 192, appropriate utf-8 code equals 1040
How i can to initialize Character or char in Java with code 192 from Windows-1251 code table?
char c = (char)192; //how to specify the encoding ?

To convert a byte[] encoding in one character encoding to another you can do
public static byte[] convertEncoding(byte[] bytes, String from, String to) {
return new String(bytes, from).getBytes(to);
}

Convert "php unicode" to character

How can I convert so called "php unicode"(link to php unicode) to normal character via Java? Example \xEF\xBC\xA1 -> A. Are there any embedded methods in jdk or should I use regex for this conversion?

You first need to get the bytes out of the string into a byte-array without changing them and then decode the byte-array as a UTF-8 string.
The simplest way to get the string into a byte array is to encode it using ISO-8859-1 which map every character with a unicode value less than 256 to a byte with the same value (or the equivalent negative)
String phpUnicode = "\u00EF\u00BC\u00A1"
byte[] bytes = phpUnicode.getBytes("ISO-8859-1"); // maps to bytes with the same ordinal value
String javaString = new String(bytes, "UTF-8");
System.out.println(javaString);
Edit
The above converts the UTF-8 to the Unicode character. If you then want to convert it to a reasonable ASCII equivalent, there's no standard way of doing that: but see this question
Edit
I assumed that you had a string containing characters that had the same ordinal value as the UTF-8 sequence but you indicate that your string literally contains the escape sequence, as in:
String phpUnicode = "\\xEF\\xBC\\xA1";
The JDK doesn't have any built-in methods to convert Strings like this so you'll need to use your own regex. Since we ultimately want to convert a utf-8 byte-sequence into a String, we need to set up a byte-array, using maybe:
Pattern oneChar = Pattern.compile("\\\\x([0-9A-F]{2})|(.)", Pattern.CASE_INSENSITIVE | Pattern.DOTALL);
Matcher matcher = oneChar.matcher(phpUnicode);
ByteArrayOutputStream bytes = new ByteArrayOutputStream();
while (matcher.find()) {
int ch;
if (matcher.group(1) == null) {
ch = matcher.group(2).charAt(0);
}
else {
ch = Integer.parseInt(matcher.group(1), 16);
}
bytes.write((int) ch);
}
String javaString = new String(bytes.toByteArray(), "UTF-8");
System.out.println(javaString);
This will generate a UTF-8 stream by converting \xAB sequences. This UTF-8 stream is then converted to a Java string. It's important to note that any character that is not part of an escape sequence will be converted to a byte equivalent to to the low-order 8 bites of the unicode character. This works fine for ascii but can cause transcoding problems for non-ascii characters.
#McDowell:
The sequence:
String phpUnicode = "\u00EF\u00BC\u00A1"
byte[] bytes = phpUnicode.getBytes("ISO-8859-1");
creates a byte array containing as many bytes as the original string has characters and for each character with a unicode value below 256, the same numeric value is stored in the byte-array.
The character FULLWIDTH LATIN CAPITAL LETTER A (U+FF41) is not present in the original String so the fact that it is not in ISO-8859-1 is irrelevant.
I know that transcoding bugs can occur when you convert characters to bytes that's why I said that ISO-8859-1 would only "map every character with a unicode value less than 256 to a byte with the same value"

The character in question is U+FF21 (FULLWIDTH LATIN CAPITAL LETTER A). The PHP form (\xEF\xBC\xA1) is a UTF-8 encoded octet sequence.
In order to decode this sequence to a Java String (which is always UTF-16), you would use the following code:
// \xEF\xBC\xA1
byte[] utf8 = { (byte) 0xEF, (byte) 0xBC, (byte) 0xA1 };
String utf16 = new String(utf8, Charset.forName("UTF-8"));
// print the char as hex
for(char ch : utf16.toCharArray()) {
System.out.format("%02x%n", (int) ch);
}
If you want to decode the data from a string literal you could use code of this form:
public static void main(String[] args) {
String utf16 = transformString("This is \\xEF\\xBC\\xA1 string");
for (char ch : utf16.toCharArray()) {
System.out.format("%s %02x%n", ch, (int) ch);
}
}
private static final Pattern SEQ
= Pattern.compile("(\\\\x\\p{Alnum}\\p{Alnum})+");
private static String transformString(String encoded) {
StringBuilder decoded = new StringBuilder();
Matcher matcher = SEQ.matcher(encoded);
int last = 0;
while (matcher.find()) {
decoded.append(encoded.substring(last, matcher.start()));
byte[] utf8 = toByteArray(encoded.substring(matcher.start(), matcher.end()));
decoded.append(new String(utf8, Charset.forName("UTF-8")));
last = matcher.end();
}
return decoded.append(encoded.substring(last, encoded.length())).toString();
}
private static byte[] toByteArray(String hexSequence) {
byte[] utf8 = new byte[hexSequence.length() / 4];
for (int i = 0; i < utf8.length; i++) {
int offset = i * 4;
String hex = hexSequence.substring(offset + 2, offset + 4);
utf8[i] = (byte) Integer.parseInt(hex, 16);
}
return utf8;
}