Convert fom \uXXXX to %XX%XX

[servoloro]

*Newbie question*
I have to convert a string from the format (how it's called ?)
\uXXXX
to (again:how it's called ?)
%XX%XX
i.e. from \u00dc to %C3%9C.
Apart from doing a dumb replaceAll
s=s.replaceAll("\u00dc", "%C3%9C");
I'm sure there is a smarter way.
Not knowing the names of the formats Google didn't help me :-(
Could someone give me hints/directions ?
TIA

[servoloro]

Sorry it is:

> s=s.replaceAll("\\\\u00dc", "%C3%9C");

On 2/8/23 10:31, servoloro wrote:
> *Newbie question*
> I have to convert a string from the format (how it's called ?)
> \uXXXX
> to (again:how it's called ?)
> %XX%XX
> i.e. from \u00dc to %C3%9C.
> Apart from doing a dumb replaceAll

[e.d.pro...@gmail.com]

If you google "\u00dc" you'll see it's called unicode, expressed as a Java String, that code specifically being "latin capitol letter U with diaersis".
Note if you want to replace all occurrences of a single string within a string, call the .replace method. Use .replaceAll if you need the replacement value to be a regex.
If you google "%C3%9C" you'll see it's also unicode, expressed in url encoding.
If you google "java unicode url encode" you'll see some different ways to do that, depending on your use case. Is it for a domain name? query string parameter? web page label value? is there a framework? more context is required to get specific on the solution.
If you know that's the only character you'll need to convert, the replace method could suffice, otherwise you'll likely want to call an API encode method.

[servoloro]

On 2/8/23 13:28, e.d.pro...@gmail.com wrote:
> If you google "\u00dc" you'll see it's called unicode, expressed as a Java String, that code specifically being "latin capitol letter U with diaersis".

> ...
THANKS !

[Arne Vajhøj]

On 2/8/2023 4:33 AM, servoloro wrote:
> On 2/8/23 10:31, servoloro wrote:
>> *Newbie question*
>> I have to convert a string from the format (how it's called ?)
>> \uXXXX
>> to (again:how it's called ?)
>> %XX%XX
>> i.e. from \u00dc to %C3%9C.
>> Apart from doing a dumb replaceAll
>> I'm sure there is a smarter way.
>> Not knowing the names of the formats Google didn't help me :-(
>> Could someone give me hints/directions ?
> Sorry it is:
> > s=s.replaceAll("\\\\u00dc", "%C3%9C");

There are a lot complications here.
- "\u00dc" is 1 char but "\\u00dc" is 6 chars
- you seems to have an implicit assumption about UTF-8 encoding
- the type of encode is generally known as URL encode, but
there is some ambiguity in that like whether you want
spaces as is or converted to plus sign

But the code below should illustrate a lot.

Arne

import java.io.UnsupportedEncodingException;
import java.net.URLEncoder;
import java.util.regex.Matcher;
import java.util.regex.Pattern;

public class UFun {
private static String encode_hack(String s) {
return s.replace("\u00dc", "%C3%9C")
.replace("\u00c6", "%C3%86")
.replace("\u00d8", "%C3%98")
.replace("\u00c5", "%C3%85")
.replace("\u00e6", "%C3%A6")
.replace("\u00f8", "%C3%B8")
.replace("\u00e5", "%C3%A5");
}
private static String encode_manual(String s) throws
UnsupportedEncodingException {
StringBuilder sb = new StringBuilder();
for(byte b : s.getBytes("UTF-8")) {
if(32 <= b && b < 127) {
sb.append((char)b);
} else if (0 <= b && b < 10) {
sb.append("%0");
sb.append(Integer.toHexString(b).toUpperCase());
} else {
sb.append('%');
sb.append(Integer.toHexString(b & 0xFF).toUpperCase());
}
}
return sb.toString();
}
private static String encode_builtin(String s) throws
UnsupportedEncodingException {
return URLEncoder.encode(s, "UTF-8").replace("+", "
").replace("%3A", ":");
}
private static void test1(String s) throws
UnsupportedEncodingException {
String s2a = encode_hack(s);
System.out.printf("%s -> %s\n", s, s2a);
String s2b = encode_manual(s);
System.out.printf("%s -> %s\n", s, s2b);
String s2c = encode_builtin(s);
System.out.printf("%s -> %s\n", s, s2c);
}
private static final Pattern p =
Pattern.compile("\\\\u([0-9A-Fa-f]{4})");
private static String decode(String s) {
Matcher m = p.matcher(s);
StringBuffer res = new StringBuffer();
while (m.find()) {
m.appendReplacement(res, Character.toString((char)
Integer.parseInt(m.group(1), 16)));
}
m.appendTail(res);
return res.toString();
}
private static String decode_encode_hack(String s) {
return encode_hack(decode(s));
}
private static String decode_encode_manual(String s) throws
UnsupportedEncodingException {
return encode_manual(decode(s));
}
private static String decode_encode_builtin(String s) throws
UnsupportedEncodingException {
return encode_builtin(decode(s));
}
private static void test2(String s) throws
UnsupportedEncodingException {
String s2a = decode_encode_hack(s);
System.out.printf("%s -> %s\n", s, s2a);
String s2b = decode_encode_manual(s);
System.out.printf("%s -> %s\n", s, s2b);
String s2c = decode_encode_builtin(s);
System.out.printf("%s -> %s\n", s, s2c);
}
public static void main(String[] args) throws
UnsupportedEncodingException {
test1("This is \u00dc and Ü and Danish: ÆØÅæøå");
test2("This is \\u00dc and Ü and Danish: ÆØÅæøå");
}
}