Develop Reference

Encode to UTF-8. Encode character eg. ö to ö

I want to encode a string in Android to UTF-8. For example this string:
Grüne Ähren beißen Flöhe
to
Grüne Ãhren beiÃen Flöhe
But no matter what I do I encode ü to ü or ü to %C3%BC (online often called 'raw URL encode').
Found solutions to convert to byte[] or URI.toASCIIString(). But non of them work for me.
UPDATE
I am participating in the eBay partner network and try to concat a searchword to my partner url.
The people of eBay must use a wrong character set, as UTF-8 URL encoded string don't work.
A searchword with UTF-8 URL encoding
(Grüne Ähren beißen Flöhe
to
Gr%C3%BCne%20%C3%84hren%20bei%C3%9Fen%20Fl%C3%B6he)
comes out to this result in the eBay searchbox:
If I encode my searchword with ISO_8859_1 it works (Grüne Ãhren beiÃen Flöhe):
Thank you very much community

What you essentially want is to convert a String to it's byte representation according to UTF-8 and interpret these bytes using a different Charset, such as ISO-8859-1.
This is usually the cause of many problems. You want to intentionally do what most developers do incorrectly (or they simply ignore the problems of charsets).
Since you just need this to work, use this piece of code:
byte[] bytes = "Grüne Ähren beißen Flöhe".getBytes("UTF-8");
String result = new String(bytes, "ISO-8859-1");
see it at work here.

Java Encoding for "GB2312" CHARACTER ® replacing with question mark(?)

I'm trying to get encoded value using GB2312 characterset but I'm getting '? 'instead of '®'
Below is my sample code:
new String("Test ®".getBytes("GB2312"));
but I'm getting Test ? instead of Test ®.
Does any one faced this issue?
Java version- JDK6
Platform: Window 7
I'm not aware of Chinese character encoding so need suggestion.

For better understanding, the statement divided in two parts:
byte[] bytes = "Test ®".getBytes("GB2312"); // bytes, encoding the string to GB2312
new String(bytes); // back to string, using default encoding
Probably ® is not a valid GB2312 character, so it is converted to ?. See the result of
Charset.forName("GB2312").newEncoder().canEncode("®")
Based on documentation of getBytes:
The behavior of this method when this string cannot be encoded in the given charset is unspecified. The CharsetEncoder class should be used when more control over the encoding process is required.
which also suggest using CharsetEncoder.

Why do I have to encode a utf-8 parameter String to iso-Latin and then decode as utf-8 to get Java utf-8 String?

I have a Java servlet that takes a parameter String (inputString) that may contain Greek letters from a web page marked up as utf-8. Before I send it to a database I have to convert it to a new String (utf8String) as follows:
String utf8String = new String(inputString.getBytes("8859_1"), "UTF-8");
This works, but, as I hope will be appreciated, I hate doing something I don't understand, even if it works.
From the method description in the Java doc the getBytes() method "Encodes this String into a sequence of bytes using the named charset, storing the result into a new byte array" i.e. I am encoding it in 8859_1 — isoLatin. And from the Constructor description "Constructs a new String by decoding the specified array of bytes using the specified charset" i.e. decodes the byte array to utf-8.
Can someone explain to me why this is necessary?

My question is based on a misconception regarding the character set used for the HTTP request. I had assumed that because I marked up the web page from which the request was sent as UTF-8 the request would be sent as UTF-8, and so the Greek characters in the parameter sent to the servlet would be read as a UTF-8 String (‘inputString’ in my line of code) by the HttpRequest.getParameter() method. This is not the case.
HTTP requests are sent as ISO-8859-1 (POST) or ASCII (GET), which are generally the same. This is part of the URI Syntax specification — thanks to Andreas for pointing me to http://wiki.apache.org/tomcat/FAQ/CharacterEncoding where this is explained.
I had also forgotten that the encoding of Greek letters such as α for the request is URL-encoding, which produces %CE%B1. The getParameter() handles this by decoding it as two ISO-8859-1 characters, %CE and %B1 — Î and ± (I checked this).
I now understand why this needs to be turned into a byte array and the bytes interpreted as UTF-8. 0xCE does not represent a one-byte character in UTF-8 and hence it is addressed with the next byte, 0xB1, to be interpretted as α. (Î is 0xC3 0x8E and ± is 0xC2 0xB1 in UTF-8.)

When decoding, could you not create a class with a decoder method that takes the bytes [] as a parameter and
return it as a string? here is an example that i have used before.
public class Decoder
{
public String decode(byte[] bytes)
{
//Turns the bytes array into a string
String decodedString = new String(bytes);
return decodedString;
}
}
Try use this instead of .getBytes(). hope this works.

Converting string to byte[] returns wrong value (encoding?)

I read a byte[] from a file and convert it to a String:
byte[] bytesFromFile = Files.readAllBytes(...);
String stringFromFile = new String(bytesFromFile, "UTF-8");
I want to compare this to another byte[] I get from a web service:
String stringFromWebService = webService.getMyByteString();
byte[] bytesFromWebService = stringFromWebService.getBytes("UTF-8");
So I read a byte[] from a file and convert it to a String and I get a String from my web service and convert it to a byte[]. Then I do the following tests:
// works!
org.junit.Assert.assertEquals(stringFromFile, stringFromWebService);
// fails!
org.junit.Assert.assertArrayEquals(bytesFromFile, bytesFromWebService);
Why does the second assertion fail?

Other answers have covered the likely fact that the file is not UTF-8 encoded giving rise to the symptoms described.
However, I think the most interesting aspect of this is not that the byte[] assert fails, but that the assert that the string values are the same passes. I'm not 100% sure why this is, but I think the following trawl through the source code might give us the answer:
Looking at how new String(bytesFromFile, "UTF-8"); works - we see that the constructor calls through to StringCoding.decode()
This in turn, if supplied with tht UTF-8 character set, calls through to StringDecoder.decode()
This calls through to CharsetDecoder.decode() which decides what to do if the character is unmappable (which I guess will be the case if a non-UTF-8 character is presented)
In this case it uses an action defined by
private CodingErrorAction unmappableCharacterAction
= CodingErrorAction.REPORT;
Which means that it still reports the character it has decoded, even though it's technically unmappable.
I think this means that even when the code gets an umappable character, it substitutes its best guess - so I'm guessing that its best guess is correct and hence the String representations are the same under comparison, but the byte[] are no longer the same.
This hypothesis is kind of supported by the fact that the catch block for CharacterCodingException in StringCoding.decode() says:
} catch (CharacterCodingException x) {
// Substitution is always enabled,
// so this shouldn't happen

I don't understand it fully, but here's what I get so fare:
The problem is that the data contains some bytes which are not valid UTF-8 bytes as I know by the following check:
// returns false for my data!
public static boolean isValidUTF8(byte[] input) {
CharsetDecoder cs = Charset.forName("UTF-8").newDecoder();
try {
cs.decode(ByteBuffer.wrap(input));
return true;
}
catch(CharacterCodingException e){
return false;
}
}
When I change the encoding to ISO-8859-1 everything works fine. The strange thing (which a don't understand yet) is why my conversion (new String(bytesFromFile, "UTF-8");) doesn't throw any exception (like my isValidUTF8 method), although the data is not valid UTF-8.
However, I think I will go another and encode my byte[] in a Base64 string as I don't want more trouble with encoding.

The real problem in your code is that you don't know what the real file encoding.
When you read the string from the web service you get a sequence of chars; when you convert the string from chars to bytes the conversion is made right because you specify how to transform char in bytes with a specific encoding ("UFT-8"). when you read a text file you face a different problem. You have a sequence of bytes that needs to be converted to chars. In order to do it properly you must know how the chars where converted to bytes i.e. what is the file encoding. For files (unless specified) it's a platform constants; on windows the file are encoded in win1252 (which is very close to ISO-8859-1); on linux/unix it depends, I think UTF8 is the default.
By the way the web service call did a decond operation under the hood; the http call use an header taht defins how chars are encoded, i.e. how to read the bytes form the socket and transform then to chars. So calling a SOAP web service gives you back an xml (which can be marshalled into a Java object) with all the encoding operations done properly.
So if you must read chars from a File you must face the encoding issue; you can use BASE64 as you stated but you lose one of the main benefits of text files: the are human readable, easing debugging and developing.

Convert and Display the UTF8 Encoded String

I have a JSON response which i want to store in DB and display in text view or edit text. This json response is encoded by UTF-8 format.
Response is somthing like
"currencies": [[0,"RUR"," ",1,0],[1,"EUR","â¬",1.44,100],[2,"GBP","£",1.6,100],[3,"JPY","Â¥",0.0125,100],[4,"AUD","$",1.1,100]]}
where â¬,£,Â¥ are currency symbol. I have to decode this and then display. This symbols are symbol in Unicode (transferrred as UTF8). How can I convert this encoded symbol. Plz help.
I tried this but it didnt works:
byte[] b = stringSymbol.getBytes("UTF-8"); // â¬,£,Â¥
final String str = new String(b);

You're showing the text with non-currency symbols... it's as if you're taking the original text, then encoding that as UTF-8, then decoding it as ISO-8859-1.
It's just text - you shouldn't need to do anything to it afterwards, and you should never see it in this broken format. If you have to convert the text back to bytes and then to a string again, that means you've already lost, basically.
Check the headers on the HTTP response which returns the JSON - I suspect you'll find that it's claiming the data is ISO-8859-1 rather than UTF-8. The actual encoding has to match the encoding that's specified in the headers, otherwise you end up with this sort of effect.
Another possibility is that whatever's returning the JSON is accurately giving you the data that it knows about, and that the data is broken upstream. You should follow the data step by step (assuming you own all the links in the chain) until you can see where you're first encountering this brokenness.