I have a String which is :
PRESIÓN MÁXIMA:
This string is in ISO-8859, I want to write it in an xml UTF-8 file :
I get its UTF-8 bytes values which seems good :
-61, -109 = C3 93 = Ó
-61, -127 = C3 81 = Á
But when I turn back this array of bytes into a String, the Ó is OK, but not the Á :
For some unknown reason the C3 81 become a C3 3F
There is something that I dont understand with encoding, at least I would expect both character to be wrong.
How can I fix / convert my String ?
Related
This question already has answers here:
How to convert byte array to hex format in Java
(4 answers)
Closed 2 years ago.
So i have a piece of code, which converted byte[] from a binary file into int[] which then went on to be converted to String.
Example: 02 09 1A would translate to "2926" using String.valueOf(byte);
But this is where the fun begins: the old Code already split up the array before it became String so it didn't matter. Now i have code which needs to somehow figure out if there is a 2 9 or 29... How can i get the String to
- stay in Hex instead of "switching" to decimal and
- keep the zeros in the string
so i can always grab the next two chars, figure out which info they display and go on?
Input: 05 06 1D 11 07 08 01 32 21 28 2F 20 2E 21 34 22 25 33 01 02 09 0A FF 0B 0C 2!(/ .!4"%3
ÿ
Current Output: 562917781503340473246335234375112910-11112
Expected Output: 05061D110708013221282F202E21342225330102090AFF0B0C
(Didn't put my old code in here since it's based on int which is crap)
If I understand correctly, you have a byte[] as input, and you want to output a string that is all those bytes, in hex form, joined together:
private static String byteArrayToString(byte[] byteArray) {
StringBuilder builder = new StringBuilder();
for (byte b : byteArray) {
int i = Byte.toUnsignedInt(b);
if (i < 16) {
builder.append("0");
}
builder.append(Integer.toHexString(i).toUpperCase());
}
return builder.toString();
}
Note the use of Byte.toUnsignedInt. This converts things like -1 the byte to the int 0xff. This is required because Java's bytes are signed.
Also note where I pad with 0. I only do this if the byte is a single digit in hex. i < 16 is the condition to check this.
Another way:
char[] hexVals = {'0', '1','2','3','4','5','6','7','8','9','A', 'B','C','D','E','F'};
byte[] bytes = {5, 6, (byte)0xAB, (byte)0xde}; // sample input
char[] output = new char[bytes.length*2];
// split each byte's hex digits into two chars
for(int i=0; i < bytes.length; i++) {
output[2*i] = hexVals[(bytes[i] >> 4) & 0xf]; // HO nibble
output[2*i+1] = hexVals[bytes[i] & 0xf]; // LO nibble
}
System.out.println(new String(output)); // 0506ABDE
I'm trying to convert a hex message to ascii
and I don't understand why I get this error
String final = (msg1 + " " + msg2 + " " + msg3);
byte[] s = DatatypeConverter.parseHexBinary(final);
String final = new String(s);
and this is the error I get :(the data is correct )
java.lang.IllegalArgumentException: hexBinary needs to be even-length: 4C 4B 4C 41 36 4C 31 45 32 48 41 37 32 32 31 36 31 FF
parseHexBinary is documented to take the input as defined by xsd:hexBinary.
This means the input string must contain only hexadecimal characters and always pairs. Your input stream contains space characters, that must be removed prior to parsing.
input = input.replaceAll(" +", "");
I have seen so many examples online but they are not exactly what Im looking for.
I have a .bin file that I'd like to POST to a server, so I am encoding and storing it as a string.
However, decoding it doesn't give the same result.
import org.apache.commons.codec.binary.Base64;
File file = getFileStreamPath(ENROLL_FILENAME);
byte[] bytes = loadFile(file);
byte[] encoded = Base64.encodeBase64(bytes);
for(int i =0; i< encoded.length; i++){
System.out.print(encoded[i]);
}
System.out.println();
String encodedString = new String(encoded); //send to sever and decode
System.out.println("Encode "+ encodedString);
byte[] decoded = Base64.decodeBase64(encodedString.getBytes());
for(int i =0; i< decoded.length; i++){
System.out.print(decoded[i]);
}
System.out.println();
Result:
System.out: 1147948656688781216567661069850481179071904876109571171018810311782109108117905086121997274112981108285908749119987170489081656565656565656565666511965678710365769951100112904878789087498010050537565651041221005010811081496648991101041191011036565666565656567122119891035265658065115656565686565656511081736565757366656565706565656565656565656565656565661016881656583857712010311971576582896765119491017310369786574119798181658665676580886569866574107788465658765661038082119698965748977756569906573119781148169976580115751026569986577657448103659965736578886569996566697811610369102657273755310365103656548781181036510465658579104656910565777374122119651086565527811281691086572107707165691106565119794365651126573897855656511465651157790656911465746979791196911865668178103816911965795675656569122656669787465691226566107795511965496574737768103694965668179841036550657473798811965516566103808465695365747778108119695365806573104816554656511580102656954656681759010369576566567886119666665737379831197066656765789711966686574103805211966736573111809065707665678979101103668165666980115103708365785677856570886567997970816697657289789011966976573858011381709965767378838166102656510779708166103656910778791196610465651077885817010465686580741036610665801117610265701096568657779103701146575698080656611565678178861196611565668979119103661156565119801001196611665737378107119661166573568097816612065658178978170122656885801121197050657665791081196653657248789065665565655276102119665565731077767103705665686980103817043657673801038167676580103777011971676568858011465717165688579122816772657399785011967776574737810211971776568103791068171806576997953119678265705278571036783656948808910371836568568010311967856573817610981718965699977100119679065805277111657197656973771161036798657377781161036710465801197811410371109656965797665671126566898085816711265756580108657111565778178791037111765777380106656712065657378102817112165698979110119711226577737869656756656777801066567476565103791101036865656565781148168656572737789103726665778980100816867656665805565686965711118011781687065738978120816872657252784881687665727780110816878657356791076572786577857976119688165655280114817281656969767711972876570111809711968906573103751011196890657369768481689965731157811365689965721118010211972996577107808010372104657873808511968106657277781081196810665728579116103721086574487376103681096567111798811968109657211177801036811265714879701196811365688980891197211765781038010110368118657156771076572118657077751001197248657811579731036851657552797910368536579107791141197257656910373821036843658069797065724765796580578165676510185801066569686585697487816971651018179901196972658611179761036574651004879114816977651006977688269817268798174105756874476571675081737353717976897773778950101661211017370876968701201077373101479067431225273759771741127765767454877010184577010275707110654677250107756897721197086101657110611212272821005267112113746811643677411652767511848536757514370118102827283103118721196711567854912170651041227088905572104864966121575269901176570102100557371538267113785169111685375727567771111211196890566770739772708011778705478556989885170887170757211452765284546749115676810310284718111711772117768367844379691021197471711076672110111686811770436911810772101103656566656589897310710410555998210880778212210210386865265985210211577995111578725185808680818510688107751138810777981118578731025287104102111821095265837551738811110210399871185285103111698853102115891064781978172527653781157987105488783675689111102567870731157910010248825411056874711989826611948875211985888965859776894875111111998012165119825489698782811037956103778282811038797801159065735279691046582568811110347471111031147211178120748982105736582545289107110537773771107785103515697565181995065738973656989978899986857119101786752901218011199547277109438077115497389768012185875347859079867398971218179112471078372895287886511597535211978501091117911111865856511711110174474873748948881084710789651191199899801118210573658566899985986689887612077871221021031011191105610751881071081
System.out: Encode 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
System.out: -84-19051151140329911110946100102116461111101211204670105110103101114112114105110116841011091121089711610100000001302900111151191051036777101109791191107408115119105103678011611412011212200400044-16981400-1644003000-99200-94100500000000000941300736749-1251-67122231394341130-100146502103215921210-103137602202415711240-10612401250-11613-831260-5101241270-649-460280-128139212801713-74131011410-2603201313-660330514-1241340-629-4903701413-91137012152413901214-80410-12213-20043011121001430-111145914702013-1271480-17100151017133615102514-170530-110121415302014780540-110149505502415761570-10913-1051570-168-123058011151241580201010216103113870650-1261475165032131070670-10415-290720-118151001750381412208001715-781820-33128018703914210900118131030900-12315-871920-781373095091421096073135909709138119704815380990-6111241102048125811070-95156001080361387010802214-6201080121511901090-12613-10901090-1131510501130413105111505315-8911180-8014-105012101251310001230141112701230-1191210112404915-12711260-7815-1270-1260-812231-12605315-841-12205314-510-1210-12113-370-1160-110131271-11605614-1151-1130-7314-250-11109413-100-11007715981-11006315-1250-1080-12411-1031-104071121190-1030-212-961-10206612-740-1010-12513-740-950-413-821-9006414440-8702215810-870-9615-1081-840-6013581-820-6215-1160-7902131251-7807014-971-770-6213160-6803515-1160-650814-980-640013-830-64011412981-630-58151170-6201615-200-60010615-710-590-12213-590-57012613-470-53011515-990-510-11314-1121-510-5914470-4801415-831-4806511511-42090151070-390-120101230-390-12711770-360-11713-880-360122151271-360-5515621-310-4615830-29011513-1050-29011714-741-270-998460-2604214950-26012212620-23010914230-2205415991-180-40151220-17011112-1121-17083101191-120-3714340-90-8214580-70-2314-811-30728700-20-1514201-10-3215-11021-2715-11613165989161-2814103171901446091-3514-831121-47121317162851-1123834-12539-16611100835-111-11445-125849-115-98739-120219732325833-17-3911-20-832-90-12238-109044-98-10621-28-321-14-1232662-126311051013-95-162187-1282658115292312010-102-11914-33-12638-341142-35711-35-222-9-47294047310-8497711420811521118123302111774712017-101-12821-9123321108110-9311918-128-740114-12650-116-8013-97220-122-12120-5-11523-9312317-123-921113-12340122-847-124-611912147-452511-8230-30-46963-11417-4924105130122314-3112618-7712200402496-11933-117-7317-108-1317-51-82187-12827-31-51211512313311171584-1220-11512110-8712112110-1231333-222-123-617-101-128184311423-95-82890-220-126-12723-27-524-113-12266412611-28-3714904522724724-95-11320-11714117-317-2212722-161771322-295239652645-11510-94-12115-561217-23-1272269814-1431769822104-5250-11414181617-1512232-1-632-8412213-60-10617-120-12817-21-12236-97-10985011520-12512726-1311628-40224321241051192715-3630524625-56-628-2411538-8-1344-44-12211633722-25-11255782271073614-89-71829-11422921126-25-11613-3810614-94-16202-223039-3837-11523-105-72431227112-617-120-128205-121201082223471922-51-830-6212736-3512137-5041432723-60-127-22629-73-10201212121-37-1162566629-77-11313-1453764-1738-1947478610210-107-9231672367130-69-122674451930124391810943288221-251162356-12723-62-19248911113-84-452617239123-62421112514-15018-41-2719-106-1330112-1246-9-4517627938566441673711-77-2714113021-131530-122-131012925-65-11329451030106-51713-791926-12421-126-1524-106-4223-72-525-12012636-131038-115-825-5011330-63122427110845-81-12711242718602724-204227921419117181991320-11582472-11129-92-12341-10312245-24-11347-13125151151261641-72344-11824100116133618248862878-105281131311-49-1015113-126197-182357127235152693-12530-27532-108-1017412326-109-23649-7372411013-74-1824115-12324-128-123493-71169102021-82488-11627114-123744-11116-94724-121224-119-1231497-430-83-2841-71-4550-62-97142012221-11-525-122-126269612576111118-6011623541182412012314-35437-71-244251-10850-65-4117-1-12323-95-1326-84-1832-119-11157-112884129-871233092413-252151241128-9694094151414-1221481-1272990-1530-64-7148212715-2911221112522-3311713-78-5215371728-79-4141124515-74-1728-68-69301728373324305773210103742-11542101-713108-12218-72-11625-74-53048-126769515-45-11221-125-1252581713114122258
Why are the byte arrays not the same?
I think they are the same. Note that the first line of your output is the encoded bytes, and 114 is the decimal ASCII code for 'r', 79 is the decimal ASCII code for 'O', 48 is the decimal ASCII code for '0' etc., so your first and second lines match and are what I'd expect given your code.
Then when you've decoded the values, the bytes are being sign-extended to ints, so -84 is actually 256 - 84 = 172, -19 is 256 - 19 = 237, 0 is 0, etc., and if you base64 decode the second line using command line tools:
$ base64 -d < x.bin | od -tu1 | head -2
0000000 172 237 0 5 115 114 0 32 99 111 109 46 100 102 116 46
0000020 111 110 121 120 46 70 105 110 103 101 114 112 114 105 110 116
You'll see things match. So I think everything's fine, it's just how and what you're printing that makes things look wrong.
As far as I see you print out encoded, encodedString and decoded but not bytes. Can you check bytewise whether your arrays are equal or not?
I'm trying to convert a string with special characters like É into a string with UTF-8 encoding. I tried doing this:
String str = "MARIE-HÉLÈNE";
byte sByte[] = str.getBytes("UTF-8");
str = new String(sByte,"UTF-8");
The problem is, when I do "É".getBytes("UTF-8"), I get 63 which is interpreted as '?' when it's being converted to a new string. How can I fix this issue?
EDIT: I also noticed that this issue was not reproducible on Eclipse, probably because the text file encoding is usually set to UTF-8.
I tried doing byte[] str = "MARIE-HÉLÈNE".getBytes("UTF-8") in http://www.javarepl.com/console.html and got the result byte[] str = [77, 65, 82, 73, 69, 45, 72, 63, 76, 63, 78, 69]
This kind of error happens when information about the encoding of the source file is not given to the compiler (javac) properly. If the encoding of your source file is UTF-8, compile the file like the following.
javac -encoding UTF-8 E.java
The following is another example for the case where the encoding of the source file is UTF-16 Big Endian.
javac -encoding UTF-16BE E.java
I've already confirmed that the program below properly shows "0xC3 0x89". So, there is no problem in your code.
public class E
{
public static void main(String[] args) throws Exception
{
byte[] bytes = "É".getBytes("UTF-8");
for (int i = 0; i < bytes.length; ++i)
{
System.out.format("0x%02X ", (byte)(bytes[i]));
}
System.out.println();
}
}
"É".getBytes("UTF-8") returns a byte[] of 2 bytes: c3 89.
"MARIE-HÉLÈNE" is 4d 41 52 49 45 2d 48 c3 89 4c c3 88 4e 45.
4d 41 52 49 45 2d 48 c3 89 4c c3 88 4e 45
M A R I E - H É L È N E
Converting the bytes back using new String(bytes,"UTF-8") will restore the original string.
How to convert ASCII to hexadecimal values in java.
For example:
ASCII: 31 32 2E 30 31 33
Hex: 12.013
You did not convert ASCII to hexadecimal value. You had char values in hexadecimal, and you wanted to convert it to a String is how I'm interpreting your question.
String s = new String(new char[] {
0x31, 0x32, 0x2E, 0x30, 0x31, 0x33
});
System.out.println(s); // prints "12.013"
If perhaps you're given the string, and you want to print its char as hex, then this is how to do it:
for (char ch : "12.013".toCharArray()) {
System.out.print(Integer.toHexString(ch) + " ");
} // prints "31 32 2e 30 31 33 "
You can also use the %H format string:
for (char ch : "12.013".toCharArray()) {
System.out.format("%H ", ch);
} // prints "31 32 2E 30 31 33 "
It's not entirely clear what you are asking, since your "hex" string is actually in decimal. I believe you are trying to take an ASCII string representing a double and to get its value in the form of a double, in which case using Double.parseDouble should be sufficient for your needs. If you need to output a hex string of the double value, then you can use Double.toHexString. Note you need to catch NumberFormatException, whenever you invoke one of the primitive wrapper class's parse functions.
byte[] ascii = {(byte)0x31, (byte)0x32, (byte)0x2E, (byte)0x30, (byte)0x31, (byte)0x33};
String decimalstr = new String(ascii,"US-ASCII");
double val = Double.parseDouble(decimalstr);
String hexstr = Double.toHexString(val);