Byte Encodings and Strings (The Java™ Tutorials ...
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Byte Encodings and Strings ... If a byte array contains non-Unicode text, you can convert the text to Unicode with one of the String constructor methods.
Documentation
TheJava™Tutorials
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WorkingwithText
CheckingCharacterProperties
ComparingStrings
PerformingLocale-IndependentComparisons
CustomizingCollationRules
ImprovingCollationPerformance
Unicode
Terminology
SupplementaryCharactersasSurrogates
CharacterandStringAPIs
SampleUsage
DesignConsiderations
MoreInformation
DetectingTextBoundaries
AbouttheBreakIteratorClass
CharacterBoundaries
WordBoundaries
SentenceBoundaries
LineBoundaries
ConvertingLatinDigitstoOtherUnicodeDigits
ConvertingNon-UnicodeText
ByteEncodingsandStrings
CharacterandByteStreams
NormalizingText
WorkingwithBidirectionalTextwiththeJTextComponentClass
Trail:Internationalization
Lesson:WorkingwithText
Section:ConvertingNon-UnicodeText
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TheJavaTutorialshavebeenwrittenforJDK8.Examplesandpracticesdescribedinthispagedon'ttakeadvantageofimprovementsintroducedinlaterreleasesandmightusetechnologynolongeravailable.SeeJavaLanguageChangesforasummaryofupdatedlanguagefeaturesinJavaSE9andsubsequentreleases.SeeJDKReleaseNotesforinformationaboutnewfeatures,enhancements,andremovedordeprecatedoptionsforallJDKreleases.
ByteEncodingsandStrings
Ifabytearraycontainsnon-Unicodetext,youcanconvertthetexttoUnicodewithoneoftheStringconstructormethods.Conversely,youcanconvertaStringobjectintoabytearrayofnon-UnicodecharacterswiththeString.getBytesmethod.Wheninvokingeitherofthesemethods,youspecifytheencodingidentifierasoneoftheparameters.
TheexamplethatfollowsconvertscharactersbetweenUTF-8andUnicode.UTF-8isatransmissionformatforUnicodethatissafeforUNIXfilesystems.Thefullsourcecodefortheexampleisinthefile
StringConverter.java.
TheStringConverterprogramstartsbycreatingaStringcontainingUnicodecharacters:
Stringoriginal=newString("A"+"\u00ea"+"\u00f1"+"\u00fc"+"C");
Whenprinted,theStringnamedoriginalappearsas:
AêñüC
ToconverttheStringobjecttoUTF-8,invokethegetBytesmethodandspecifytheappropriateencodingidentifierasaparameter.ThegetBytesmethodreturnsanarrayofbytesinUTF-8format.TocreateaStringobjectfromanarrayofnon-Unicodebytes,invoketheStringconstructorwiththeencodingparameter.Thecodethatmakesthesecallsisenclosedinatryblock,incasethespecifiedencodingisunsupported:
try{
byte[]utf8Bytes=original.getBytes("UTF8");
byte[]defaultBytes=original.getBytes();
StringroundTrip=newString(utf8Bytes,"UTF8");
System.out.println("roundTrip="+roundTrip);
System.out.println();
printBytes(utf8Bytes,"utf8Bytes");
System.out.println();
printBytes(defaultBytes,"defaultBytes");
}
catch(UnsupportedEncodingExceptione){
e.printStackTrace();
}
TheStringConverterprogramprintsoutthevaluesintheutf8BytesanddefaultBytesarraystodemonstrateanimportantpoint:Thelengthoftheconvertedtextmightnotbethesameasthelengthofthesourcetext.SomeUnicodecharacterstranslateintosinglebytes,othersintopairsortripletsofbytes.
TheprintBytesmethoddisplaysthebytearraysbyinvokingthebyteToHexmethod,whichisdefinedinthesourcefile,
UnicodeFormatter.java.HereistheprintBytesmethod:
publicstaticvoidprintBytes(byte[]array,Stringname){
for(intk=0;k
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