그만큼 자바 문자열 toUpperCase() 메소드는 문자열을 대문자로 반환합니다. 즉, 문자열의 모든 문자를 대문자로 변환합니다.

toUpperCase() 메서드는 toUpperCase(Locale.getDefault()) 메서드와 동일하게 작동합니다. 내부적으로 기본 로케일을 사용합니다.

내부 구현

 public String toUpperCase(Locale locale) { if (locale == null) { throw new NullPointerException(); } int firstLower; final int len = value.length; /* Now check if there are any characters that need to be changed. */ scan: { for (firstLower = 0 ; firstLower = Character.MIN_HIGH_SURROGATE) &amp;&amp; (c <= character.max_high_surrogate)) { c="codePointAt(firstLower);" srccount="Character.charCount(c);" } else int uppercasechar="Character.toUpperCaseEx(c);" if ((uppercasechar="=" character.error) || (c !="upperCaseChar))" break scan; firstlower +="srcCount;" return this; char[] result="new" char[len]; * may grow resultoffset="0;" grow, so i+resultoffset is the write location in just copy first few uppercase characters. system.arraycopy(value, 0, result, firstlower); string lang="locale.getLanguage();" boolean localedependent="(lang" =="tr" 'az' 'lt'); upperchararray; upperchar; srcchar; srccount; for (int i="firstLower;" <len; srcchar="(int)value[i];" ((char)srcchar>= Character.MIN_HIGH_SURROGATE &amp;&amp; (char)srcChar = Character.MIN_SUPPLEMENTARY_CODE_POINT)) { if (upperChar == Character.ERROR) { if (localeDependent) { upperCharArray = ConditionalSpecialCasing.toUpperCaseCharArray(this, i, locale); } else { upperCharArray = Character.toUpperCaseCharArray(srcChar); } } else if (srcCount == 2) { resultOffset += Character.toChars(upperChar, result, i + resultOffset) - srcCount; continue; } else { upperCharArray = Character.toChars(upperChar); } /* Grow result if needed */ int mapLen = upperCharArray.length; if (mapLen &gt; srcCount) { char[] result2 = new char[result.length + mapLen - srcCount]; System.arraycopy(result, 0, result2, 0, i + resultOffset); result = result2; } for (int x = 0; x <maplen; ++x) { result[i + resultoffset x]="upperCharArray[x];" } - srccount); else resultoffset]="(char)upperChar;" return new string(result, 0, len resultoffset); < pre> <hr> <h3>Signature</h3> <p>There are two variant of toUpperCase() method. The signature or syntax of string toUpperCase() method is given below:</p> <pre> public String toUpperCase() public String toUpperCase(Locale locale) </pre> <p>The second method variant of toUpperCase(), converts all the characters into uppercase using the rules of given Locale.</p> <hr> <h3>Returns</h3> <p>string in uppercase letter.</p> <hr> <h2>Java String toUpperCase() method example</h2> <pre> public class StringUpperExample{ public static void main(String args[]){ String s1=&apos;hello string&apos;; String s1upper=s1.toUpperCase(); System.out.println(s1upper); }} </pre> <span> Test it Now </span> <p>Output:</p> <pre> HELLO STRING </pre> <h2>Java String toUpperCase(Locale locale) Method Example 2</h2> <pre> import java.util.Locale; public class StringUpperExample2 { public static void main(String[] args) { String s = &apos;hello string&apos;; String turkish = s.toUpperCase(Locale.forLanguageTag(&apos;tr&apos;)); String english = s.toUpperCase(Locale.forLanguageTag(&apos;en&apos;)); System.out.println(turkish);//will print I with dot on upper side System.out.println(english); } }</pre> <p>Output:</p> <pre> HELLO STR?NG HELLO STRING </pre></maplen;></=>

toUpperCase()의 두 번째 메소드 변형은 주어진 Locale의 규칙을 사용하여 모든 문자를 대문자로 변환합니다.

보고

대문자로 된 문자열입니다.

Java String toUpperCase() 메소드 예

 public class StringUpperExample{ public static void main(String args[]){ String s1='hello string'; String s1upper=s1.toUpperCase(); System.out.println(s1upper); }} 

산출:

 HELLO STRING 

Java 문자열 toUpperCase(Locale locale) 방법 예 2

 import java.util.Locale; public class StringUpperExample2 { public static void main(String[] args) { String s = 'hello string'; String turkish = s.toUpperCase(Locale.forLanguageTag('tr')); String english = s.toUpperCase(Locale.forLanguageTag('en')); System.out.println(turkish);//will print I with dot on upper side System.out.println(english); } }

산출:

 HELLO STR?NG HELLO STRING