[Java] 문자열 공백 제거 trim, replace, strip

1. trim()

• 문자열 앞 뒤 공백 제거

String str = " first and end character are blank ";
System.out.println("[" + str + "]");
System.out.println("[" + str.trim() + "]");

• 출력
  [ first and end character are blank ][first and end character are blank]

2. replace(), replaceAll()

• replace(a, b), replaceAll(a, b) : a를 b로 교체
• 모든 공백 제거

String str = " first and end character are blank ";
System.out.println("[" + str + "]");
System.out.println("[" + str.replaceAll(" ", "") + "]");

• 출력
  [ first and end character are blank ][firstandendcharacterareblank]
  

3. strip()

• 문자열 앞 뒤 공백 제거

String str = " first and end character are blank ";
System.out.println("[" + str + "]");
System.out.println("[" + str.trim() + "]");

• 출력
  [ first and end character are blank ][first and end character are blank]
  
• stripLeading(), stripTrailing() : 각각 문자열의 앞, 뒤 공백을 제거

trim, strip 차이

• trim : '\u0020' 이하 공백 제거
• strip : 유니코드 상의 공백 제거
  (ex. 스페이스('\u0020'), 탭('\u0009))
  

// \u2003 == EM SPACE
String str = "\u2003first and end character are blank\u2003";
System.out.println("[" + str.trim() + "]");
System.out.println("[" + str.strip() + "]");

• 출력
  [ first and end character are blank ][first and end character are blank]