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id, title, category, status, verification_status, canonical_id, aliases, duplicate_of, source_trust_level, confidence_score, created_at, updated_at, review_reason, merge_history, tags, raw_sources, applied_in, github_commit
id title category status verification_status canonical_id aliases duplicate_of source_trust_level confidence_score created_at updated_at review_reason merge_history tags raw_sources applied_in github_commit
java-regex Java RegEx Programming_Language draft conceptual
regular expressions
자바 정규표현식
B 0.88 2026-07-04 2026-07-04
java
programming
w3schools
regex
https://www.w3schools.com/java/java_regex.asp

Java RegEx

🎯 한 줄 통찰 (One-line insight)

Java has no built-in Regular Expression type — like dates, regex requires importing java.util.regex (Pattern + Matcher classes), and the search flow is explicitly two-step: Pattern.compile() builds the pattern object first, then .matcher(text).find() runs the actual search against a specific string, decoupling "what to search for" from "where to search." [S1]

🧠 핵심 개념 (Core concepts)

  • Regular expression — a sequence of characters forming a search pattern for text search/replace. [S1]
  • java.util.regex package — required import; contains Pattern, Matcher, PatternSyntaxException. [S1]
  • Pattern.compile(regex, flags) — builds the pattern; flags are optional (e.g. Pattern.CASE_INSENSITIVE). [S1]
  • pattern.matcher(text) — returns a Matcher bound to a specific string. [S1]
  • matcher.find() — returns true/false depending on whether the pattern matches. [S1]
  • Bracket expressions[abc] (any of a/b/c), [^abc] (none of a/b/c), [0-9] (digit range). [S1]
  • Metacharacters| (alternation), . (any char), ^/$ (start/end anchors), \d (digit), \s (whitespace), \b (word boundary), \uxxxx (Unicode). [S1]
  • Quantifiersn+, n*, n?, n{x}, n{x,y}, n{x,}. [S1]

📖 세부 내용 (Details)

  • Basic case-insensitive search: Pattern pattern = Pattern.compile("w3schools", Pattern.CASE_INSENSITIVE); Matcher matcher = pattern.matcher("Visit W3Schools!"); boolean matchFound = matcher.find(); // true. [S1]
  • Flags: Pattern.CASE_INSENSITIVE, Pattern.LITERAL (treats special chars as ordinary), Pattern.UNICODE_CASE (extends case-insensitivity beyond English). [S1]

⚖️ 모순 및 업데이트 (Contradictions & updates)

소스에서 모순되는 정보는 발견되지 않음.

🛠️ 적용 사례 (Applied in summary)

현재 발견된 실제 적용 사례가 없습니다 — 대소문자 구분 없이 특정 단어의 존재 여부를 검사하는 것이 정규표현식의 가장 기본적인 실전 활용이다. [S1]

💻 코드 패턴 (Code patterns)

Case-insensitive pattern search (Java):

import java.util.regex.Matcher;
import java.util.regex.Pattern;

Pattern pattern = Pattern.compile("w3schools", Pattern.CASE_INSENSITIVE);
Matcher matcher = pattern.matcher("Visit W3Schools!");
boolean matchFound = matcher.find(); // true

검증 상태 및 신뢰도

  • 상태: draft
  • 검증 단계: conceptual
  • 출처 신뢰도: B (W3Schools — widely used educational reference, not a primary standards body)
  • 신뢰 점수: 0.88
  • 중복 검사 결과: 신규 생성 (New discovery)

🔗 지식 그래프 (Knowledge Graph)

📚 출처 (Sources)

📝 변경 이력 (Change history)

  • 2026-07-04: Initial draft synthesized from the W3Schools "Java Regular Expressions" page (Astra wiki-curation, P-Reinforce v3.1 format).