正则表达式学习笔记

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

public class Test {

	public static void main(String[] args) {
		// 简单认识正则表达式的概念
		// p("abc".matches("..."));
		// p("a8729asj34fdfhdh".replaceAll("\\d", "-"));
		// p("a8729asj34fdfhdh".replaceAll("\\D", "-"));
		//
		// Pattern p=Pattern.compile("[a-z]{3}");//编译好，速度快 Matcher
		// m=p.matcher("fgh");//匹配后的结果 p(m.matches());
		//
		// p("fgh".matches("[a-z]{3}"));

		// 初步认识 . * + ?
		// p("a".matches("."));
		// p("aa".matches("aa"));
		// p("aaaa".matches("a*"));
		// p("aaaa".matches("a?"));
		// p("a".matches("a?"));
		// p("".matches("a?"));
		// p("aaaa".matches("a{4}"));
		// p("aaaa".matches("a{2,}"));
		// p("aaaa".matches("a{2,3}"));
		// p("aaaa".matches("a{2,6}"));
		// p("34567893456734567894356".matches("\\d{2,100}"));
		// p("127.0.0.1".matches("\\d{1,3}\\.\\d{1,3}\\.\\d{1,3}\\.\\d{1,3}"));
		// p("392".matches("[0-2][0-9][0-9]"));

		// 范围

		// p("a".matches("[abc]"));
		// p("a".matches("[^abc]"));
		// p("p".matches("[^abc]"));
		// p("A".matches("[a-zA-Z]"));
		// p("A".matches("[a-z]|[A-Z]"));
		// p("A".matches("[a-z[A-Z]]"));
		// p("R".matches("[A-Z&&[RFG]]"));

		// 认识 \s \w \d \
		// p(" \n\r\t".matches("\\s{4}"));
		// p(" ".matches("\\S"));
		// p("s".matches("\\S"));
		// p("fhdsgufs346873".matches("\\w{2,}"));
		// p("&_73".matches("\\w{2,}"));
		// p("abc888$%#".matches("[a-z]{1,3}\\d+[#$%^&*]+"));
		// p("\\".matches("\\\\"));

		// 边界处理

		// POSIX Style

		// p("a".matches("\\p{Lower}"));

		// boundary

		// p("hello sir".matches("^h.*"));
		// p("hello sir".matches(".*ir$"));
		// p("hello sir".matches("^he.*ir$"));
		// p("hello sir".matches("^h[a-z]{1,3}o\\b.*"));
		// p("hellosir".matches("^h[a-z]{1,3}o\\b.*"));

		// white lines

		// p(" \n".matches("^[\\s&&[^\\n]]*\\n$"));
		// p("aaa 8888c".matches(".*\\d{4}."));
		// p("aaa 8888c".matches(".*\\b\\d{4}."));
		// p("aaa8888c".matches(".*\\d{4}."));
		// p("aaa8888c".matches(".*\\b\\d{4}."));

		// Email

		// p("Jack_Wong-2010@163.com".matches("[\\w[.-]]+@[\\w[.-]]+.[\\w]"));

		// match find lookingAt

		/*
		 * Pattern p = Pattern.compile("\\d{3,5}"); String s =
		 * "12434-5454-656-00"; Matcher m = p.matcher(s); // p(m.matches());
		 * m.reset(); p(m.find());// 找子川去掉匹配子串 p(m.start()+" - "+m.end());
		 * p(m.find());// 找子川 p(m.start()+" - "+m.end()); p(m.find());// 找子川
		 * p(m.start()+" - "+m.end()); p(m.find());// 找子川
		 * //p(m.start()+" - "+m.end());
		 * 
		 * p(m.lookingAt()); p(m.lookingAt()); p(m.lookingAt());
		 * p(m.lookingAt());
		 */

		// replacement

		/*
		 * Pattern p = Pattern.compile("java", Pattern.CASE_INSENSITIVE);
		 * Matcher m =
		 * p.matcher("java Java JaVa JAVa ILOVEJAVA you HATEjAVA fddsdgfbkjs");
		 * // p(m.replaceAll("JAVA")); StringBuffer buf = new StringBuffer();
		 * int i = 0; while (m.find()) { i++; if (i % 2 == 0) {
		 * m.appendReplacement(buf, "java"); } else { m.appendReplacement(buf,
		 * "JAVA"); } } m.appendTail(buf); p(buf);
		 */

		/*Pattern p = Pattern.compile("(\\d{3,5})([a-z]{2})");
		String s = "123aa-34345bb-234-004cc";
		Matcher m = p.matcher(s);
		while(m.find()){
			p(m.group(2));
		}
		*/
		
		//qulifiers
		
		/*Pattern p=Pattern.compile("(.{3,10}+)[0-9]");
		String s="aaaa5bbbb6";
		Matcher m=p.matcher(s);
		if(m.find()){
			p(m.start()+"-"+m.end());
		}else{
			p("not Match!");
		}*/
		
		//non-capturing groups
		
		/*Pattern p=Pattern.compile(".{3}(?=a)");
		String s="443a66b";
		Matcher m=p.matcher(s);
		if(m.find()){
			p(m.group());
		}*/
		
		//back reference
		
		/*Pattern p=Pattern.compile("(\\d(\\d))\\2");
		String s="1212";
		Matcher m=p.matcher(s);
		if(m.find()){
			p(m.group());
		}*/
		
		//flags的简写
		
		p("Java".matches("(?i)(java)"));
		
	}

	public static void p(Object o) {
		System.out.println(o);
	}
}