[Java] 正则表达式 01 (基本都概览)

利器RegularExpressions

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("a8729a".replaceAll("\\d", "-")); Pattern
         * p = Pattern.compile("[a-z]{3}"); Matcher m = p.matcher("fgh"); //
         * 有限状态自动机 p(m.matches()); p("fgha".matches("[a-z]{3}"));
         */

        // 初步认识. * + ?
        /*
         * p("a".matches(".")); p("aa".matches("aa")); p("aaaa".matches("a*"));
         * p("aaaa".matches("a+")); p("".matches("a*"));
         * p("aaaa".matches("a?")); p("".matches("a?")); p("a".matches("a?"));
         * p("214523145234532".matches("\\d{3,100}"));
         * p("192.168.0.aaa".matches(
         * "\\d{1,3}\\.\\d{1,3}\\.\\d{1,3}\\.\\d{1,3}"));
         * p("192".matches("[0-2][0-9][0-9]"));
         */

        // 范围
        /*
         * p("a".matches("[abc]")); p("a".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("a_8".matches("\\w{3}"));
         * p("abc888&^%".matches("[a-z]{1,3}\\d+[&^#%]+"));
         * p("\\".matches("\\\\"));
         */

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

        // boundary
        /*
         * p("hello sir".matches("^h.*")); p("hello sir".matches(".*ir$"));
         * p("hello sir".matches("^h[a-z]{1,3}o\\b.*"));
         * p("hellosir".matches("^h[a-z]{1,3}o\\b.*")); //whilte lines
         * p(" \n".matches("^[\\s&&[^\\n]]*\\n$")); // 开头是空白字符但不是换行符
         * 
         * 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("asdfasdfsafsf@dsdfsdf.com".matches("[\\w[.-]]+@[\\w[.-]]+\\.[\\w]+"));

        // matches find lookingAt
        /*
         * Pattern p = Pattern.compile("\\d{3,5}"); String s =
         * "123-34345-234-00"; Matcher m = p.matcher(s); p(m.matches());
         * m.reset(); p(m.find()); p(m.start() + "-" + m.end()); p(m.find());
         * p(m.start() + "-" + m.end()); p(m.find()); p(m.start() + "-" +
         * m.end()); p(m.find()); //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 afasdfasdf");
         * 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);
         */

        // group
        /*
         * Pattern p = Pattern.compile("(\\d{3,5})([a-z]{2})"); String s =
         * "123aa-34345bb-234cc-00"; Matcher m = p.matcher(s); while(m.find()) {
         * p(m.group()); }
         */

        // qulifiers
        /*
         * Pattern p = Pattern.compile(".{3,10}+[0-9]"); String s =
         * "aaaa5bbbb68"; 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 = "444a66b";
         * Matcher m = p.matcher(s); while(m.find()) { p(m.group()); }
         */

        // back refenrences
        /*
         * Pattern p = Pattern.compile("(\\d(\\d))\\2"); String s = "122";
         * Matcher m = p.matcher(s); p(m.matches());
         */

        // flags的简写
        // Pattern p = Pattern.compile("java", Pattern.CASE_INSENSITIVE);
        p("Java".matches("(?i)(java)"));
    }

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