1. 量词的小细节,贪婪与懒惰
2. find()/find(i)方法
3. (?m) 单行模式 :标记的作用及用法(了解,用到时扩展)
import java.util.regex.Matcher; import java.util.regex.Pattern; public class TestRegex { public static void main(String[] args) { String str = "abcabcabc"; System.out.println(str.replaceFirst("(abc)+","---")); //abc出现一次或多次 System.out.println(str.replaceFirst("abc+","---")); //ab后面的C出现一次或多次 System.out.println(str.replaceFirst("\\S+?","---")); //贪婪模式,尽力匹配 System.out.println(str.replaceFirst("\\S+","---")); //懒惰模式,最少匹配 StringBuilder sb = new StringBuilder(); Matcher m = Pattern.compile("\\w+").matcher("Evening is full of the linnet's wings"); while(m.find()) { sb.append(m.group()).append(" "); } System.out.println(sb.toString()); sb.setLength(0); int i = 0; while(m.find(i)) { //设置find的起点 sb.append(m.group()).append(" "); i++; } System.out.println(sb.toString()); sb.setLength(0); String str2 = "i have a big ice\n" + "you not have ice\n"; //(?m)启动单行模式,此时^$符号表示每行的开头结尾,而不是整个字符串的开头结尾 Matcher m2 = Pattern.compile("(?m)(\\S+)\\s+((\\S+)\\s+(\\S+))$").matcher(str2); while(m2.find()) { for(int j=0; j<=m2.groupCount(); j++) { sb.append("[").append(m2.group(j)).append("]"); } System.out.println(sb.toString()); sb.setLength(0); } //find matches lookingAt区别 } }
//output --- ---abcabc ---bcabcabc --- Evening is full of the linnet s wings Evening vening ening ning ing ng g is is s full full ull ll l of of f the the he e linnet linnet innet nnet net et t s s wings wings ings ngs gs s [a big ice][a][big ice][big][ice] [not have ice][not][have ice][have][ice]
4. appendReplacement()、appendTail()
5.reset()
import java.util.regex.Matcher; import java.util.regex.Pattern; public class TestRegex2 { public static void main(String[] args) { Pattern p = Pattern.compile("cat"); Matcher m = p.matcher("one cat two cats in cat the cat yard cat"); StringBuffer sb = new StringBuffer(); int i = 0; while (m.find()) { if (i % 2 == 0) { m.appendReplacement(sb,"dog"); } i++; } m.appendTail(sb); System.out.println(sb.toString()); sb.setLength(0); // reset()重新matcher字符串 m.reset("one cat two cats in the yard"); while (m.find()) { m.appendReplacement(sb,"dog"); } m.appendTail(sb); System.out.println(sb.toString()); } }
//output one dog two cats in dog the cat yard dog one dog two dogs in the yard