（3）正则补充

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());}}

//outputone dog two cats in dog the cat yard dogone dog two dogs in the yard