Java使用正则表达式获取子文本的方法示例

package cn.mingyuan.regexp.singlecharacter;
import java.util.regex.Matcher;
import java.util.regex.Pattern;
public class GroupIndexAndStartEndIndexTest {
/**
* @param args
*/
public static void main(String[] args) {
  // TODO Auto-generated method stub
  String str = "Hello,World! in Java.";
  Pattern pattern = Pattern.compile("W(or)(ld!)");
  Matcher matcher = pattern.matcher(str);
  while(matcher.find()){
  System.out.println("Group 0:"+matcher.group(0));//得到第0组——整个匹配
  System.out.println("Group 1:"+matcher.group(1));//得到第一组匹配——与(or)匹配的
  System.out.println("Group 2:"+matcher.group(2));//得到第二组匹配——与(ld!)匹配的，组也就是子表达式
  System.out.println("Start 0:"+matcher.start(0)+" End 0:"+matcher.end(0));//总匹配的索引
  System.out.println("Start 1:"+matcher.start(1)+" End 1:"+matcher.end(1));//第一组匹配的索引
  System.out.println("Start 2:"+matcher.start(2)+" End 2:"+matcher.end(2));//第二组匹配的索引
  System.out.println(str.substring(matcher.start(0),matcher.end(1)));//从总匹配开始索引到第1组匹配的结束索引之间子串——Wor
  }
}
}

Group 0:World!
Group 1:or
Group 2:ld!
Start 0:6 End 0:12
Start 1:7 End 1:9
Start 2:9 End 2:12
Wor