JAVA正则表达式

package myPro;

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

public class myPro {
    public static void main(String args[]) {
        /*
        Pattern pattern = Pattern.compile("John");
        Matcher matcher = pattern.matcher("John does this, and John does that");

        String s2 = matcher.replaceAll("sam");
        System.out.println("replaceAll = "+s2);

        System.out.println("-----------------------------------------------");
        StringBuffer s3 = new StringBuffer();
        while(matcher.find()) {//每找到一次就输出一次
            matcher.appendReplacement(s3, "sam");
            System.out.println(s3.toString());
        }
        System.out.println("---------------------------------------------");

        String s2 = matcher.replaceFirst("sam");
        System.out.println("replaceFirst = "+s2);
        System.out.println("-------------------------------------");
        */
        Pattern pattern = Pattern.compile("a");
        Matcher matcher = pattern.matcher("This is a text");
        while(matcher.find()) {
            System.out.println("Match started at:"+matcher.start(0));
            System.out.println("Match ended at :"+matcher.end(0));//输出最后一个元素的后一个位置
        }


    }
}