Java正则边界匹配器[\A]匹配

边界匹配器[\A]匹配输入的开头。

示例

以下示例显示了边界匹配器的用法。

package com.zaixian;

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

public class BoundaryMatcherDemo {
   private static final String REGEX = "\\A";
   private static final String INPUT = "Welcome to xuhuhu.com";

   public static void main(String[] args) {
      // create a pattern
      Pattern  pattern = Pattern.compile(REGEX);

      // get a matcher object
      Matcher matcher = pattern.matcher(INPUT); 

      while(matcher.find()) {
         //Prints the start index of the match.
         System.out.println("Match String start(): "+matcher.start());
      }
   }
}

编译并运行上面的程序，这将产生以下结果 -

Match String start(): 0