Java 正则表达式 - 边界匹配器 [\A] 匹配

描述

边界匹配器 [\A] 匹配输入的开头。

示例

以下示例展示了边界匹配器的用法。

package com.tutorialspoint;

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 TutorialsPoint.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());
      }
   }
}

让我们编译并运行以上程序，将产生以下结果 −

Match String start(): 0