Java正則Possessive量詞[X?+]匹配

Possesive量詞[x?+]匹配存在一次或根本不存在的X.

範例
以下範例顯示了所有Possesive量詞的用法。

package com.yiibai;

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

public class PossesiveQuantifierDemo {
   private static final String REGEX = "T?+";
   private static final String INPUT = "abcdTatW";

   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());
      }
   }
}

編譯並執行上面的程式，這將產生以下結果 -

Match String start(): 0
Match String start(): 1
Match String start(): 2
Match String start(): 3
Match String start(): 4
Match String start(): 5
Match String start(): 6
Match String start(): 7
Match String start(): 8